man > migration_guide(7ssl)

MIGRATION_GUIDE(7SSL)                          OpenSSL                         MIGRATION_GUIDE(7SSL)

NAME
       migration_guide - OpenSSL migration guide

SYNOPSIS
       See the individual manual pages for details.

DESCRIPTION
       This guide details the changes required to migrate to new versions of OpenSSL.  Currently
       this covers OpenSSL 3.0. For earlier versions refer to
       <https://github.com/openssl/openssl/blob/master/CHANGES.md>.  For an overview of some of the
       key concepts introduced in OpenSSL 3.0 see crypto(7).

OPENSSL 3.0
   Main Changes from OpenSSL 1.1.1
       Major Release

       OpenSSL 3.0 is a major release and consequently any application that currently uses an older
       version of OpenSSL will at the very least need to be recompiled in order to work with the new
       version. It is the intention that the large majority of applications will work unchanged with
       OpenSSL 3.0 if those applications previously worked with OpenSSL 1.1.1. However this is not
       guaranteed and some changes may be required in some cases. Changes may also be required if
       applications need to take advantage of some of the new features available in OpenSSL 3.0 such
       as the availability of the FIPS module.

       License Change

       In previous versions, OpenSSL was licensed under the dual OpenSSL and SSLeay licenses
       <https://www.openssl.org/source/license-openssl-ssleay.txt> (both licenses apply). From
       OpenSSL 3.0 this is replaced by the Apache License v2 <https://www.openssl.org/source/apache-
       license-2.0.txt>.

       Providers and FIPS support

       One of the key changes from OpenSSL 1.1.1 is the introduction of the Provider concept.
       Providers collect together and make available algorithm implementations.  With OpenSSL 3.0 it
       is possible to specify, either programmatically or via a config file, which providers you
       want to use for any given application.  OpenSSL 3.0 comes with 5 different providers as
       standard. Over time third parties may distribute additional providers that can be plugged
       into OpenSSL.  All algorithm implementations available via providers are accessed through the
       "high level" APIs (for example those functions prefixed with "EVP"). They cannot be accessed
       using the "Low Level APIs".

       One of the standard providers available is the FIPS provider. This makes available FIPS
       validated cryptographic algorithms.  The FIPS provider is disabled by default and needs to be
       enabled explicitly at configuration time using the "enable-fips" option. If it is enabled,
       the FIPS provider gets built and installed in addition to the other standard providers. No
       separate installation procedure is necessary.  There is however a dedicated "install_fips"
       make target, which serves the special purpose of installing only the FIPS provider into an
       existing OpenSSL installation.

       Not all algorithms may be available for the application at a particular moment.  If the
       application code uses any digest or cipher algorithm via the EVP interface, the application
       should verify the result of the EVP_EncryptInit(3), EVP_EncryptInit_ex(3), and
       EVP_DigestInit(3) functions. In case when the requested algorithm is not available, these
       functions will fail.

       See also "Legacy Algorithms" for information on the legacy provider.

       See also "Completing the installation of the FIPS Module" and "Using the FIPS Module in
       applications".

       Low Level APIs

       OpenSSL has historically provided two sets of APIs for invoking cryptographic algorithms: the
       "high level" APIs (such as the "EVP" APIs) and the "low level" APIs. The high level APIs are
       typically designed to work across all algorithm types. The "low level" APIs are targeted at a
       specific algorithm implementation.  For example, the EVP APIs provide the functions
       EVP_EncryptInit_ex(3), EVP_EncryptUpdate(3) and EVP_EncryptFinal(3) to perform symmetric
       encryption. Those functions can be used with the algorithms AES, CHACHA, 3DES etc.  On the
       other hand, to do AES encryption using the low level APIs you would have to call AES specific
       functions such as AES_set_encrypt_key(3), AES_encrypt(3), and so on. The functions for 3DES
       are different.  Use of the low level APIs has been informally discouraged by the OpenSSL
       development team for a long time. However in OpenSSL 3.0 this is made more formal. All such
       low level APIs have been deprecated. You may still use them in your applications, but you may
       start to see deprecation warnings during compilation (dependent on compiler support for
       this). Deprecated APIs may be removed from future versions of OpenSSL so you are strongly
       encouraged to update your code to use the high level APIs instead.

       This is described in more detail in "Deprecation of Low Level Functions"

       Legacy Algorithms

       Some cryptographic algorithms such as MD2 and DES that were available via the EVP APIs are
       now considered legacy and their use is strongly discouraged.  These legacy EVP algorithms are
       still available in OpenSSL 3.0 but not by default. If you want to use them then you must load
       the legacy provider.  This can be as simple as a config file change, or can be done
       programmatically.  See OSSL_PROVIDER-legacy(7) for a complete list of algorithms.
       Applications using the EVP APIs to access these algorithms should instead use more modern
       algorithms. If that is not possible then these applications should ensure that the legacy
       provider has been loaded. This can be achieved either programmatically or via configuration.
       See crypto(7) man page for more information about providers.

       Engines and "METHOD" APIs

       The refactoring to support Providers conflicts internally with the APIs used to support
       engines, including the ENGINE API and any function that creates or modifies custom "METHODS"
       (for example EVP_MD_meth_new(3), EVP_CIPHER_meth_new(3), EVP_PKEY_meth_new(3),
       RSA_meth_new(3), EC_KEY_METHOD_new(3), etc.). These functions are being deprecated in OpenSSL
       3.0, and users of these APIs should know that their use can likely bypass provider selection
       and configuration, with unintended consequences.  This is particularly relevant for
       applications written to use the OpenSSL 3.0 FIPS module, as detailed below. Authors and
       maintainers of external engines are strongly encouraged to refactor their code transforming
       engines into providers using the new Provider API and avoiding deprecated methods.

       Support of legacy engines

       If openssl is not built without engine support or deprecated API support, engines will still
       work. However, their applicability will be limited.

       New algorithms provided via engines will still work.

       Engine-backed keys can be loaded via custom OSSL_STORE implementation.  In this case the
       EVP_PKEY objects created via ENGINE_load_private_key(3) will be considered legacy and will
       continue to work.

       To ensure the future compatibility, the engines should be turned to providers.  To prefer the
       provider-based hardware offload, you can specify the default properties to prefer your
       provider.

       Versioning Scheme

       The OpenSSL versioning scheme has changed with the OpenSSL 3.0 release. The new versioning
       scheme has this format:

       MAJOR.MINOR.PATCH

       For OpenSSL 1.1.1 and below, different patch levels were indicated by a letter at the end of
       the release version number. This will no longer be used and instead the patch level is
       indicated by the final number in the version. A change in the second (MINOR) number indicates
       that new features may have been added. OpenSSL versions with the same major number are API
       and ABI compatible.  If the major number changes then API and ABI compatibility is not
       guaranteed.

       For more information, see OpenSSL_version(3).

       Other major new features

       Certificate Management Protocol (CMP, RFC 4210)

       This also covers CRMF (RFC 4211) and HTTP transfer (RFC 6712) See openssl-cmp(1) and
       OSSL_CMP_exec_certreq(3) as starting points.

       HTTP(S) client

       A proper HTTP(S) client that supports GET and POST, redirection, plain and ASN.1-encoded
       contents, proxies, and timeouts.

       Key Derivation Function API (EVP_KDF)

       This simplifies the process of adding new KDF and PRF implementations.

       Previously KDF algorithms had been shoe-horned into using the EVP_PKEY object which was not a
       logical mapping.  Existing applications that use KDF algorithms using EVP_PKEY (scrypt, TLS1
       PRF and HKDF) may be slower as they use an EVP_KDF bridge internally.  All new applications
       should use the new EVP_KDF(3) interface.  See also "Key Derivation Function (KDF)" in
       OSSL_PROVIDER-default(7) and "Key Derivation Function (KDF)" in OSSL_PROVIDER-FIPS(7).

       Message Authentication Code API (EVP_MAC)

       This simplifies the process of adding MAC implementations.

       This includes a generic EVP_PKEY to EVP_MAC bridge, to facilitate the continued use of MACs
       through raw private keys in functionality such as EVP_DigestSign(3) and EVP_DigestVerify(3).

       All new applications should use the new EVP_MAC(3) interface.  See also "Message
       Authentication Code (MAC)" in OSSL_PROVIDER-default(7) and "Message Authentication Code
       (MAC)" in OSSL_PROVIDER-FIPS(7).

       Algorithm Fetching

       Using calls to convenience functions such as EVP_sha256() and EVP_aes_256_gcm() may incur a
       performance penalty when using providers.  Retrieving algorithms from providers involves
       searching for an algorithm by name.  This is much slower than directly accessing a method
       table.  It is recommended to prefetch algorithms if an algorithm is used many times.  See
       "Performance" in crypto(7), "Explicit fetching" in crypto(7) and "Implicit fetching" in
       crypto(7).

       Support for Linux Kernel TLS

       In order to use KTLS, support for it must be compiled in using the "enable-ktls"
       configuration option. It must also be enabled at run time using the SSL_OP_ENABLE_KTLS
       option.

       New Algorithms

       •   KDF algorithms "SINGLE STEP" and "SSH"

           See EVP_KDF-SS(7) and EVP_KDF-SSHKDF(7)

       •   MAC Algorithms "GMAC" and "KMAC"

           See EVP_MAC-GMAC(7) and EVP_MAC-KMAC(7).

       •   KEM Algorithm "RSASVE"

           See EVP_KEM-RSA(7).

       •   Cipher Algorithm "AES-SIV"

           See "SIV Mode" in EVP_EncryptInit(3).

       •   AES Key Wrap inverse ciphers supported by EVP layer.

           The  inverse  ciphers use AES decryption for wrapping, and AES encryption for unwrapping.
           The   algorithms   are:   "AES-128-WRAP-INV",   "AES-192-WRAP-INV",   "AES-256-WRAP-INV",
           "AES-128-WRAP-PAD-INV", "AES-192-WRAP-PAD-INV" and "AES-256-WRAP-PAD-INV".

       •   CTS ciphers added to EVP layer.

           The    algorithms    are    "AES-128-CBC-CTS",    "AES-192-CBC-CTS",   "AES-256-CBC-CTS",
           "CAMELLIA-128-CBC-CTS", "CAMELLIA-192-CBC-CTS" and "CAMELLIA-256-CBC-CTS".  CS1, CS2  and
           CS3 variants are supported.

       CMS and PKCS#7 updates

       •   Added CAdES-BES signature verification support.

       •   Added CAdES-BES signature scheme and attributes support (RFC 5126) to CMS API.

       •   Added AuthEnvelopedData content type structure (RFC 5083) using AES_GCM

           This  uses  the  AES-GCM  parameter (RFC 5084) for the Cryptographic Message Syntax.  Its
           purpose is to support encryption and decryption  of  a  digital  envelope  that  is  both
           authenticated and encrypted using AES GCM mode.

       •   PKCS7_get_octet_string(3) and PKCS7_type_is_other(3) were made public.

       PKCS#12 API updates

       The  default algorithms for pkcs12 creation with the PKCS12_create() function were changed to
       more modern PBKDF2 and AES based algorithms. The default MAC iteration count was  changed  to
       PKCS12_DEFAULT_ITER  to make it equal with the password-based encryption iteration count. The
       default digest algorithm  for  the  MAC  computation  was  changed  to  SHA-256.  The  pkcs12
       application  now  supports  -legacy  option  that restores the previous default algorithms to
       support interoperability with legacy systems.

       Added enhanced PKCS#12 APIs which accept a library context OSSL_LIB_CTX and (where  relevant)
       a  property  query. Other APIs which handle PKCS#7 and PKCS#8 objects have also been enhanced
       where required. This includes:

       PKCS12_add_key_ex(3),  PKCS12_add_safe_ex(3),  PKCS12_add_safes_ex(3),   PKCS12_create_ex(3),
       PKCS12_decrypt_skey_ex(3),          PKCS12_init_ex(3),         PKCS12_item_decrypt_d2i_ex(3),
       PKCS12_item_i2d_encrypt_ex(3),      PKCS12_key_gen_asc_ex(3),       PKCS12_key_gen_uni_ex(3),
       PKCS12_key_gen_utf8_ex(3),        PKCS12_pack_p7encdata_ex(3),        PKCS12_pbe_crypt_ex(3),
       PKCS12_PBE_keyivgen_ex(3),                         PKCS12_SAFEBAG_create_pkcs8_encrypt_ex(3),
       PKCS5_pbe2_set_iv_ex(3),           PKCS5_pbe_set0_algor_ex(3),           PKCS5_pbe_set_ex(3),
       PKCS5_pbkdf2_set_ex(3),     PKCS5_v2_PBE_keyivgen_ex(3),      PKCS5_v2_scrypt_keyivgen_ex(3),
       PKCS8_decrypt_ex(3), PKCS8_encrypt_ex(3), PKCS8_set0_pbe_ex(3).

       As  part  of  this change the EVP_PBE_xxx APIs can also accept a library context and property
       query and will call an extended version of the  key/IV  derivation  function  which  supports
       these    parameters.   This   includes   EVP_PBE_CipherInit_ex(3),   EVP_PBE_find_ex(3)   and
       EVP_PBE_scrypt_ex(3).

       PKCS#12 KDF versus FIPS

       Unlike in 1.x.y, the PKCS12KDF algorithm used when a PKCS#12 structure is created with a  MAC
       that  does  not  work  with  the  FIPS  provider  as  the  PKCS12KDF is not a FIPS approvable
       mechanism.

       See EVP_KDF-PKCS12KDF(7), PKCS12_create(3), openssl-pkcs12(1), OSSL_PROVIDER-FIPS(7).

       Windows thread synchronization changes

       Windows thread synchronization uses read/write primitives (SRWLock) when supported by the OS,
       otherwise CriticalSection continues to be used.

       Trace API

       A new generic trace API has been added which provides support  for  enabling  instrumentation
       through  trace  output.  This  feature  is  mainly  intended  as an aid for developers and is
       disabled by default. To utilize it, OpenSSL needs to be configured  with  the  "enable-trace"
       option.

       If  the tracing API is enabled, the application can activate trace output by registering BIOs
       as   trace   channels   for   a   number   of   tracing   and   debugging   categories.   See
       OSSL_trace_enabled(3).

       Key validation updates

       EVP_PKEY_public_check(3)  and  EVP_PKEY_param_check(3)  now  work  for  more  key types. This
       includes RSA, DSA, ED25519, X25519, ED448 and X448.  Previously (in 1.1.1) they would  return
       -2. For key types that do not have parameters then EVP_PKEY_param_check(3) will always return
       1.

       Other notable deprecations and changes

       The function code part of an OpenSSL error code is no longer relevant

       This code is now always set to zero. Related functions are deprecated.

       STACK and HASH macros have been cleaned up

       The  type-safe wrappers are declared everywhere and implemented once.  See DEFINE_STACK_OF(3)
       and DECLARE_LHASH_OF(3).

       The RAND_DRBG subsystem has been removed

       The new EVP_RAND(3) is a partial replacement: the DRBG  callback  framework  is  absent.  The
       RAND_DRBG  API  did not fit well into the new provider concept as implemented by EVP_RAND and
       EVP_RAND_CTX.

       Removed FIPS_mode() and FIPS_mode_set()

       These functions are  legacy  APIs  that  are  not  applicable  to  the  new  provider  model.
       Applications     should    instead    use    EVP_default_properties_is_fips_enabled(3)    and
       EVP_default_properties_enable_fips(3).

       Key generation is slower

       The Miller-Rabin test now uses 64 rounds, which is used for all prime  generation,  including
       RSA key generation. This affects the time for larger keys sizes.

       The  default  key  generation  method  for  the  regular  2-prime RSA keys was changed to the
       FIPS186-4 B.3.6 method (Generation of Probable Primes  with  Conditions  Based  on  Auxiliary
       Probable Primes). This method is slower than the original method.

       Change PBKDF2 to conform to SP800-132 instead of the older PKCS5 RFC2898

       This checks that the salt length is at least 128 bits, the derived key length is at least 112
       bits,  and  that  the  iteration  count  is at least 1000.  For backwards compatibility these
       checks are disabled by default in the default provider, but are enabled  by  default  in  the
       FIPS provider.

       To  enable or disable the checks see OSSL_KDF_PARAM_PKCS5 in EVP_KDF-PBKDF2(7). The parameter
       can be set using EVP_KDF_derive(3).

       Enforce a minimum DH modulus size of 512 bits

       Smaller sizes now result in an error.

       SM2 key changes

       EC EVP_PKEYs with the SM2 curve have  been  reworked  to  automatically  become  EVP_PKEY_SM2
       rather than EVP_PKEY_EC.

       Unlike   in   previous   OpenSSL   versions,   this   means  that  applications  cannot  call
       "EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2)" to get SM2 computations.

       Parameter and key generation is also reworked to make it possible  to  generate  EVP_PKEY_SM2
       parameters  and keys. Applications must now generate SM2 keys directly and must not create an
       EVP_PKEY_EC key first. It is no longer possible to import an SM2 key with  domain  parameters
       other than the SM2 elliptic curve ones.

       Validation of SM2 keys has been separated from the validation of regular EC keys, allowing to
       improve  the  SM2 validation process to reject loaded private keys that are not conforming to
       the SM2 ISO standard.  In particular, a private scalar k outside the range 1 <= k  <  n-1  is
       now correctly rejected.

       EVP_PKEY_set_alias_type() method has been removed

       This  function made a EVP_PKEY object mutable after it had been set up. In OpenSSL 3.0 it was
       decided that a provided key should not be able to change its type, so this function has  been
       removed.

       Functions that return an internal key should be treated as read only

       Functions such as EVP_PKEY_get0_RSA(3) behave slightly differently in OpenSSL 3.0. Previously
       they  returned  a pointer to the low-level key used internally by libcrypto. From OpenSSL 3.0
       this key may now be held in a provider. Calling these functions will only return a handle  on
       the  internal  key  where the EVP_PKEY was constructed using this key in the first place, for
       example using a function or macro such as EVP_PKEY_assign_RSA(3), EVP_PKEY_set1_RSA(3),  etc.
       Where  the  EVP_PKEY  holds  a provider managed key, then these functions now return a cached
       copy of the key. Changes to the internal provider key that take place after  the  first  time
       the  cached  key  is  accessed  will  not be reflected back in the cached copy. Similarly any
       changes made to the cached copy by application  code  will  not  be  reflected  back  in  the
       internal provider key.

       For  the  above reasons the keys returned from these functions should typically be treated as
       read-only.   To   emphasise   this   the   value    returned    from    EVP_PKEY_get0_RSA(3),
       EVP_PKEY_get0_DSA(3),  EVP_PKEY_get0_EC_KEY(3)  and EVP_PKEY_get0_DH(3) have been made const.
       This may break some existing code.  Applications broken by this change  should  be  modified.
       The  preferred  solution  is  to  refactor  the  code  to  avoid  the use of these deprecated
       functions. Failing this the code should be modified to use  a  const  pointer  instead.   The
       EVP_PKEY_get1_RSA(3),  EVP_PKEY_get1_DSA(3),  EVP_PKEY_get1_EC_KEY(3) and EVP_PKEY_get1_DH(3)
       functions continue to return a non-const pointer to enable them to be "freed".  However  they
       should also be treated as read-only.

       The public key check has moved from EVP_PKEY_derive() to EVP_PKEY_derive_set_peer()

       This  may  mean  result  in  an  error  in  EVP_PKEY_derive_set_peer(3)  rather  than  during
       EVP_PKEY_derive(3).  To disable this check use EVP_PKEY_derive_set_peer_ex(dh, peer, 0).

       The print format has cosmetic changes for some functions

       The  output   from   numerous   "printing"   functions   such   as   X509_signature_print(3),
       X509_print_ex(3),  X509_CRL_print_ex(3),  and  other  similar functions has been amended such
       that there may be cosmetic differences between the output observed in  1.1.1  and  3.0.  This
       also applies to the -text output from the openssl x509 and openssl crl applications.

       Interactive mode from the openssl program has been removed

       From now on, running it without arguments is equivalent to openssl help.

       The error return values from some control calls (ctrl) have changed

       One  significant  change  is  that  controls  which used to return -2 for invalid inputs, now
       return -1 indicating a generic error condition instead.

       DH and DHX key types have different settable parameters

       Previously (in 1.1.1) these conflicting parameters were  allowed,  but  will  now  result  in
       errors.   See   EVP_PKEY-DH(7)   for   further   details.   This  affects  the  behaviour  of
       openssl-genpkey(1) for DH parameter generation.

       EVP_CIPHER_CTX_set_flags() ordering change

       If using a cipher from a provider the EVP_CIPH_FLAG_LENGTH_BITS flag can only  be  set  after
       the  cipher  has  been assigned to the cipher context.  See "FLAGS" in EVP_EncryptInit(3) for
       more information.

       Validation of operation context parameters

       Due to move of the implementation of cryptographic operations to the providers, validation of
       various operation parameters can be postponed until the actual operation  is  executed  where
       previously it happened immediately when an operation parameter was set.

       For  example  when setting an unsupported curve with EVP_PKEY_CTX_set_ec_paramgen_curve_nid()
       this function call will not fail but later keygen operations with the EVP_PKEY_CTX will fail.

       Removal of function code from the error codes

       The function code part of the error code is  now  always  set  to  0.  For  that  reason  the
       ERR_GET_FUNC()  macro  was  removed. Applications must resolve the error codes only using the
       library number and the reason code.

       ChaCha20-Poly1305 cipher does not allow a truncated IV length to be used

       In OpenSSL 3.0 setting the IV length to any value other than 12  will  result  in  an  error.
       Prior  to  OpenSSL  3.0  the  ivlen  could be smaller that the required 12 byte length, using
       EVP_CIPHER_CTX_ctrl(ctx, EVP_CRTL_AEAD_SET_IVLEN, ivlen, NULL). This resulted in an  IV  that
       had leading zero padding.

   Installation and Compilation
       Please refer to the INSTALL.md file in the top of the distribution for instructions on how to
       build and install OpenSSL 3.0. Please also refer to the various platform specific NOTES files
       for your specific platform.

   Upgrading from OpenSSL 1.1.1
       Upgrading  to  OpenSSL  3.0  from OpenSSL 1.1.1 should be relatively straight forward in most
       cases. The most likely area where you will encounter problems is if you have used  low  level
       APIs  in  your  code  (as  discussed  above).  In  that  case  you are likely to start seeing
       deprecation warnings when compiling your application. If this happens you have 3 options:

       1.  Ignore the warnings. They are just warnings. The deprecated functions are  still  present
           and  you  may  still  use  them.  However be aware that they may be removed from a future
           version of OpenSSL.

       2.  Suppress the warnings. Refer to your compiler documentation on how to do this.

       3.  Remove your usage of the low level APIs. In this case you will need to rewrite your  code
           to use the high level APIs instead

       Error code changes

       As  OpenSSL  3.0  provides a brand new Encoder/Decoder mechanism for working with widely used
       file formats, application code that checks for particular error reason codes on  key  loading
       failures might need an update.

       Password-protected  keys may deserve special attention. If only some errors are treated as an
       indicator that the user should be asked about the password again, it's  worth  testing  these
       scenarios and processing the newly relevant codes.

       There may be more cases to treat specially, depending on the calling application code.

   Upgrading from OpenSSL 1.0.2
       Upgrading  to OpenSSL 3.0 from OpenSSL 1.0.2 is likely to be significantly more difficult. In
       addition to the issues discussed above in the section about "Upgrading from  OpenSSL  1.1.1",
       the main things to be aware of are:

       1.  The build and installation procedure has changed significantly.

           Check the file INSTALL.md in the top of the installation for instructions on how to build
           and  install  OpenSSL  for  your  platform. Also read the various NOTES files in the same
           directory, as applicable for your platform.

       2.  Many structures have been made opaque in OpenSSL 3.0.

           The structure definitions have been removed from the public header  files  and  moved  to
           internal  header files. In practice this means that you can no longer stack allocate some
           structures. Instead they must be heap allocated through  some  function  call  (typically
           those  function  names have a "_new" suffix to them).  Additionally you must use "setter"
           or "getter" functions to access the fields within those structures.

           For example code that previously looked like this:

            EVP_MD_CTX md_ctx;

            /* This line will now generate compiler errors */
            EVP_MD_CTX_init(&md_ctx);

           The code needs to be amended to look like this:

            EVP_MD_CTX *md_ctx;

            md_ctx = EVP_MD_CTX_new();
            ...
            ...
            EVP_MD_CTX_free(md_ctx);

       3.  Support for TLSv1.3 has been added.

           This has a  number  of  implications  for  SSL/TLS  applications.  See  the  TLS1.3  page
           <https://wiki.openssl.org/index.php/TLS1.3> for further details.

       More details about the breaking changes between OpenSSL versions 1.0.2 and 1.1.0 can be found
       on the OpenSSL 1.1.0 Changes page <https://wiki.openssl.org/index.php/OpenSSL_1.1.0_Changes>.

       Upgrading from the OpenSSL 2.0 FIPS Object Module

       The  OpenSSL  2.0  FIPS Object Module was a separate download that had to be built separately
       and then integrated into your main OpenSSL 1.0.2 build.  In OpenSSL 3.0 the FIPS  support  is
       fully  integrated  into the mainline version of OpenSSL and is no longer a separate download.
       For further information see "Completing the installation of the FIPS Module".

       The function calls FIPS_mode() and FIPS_mode_set() have been removed from  OpenSSL  3.0.  You
       should    rewrite   your   application   to   not   use   them.    See   fips_module(7)   and
       OSSL_PROVIDER-FIPS(7) for details.

   Completing the installation of the FIPS Module
       The FIPS Module  will  be  built  and  installed  automatically  if  FIPS  support  has  been
       configured.    The    current    documentation    can    be    found   in   the   README-FIPS
       <https://github.com/openssl/openssl/blob/master/README-FIPS.md> file.

   Programming
       Applications written to work with OpenSSL 1.1.1 will  mostly  just  work  with  OpenSSL  3.0.
       However  changes  will  be required if you want to take advantage of some of the new features
       that OpenSSL 3.0 makes available. In order to  do  that  you  need  to  understand  some  new
       concepts  introduced  in  OpenSSL  3.0.   Read  "Library  contexts"  in crypto(7) for further
       information.

       Library Context

       A library context allows different  components  of  a  complex  application  to  each  use  a
       different  library  context  and have different providers loaded with different configuration
       settings.  See "Library contexts" in crypto(7) for further info.

       If the user creates an OSSL_LIB_CTX via OSSL_LIB_CTX_new(3) then many functions may  need  to
       be changed to pass additional parameters to handle the library context.

       Using a Library Context - Old functions that should be changed

       If  a  library context is needed then all EVP_* digest functions that return a const EVP_MD *
       such as EVP_sha256() should be replaced  with  a  call  to  EVP_MD_fetch(3).  See  "ALGORITHM
       FETCHING" in crypto(7).

       If a library context is needed then all EVP_* cipher functions that return a const EVP_CIPHER
       *  such  as  EVP_aes_128_cbc()  should  be  replaced  vith a call to EVP_CIPHER_fetch(3). See
       "ALGORITHM FETCHING" in crypto(7).

       Some functions can be passed an object that has already been set up with  a  library  context
       such  as  d2i_X509(3),  d2i_X509_CRL(3),  d2i_X509_REQ(3)  and d2i_X509_PUBKEY(3). If NULL is
       passed instead then the created object will be set up with the default library  context.  Use
       X509_new_ex(3), X509_CRL_new_ex(3), X509_REQ_new_ex(3) and X509_PUBKEY_new_ex(3) if a library
       context is required.

       All  functions  listed  below  with  a  NAME  have  a replacement function NAME_ex that takes
       OSSL_LIB_CTX as an additional argument. Functions that have other mappings are  listed  along
       with the respective name.

       •   ASN1_item_new(3),     ASN1_item_d2i(3),     ASN1_item_d2i_fp(3),    ASN1_item_d2i_bio(3),
           ASN1_item_sign(3) and ASN1_item_verify(3)

       •   BIO_new(3)

       •   b2i_RSA_PVK_bio() and i2b_PVK_bio()

       •   BN_CTX_new(3) and BN_CTX_secure_new(3)

       •   CMS_AuthEnvelopedData_create(3),       CMS_ContentInfo_new(3),        CMS_data_create(3),
           CMS_digest_create(3),            CMS_EncryptedData_encrypt(3),            CMS_encrypt(3),
           CMS_EnvelopedData_create(3), CMS_ReceiptRequest_create0(3) and CMS_sign(3)

       •   CONF_modules_load_file(3)

       •   CTLOG_new(3), CTLOG_new_from_base64(3) and CTLOG_STORE_new(3)

       •   CT_POLICY_EVAL_CTX_new(3)

       •   d2i_AutoPrivateKey(3), d2i_PrivateKey(3) and d2i_PUBKEY(3)

       •   d2i_PrivateKey_bio(3) and d2i_PrivateKey_fp(3)

           Use d2i_PrivateKey_ex_bio(3) and d2i_PrivateKey_ex_fp(3)

       •   EC_GROUP_new(3)

           Use EC_GROUP_new_by_curve_name_ex(3) or EC_GROUP_new_from_params(3).

       •   EVP_DigestSignInit(3) and EVP_DigestVerifyInit(3)

       •   EVP_PBE_CipherInit(3), EVP_PBE_find(3) and EVP_PBE_scrypt(3)

       •   PKCS5_PBE_keyivgen(3)

       •   EVP_PKCS82PKEY(3)

       •   EVP_PKEY_CTX_new_id(3)

           Use EVP_PKEY_CTX_new_from_name(3)

       •   EVP_PKEY_derive_set_peer(3),             EVP_PKEY_new_raw_private_key(3)              and
           EVP_PKEY_new_raw_public_key(3)

       •   EVP_SignFinal(3) and EVP_VerifyFinal(3)

       •   NCONF_new(3)

       •   OCSP_RESPID_match(3) and OCSP_RESPID_set_by_key(3)

       •   OPENSSL_thread_stop(3)

       •   OSSL_STORE_open(3)

       •   PEM_read_bio_Parameters(3),      PEM_read_bio_PrivateKey(3),      PEM_read_bio_PUBKEY(3),
           PEM_read_PrivateKey(3) and PEM_read_PUBKEY(3)

       •   PEM_write_bio_PrivateKey(3),   PEM_write_bio_PUBKEY(3),    PEM_write_PrivateKey(3)    and
           PEM_write_PUBKEY(3)

       •   PEM_X509_INFO_read_bio(3) and PEM_X509_INFO_read(3)

       •   PKCS12_add_key(3),     PKCS12_add_safe(3),     PKCS12_add_safes(3),     PKCS12_create(3),
           PKCS12_decrypt_skey(3),            PKCS12_init(3),            PKCS12_item_decrypt_d2i(3),
           PKCS12_item_i2d_encrypt(3),         PKCS12_key_gen_asc(3),         PKCS12_key_gen_uni(3),
           PKCS12_key_gen_utf8(3),          PKCS12_pack_p7encdata(3),           PKCS12_pbe_crypt(3),
           PKCS12_PBE_keyivgen(3), PKCS12_SAFEBAG_create_pkcs8_encrypt(3)

       •   PKCS5_pbe_set0_algor(3),  PKCS5_pbe_set(3), PKCS5_pbe2_set_iv(3), PKCS5_pbkdf2_set(3) and
           PKCS5_v2_scrypt_keyivgen(3)

       •   PKCS7_encrypt(3), PKCS7_new(3) and PKCS7_sign(3)

       •   PKCS8_decrypt(3), PKCS8_encrypt(3) and PKCS8_set0_pbe(3)

       •   RAND_bytes(3) and RAND_priv_bytes(3)

       •   SMIME_write_ASN1(3)

       •   SSL_load_client_CA_file(3)

       •   SSL_CTX_new(3)

       •   TS_RESP_CTX_new(3)

       •   X509_CRL_new(3)

       •   X509_load_cert_crl_file(3) and X509_load_cert_file(3)

       •   X509_LOOKUP_by_subject(3) and X509_LOOKUP_ctrl(3)

       •   X509_NAME_hash(3)

       •   X509_new(3)

       •   X509_REQ_new(3) and X509_REQ_verify(3)

       •   X509_STORE_CTX_new(3),     X509_STORE_set_default_paths(3),      X509_STORE_load_file(3),
           X509_STORE_load_locations(3) and X509_STORE_load_store(3)

       New functions that use a Library context

       The  following  functions can be passed a library context if required.  Passing NULL will use
       the default library context.

       •   BIO_new_from_core_bio(3)

       •   EVP_ASYM_CIPHER_fetch(3) and EVP_ASYM_CIPHER_do_all_provided(3)

       •   EVP_CIPHER_fetch(3) and EVP_CIPHER_do_all_provided(3)

       •   EVP_default_properties_enable_fips(3) and EVP_default_properties_is_fips_enabled(3)

       •   EVP_KDF_fetch(3) and EVP_KDF_do_all_provided(3)

       •   EVP_KEM_fetch(3) and EVP_KEM_do_all_provided(3)

       •   EVP_KEYEXCH_fetch(3) and EVP_KEYEXCH_do_all_provided(3)

       •   EVP_KEYMGMT_fetch(3) and EVP_KEYMGMT_do_all_provided(3)

       •   EVP_MAC_fetch(3) and EVP_MAC_do_all_provided(3)

       •   EVP_MD_fetch(3) and EVP_MD_do_all_provided(3)

       •   EVP_PKEY_CTX_new_from_pkey(3)

       •   EVP_PKEY_Q_keygen(3)

       •   EVP_Q_mac(3) and EVP_Q_digest(3)

       •   EVP_RAND(3) and EVP_RAND_do_all_provided(3)

       •   EVP_set_default_properties(3)

       •   EVP_SIGNATURE_fetch(3) and EVP_SIGNATURE_do_all_provided(3)

       •   OSSL_CMP_CTX_new(3) and OSSL_CMP_SRV_CTX_new(3)

       •   OSSL_CRMF_ENCRYPTEDVALUE_get1_encCert(3)

       •   OSSL_CRMF_MSG_create_popo(3) and OSSL_CRMF_MSGS_verify_popo(3)

       •   OSSL_CRMF_pbm_new(3) and OSSL_CRMF_pbmp_new(3)

       •   OSSL_DECODER_CTX_add_extra(3) and OSSL_DECODER_CTX_new_for_pkey(3)

       •   OSSL_DECODER_fetch(3) and OSSL_DECODER_do_all_provided(3)

       •   OSSL_ENCODER_CTX_add_extra(3)

       •   OSSL_ENCODER_fetch(3) and OSSL_ENCODER_do_all_provided(3)

       •   OSSL_LIB_CTX_free(3), OSSL_LIB_CTX_load_config(3) and OSSL_LIB_CTX_set0_default(3)

       •   OSSL_PROVIDER_add_builtin(3),    OSSL_PROVIDER_available(3),     OSSL_PROVIDER_do_all(3),
           OSSL_PROVIDER_load(3),            OSSL_PROVIDER_set_default_search_path(3)            and
           OSSL_PROVIDER_try_load(3)

       •   OSSL_SELF_TEST_get_callback(3) and OSSL_SELF_TEST_set_callback(3)

       •   OSSL_STORE_attach(3)

       •   OSSL_STORE_LOADER_fetch(3) and OSSL_STORE_LOADER_do_all_provided(3)

       •   RAND_get0_primary(3),  RAND_get0_private(3),  RAND_get0_public(3),  RAND_set_DRBG_type(3)
           and RAND_set_seed_source_type(3)

       Providers

       Providers  are  described  in  detail  here  "Providers"  in  crypto(7).   See  also "OPENSSL
       PROVIDERS" in crypto(7).

       Fetching algorithms and property queries

       Implicit and Explicit Fetching is described in detail here "ALGORITHM FETCHING" in crypto(7).

       Mapping EVP controls and flags to provider OSSL_PARAM(3) parameters

       The existing functions for controls (such as EVP_CIPHER_CTX_ctrl(3)) and  manipulating  flags
       (such  as  EVP_MD_CTX_set_flags(3))internally  use  OSSL_PARAMS  to  pass information to/from
       provider objects.  See OSSL_PARAM(3) for additional information related to parameters.

       For  ciphers  see  "CONTROLS"  in  EVP_EncryptInit(3),  "FLAGS"  in  EVP_EncryptInit(3)   and
       "PARAMETERS" in EVP_EncryptInit(3).

       For   digests   see   "CONTROLS"  in  EVP_DigestInit(3),  "FLAGS"  in  EVP_DigestInit(3)  and
       "PARAMETERS" in EVP_DigestInit(3).

       Deprecation of Low Level Functions

       A significant number of APIs have been deprecated in OpenSSL  3.0.   This  section  describes
       some  common  categories of deprecations.  See "Deprecated function mappings" for the list of
       deprecated functions that refer to these categories.

       Providers are a replacement for engines and low-level method overrides

       Any  accessor  that  uses  an  ENGINE  is  deprecated   (such   as   EVP_PKEY_set1_engine()).
       Applications using engines should instead use providers.

       Before  providers  were  added  algorithms  were  overridden  by changing the methods used by
       algorithms. All these methods such as RSA_new_method() and RSA_meth_new() are now  deprecated
       and can be replaced by using providers instead.

       Deprecated i2d and d2i functions for low-level key types

       Any  i2d  and  d2i  functions such as d2i_DHparams() that take a low-level key type have been
       deprecated. Applications should instead use the OSSL_DECODER(3) and OSSL_ENCODER(3)  APIs  to
       read and write files.  See "Migration" in d2i_RSAPrivateKey(3) for further details.

       Deprecated low-level key object getters and setters

       Applications   that  set  or  get  low-level  key  objects  (such  as  EVP_PKEY_set1_DH()  or
       EVP_PKEY_get0())  should  instead  use  the  OSSL_ENCODER  (See  OSSL_ENCODER_to_bio(3))   or
       OSSL_DECODER  (See  OSSL_DECODER_from_bio(3)) APIs, or alternatively use EVP_PKEY_fromdata(3)
       or EVP_PKEY_todata(3).

       Deprecated low-level key parameter getters

       Functions that access low-level objects directly such as RSA_get0_n(3)  are  now  deprecated.
       Applications   should   use   one   of  EVP_PKEY_get_bn_param(3),  EVP_PKEY_get_int_param(3),
       l<EVP_PKEY_get_size_t_param(3)>,                           EVP_PKEY_get_utf8_string_param(3),
       EVP_PKEY_get_octet_string_param(3)   or  EVP_PKEY_get_params(3)  to  access  fields  from  an
       EVP_PKEY.  Gettable parameters are listed in "Common RSA parameters" in EVP_PKEY-RSA(7),  "DH
       parameters"  in  EVP_PKEY-DH(7),  "DSA  parameters"  in  EVP_PKEY-DSA(7), "FFC parameters" in
       EVP_PKEY-FFC(7), "Common EC parameters" in EVP_PKEY-EC(7) and "Common X25519,  X448,  ED25519
       and ED448 parameters" in EVP_PKEY-X25519(7).  Applications may also use EVP_PKEY_todata(3) to
       return all fields.

       Deprecated low-level key parameter setters

       Functions  that  access  low-level  objects  directly  such as RSA_set0_crt_params(3) are now
       deprecated. Applications should  use  EVP_PKEY_fromdata(3)  to  create  new  keys  from  user
       provided  key  data.  Keys should be immutable once they are created, so if required the user
       may  use  EVP_PKEY_todata(3),  OSSL_PARAM_merge(3),  and  EVP_PKEY_fromdata(3)  to  create  a
       modified  key.   See "Examples" in EVP_PKEY-DH(7) for more information.  See "Deprecated low-
       level key generation functions" for information on generating a key using parameters.

       Deprecated low-level object creation

       Low-level  objects  were  created  using  methods  such  as  RSA_new(3),  RSA_up_ref(3)   and
       RSA_free(3).   Applications   should   instead   use   the  high-level  EVP_PKEY  APIs,  e.g.
       EVP_PKEY_new(3),      EVP_PKEY_up_ref(3)      and      EVP_PKEY_free(3).       See       also
       EVP_PKEY_CTX_new_from_name(3) and EVP_PKEY_CTX_new_from_pkey(3).

       EVP_PKEYs  may be created in a variety of ways: See also "Deprecated low-level key generation
       functions", "Deprecated low-level key reading and writing  functions"  and  "Deprecated  low-
       level key parameter setters".

       Deprecated low-level encryption functions

       Low-level encryption functions such as AES_encrypt(3) and AES_decrypt(3) have been informally
       discouraged from use for a long time. Applications should instead use the high level EVP APIs
       EVP_EncryptInit_ex(3),      EVP_EncryptUpdate(3),      and      EVP_EncryptFinal_ex(3)     or
       EVP_DecryptInit_ex(3), EVP_DecryptUpdate(3) and EVP_DecryptFinal_ex(3).

       Deprecated low-level digest functions

       Use of low-level digest functions such as SHA1_Init(3) have been informally discouraged  from
       use  for  a  long  time.   Applications  should  instead  use  the  the  high  level EVP APIs
       EVP_DigestInit_ex(3), EVP_DigestUpdate(3) and EVP_DigestFinal_ex(3), or  the  quick  one-shot
       EVP_Q_digest(3).

       Note  that  the functions SHA1(3), SHA224(3), SHA256(3), SHA384(3) and SHA512(3) have changed
       to macros that use EVP_Q_digest(3).

       Deprecated low-level signing functions

       Use of low-level signing functions such as DSA_sign(3) have been informally discouraged for a
       long time. Instead applications should use EVP_DigestSign(3)  and  EVP_DigestVerify(3).   See
       also      EVP_SIGNATURE-RSA(7),      EVP_SIGNATURE-DSA(7),     EVP_SIGNATURE-ECDSA(7)     and
       EVP_SIGNATURE-ED25519(7).

       Deprecated low-level MAC functions

       Low-level mac functions such as CMAC_Init(3) are deprecated.  Applications should instead use
       the new EVP_MAC(3) interface, using EVP_MAC_CTX_new(3), EVP_MAC_CTX_free(3), EVP_MAC_init(3),
       EVP_MAC_update(3) and EVP_MAC_final(3) or the single-shot  MAC  function  EVP_Q_mac(3).   See
       EVP_MAC(3),     EVP_MAC-HMAC(7),     EVP_MAC-CMAC(7),    EVP_MAC-GMAC(7),    EVP_MAC-KMAC(7),
       EVP_MAC-BLAKE2(7), EVP_MAC-Poly1305(7) and EVP_MAC-Siphash(7) for additional information.

       Note that the one-shot method HMAC() is still available for compatibility purposes, but  this
       can also be replaced by using EVP_Q_MAC if a library context is required.

       Deprecated low-level validation functions

       Low-level  validation functions such as DH_check(3) have been informally discouraged from use
       for a long time. Applications should  instead  use  the  high-level  EVP_PKEY  APIs  such  as
       EVP_PKEY_check(3),           EVP_PKEY_param_check(3),          EVP_PKEY_param_check_quick(3),
       EVP_PKEY_public_check(3),  EVP_PKEY_public_check_quick(3),   EVP_PKEY_private_check(3),   and
       EVP_PKEY_pairwise_check(3).

       Deprecated low-level key exchange functions

       Many  low-level  functions  have  been  informally  discouraged  from  use  for  a long time.
       Applications    should    instead    use    EVP_PKEY_derive(3).     See    EVP_KEYEXCH-DH(7),
       EVP_KEYEXCH-ECDH(7) and EVP_KEYEXCH-X25519(7).

       Deprecated low-level key generation functions

       Many  low-level  functions  have  been  informally  discouraged  from  use  for  a long time.
       Applications should instead use EVP_PKEY_keygen_init(3) and EVP_PKEY_generate(3) as described
       in EVP_PKEY-DSA(7), EVP_PKEY-DH(7), EVP_PKEY-RSA(7), EVP_PKEY-EC(7)  and  EVP_PKEY-X25519(7).
       The  'quick'  one-shot  function  EVP_PKEY_Q_keygen(3)  and macros for the most common cases:
       <EVP_RSA_gen(3)> and EVP_EC_gen(3) may also be used.

       Deprecated low-level key reading and writing functions

       Use of low-level objects (such as DSA) has been informally discouraged from use  for  a  long
       time.  Functions  to  read  and write these low-level objects (such as PEM_read_DSA_PUBKEY())
       should  be   replaced.   Applications   should   instead   use   OSSL_ENCODER_to_bio(3)   and
       OSSL_DECODER_from_bio(3).

       Deprecated low-level key printing functions

       Use  of  low-level  objects (such as DSA) has been informally discouraged from use for a long
       time. Functions to print these low-level objects such as DSA_print() should be replaced  with
       the  equivalent  EVP_PKEY functions.  Application should use one of EVP_PKEY_print_public(3),
       EVP_PKEY_print_private(3),       EVP_PKEY_print_params(3),       EVP_PKEY_print_public_fp(3),
       EVP_PKEY_print_private_fp(3)  or  EVP_PKEY_print_params_fp(3). Note that internally these use
       OSSL_ENCODER_to_bio(3) and OSSL_DECODER_from_bio(3).

       Deprecated function mappings

       The following functions have been deprecated in 3.0.

       •   AES_bi_ige_encrypt() and AES_ige_encrypt()

           There is no replacement for the IGE functions. New  code  should  not  use  these  modes.
           These  undocumented functions were never integrated into the EVP layer.  They implemented
           the AES Infinite Garble Extension (IGE) mode and AES Bi-directional IGE mode. These modes
           were never formally standardised and usage of these functions  is  believed  to  be  very
           small.  In  particular  AES_bi_ige_encrypt()  has a known bug. It accepts 2 AES keys, but
           only one is ever used. The security implications are believed to  be  minimal,  but  this
           issue was never fixed for backwards compatibility reasons.

       •   AES_encrypt(),      AES_decrypt(),      AES_set_encrypt_key(),     AES_set_decrypt_key(),
           AES_cbc_encrypt(),    AES_cfb128_encrypt(),    AES_cfb1_encrypt(),    AES_cfb8_encrypt(),
           AES_ecb_encrypt(), AES_ofb128_encrypt()

       •   AES_unwrap_key(), AES_wrap_key()

           See "Deprecated low-level encryption functions"

       •   AES_options()

           There is no replacement. It returned a string indicating if the AES code was unrolled.

       •   ASN1_digest(), ASN1_sign(), ASN1_verify()

           There  are  no replacements. These old functions are not used, and could be disabled with
           the macro NO_ASN1_OLD since OpenSSL 0.9.7.

       •   ASN1_STRING_length_set()

           Use ASN1_STRING_set(3) or ASN1_STRING_set0(3) instead.  This  was  a  potentially  unsafe
           function that could change the bounds of a previously passed in pointer.

       •   BF_encrypt(),    BF_decrypt(),    BF_set_key(),   BF_cbc_encrypt(),   BF_cfb64_encrypt(),
           BF_ecb_encrypt(), BF_ofb64_encrypt()

           See "Deprecated low-level encryption functions".  The Blowfish algorithm has  been  moved
           to the Legacy Provider.

       •   BF_options()

           There is no replacement. This option returned a constant string.

       •   BIO_get_callback(), BIO_set_callback(), BIO_debug_callback()

           Use the respective non-deprecated _ex() functions.

       •   BN_is_prime_ex(), BN_is_prime_fasttest_ex()

           Use  BN_check_prime(3) which avoids possible misuse and always uses at least 64 rounds of
           the Miller-Rabin primality test.

       •   BN_pseudo_rand(), BN_pseudo_rand_range()

           Use BN_rand(3) and BN_rand_range(3).

       •   BN_X931_derive_prime_ex(), BN_X931_generate_prime_ex(), BN_X931_generate_Xpq()

           There are no replacements for these low-level functions. They  were  used  internally  by
           RSA_X931_derive_ex()  and  RSA_X931_generate_key_ex()  which  are  also  deprecated.  Use
           EVP_PKEY_keygen(3) instead.

       •   Camellia_encrypt(),   Camellia_decrypt(),   Camellia_set_key(),   Camellia_cbc_encrypt(),
           Camellia_cfb128_encrypt(),        Camellia_cfb1_encrypt(),       Camellia_cfb8_encrypt(),
           Camellia_ctr128_encrypt(), Camellia_ecb_encrypt(), Camellia_ofb128_encrypt()

           See "Deprecated low-level encryption functions".

       •   CAST_encrypt(), CAST_decrypt(), CAST_set_key(), CAST_cbc_encrypt(), CAST_cfb64_encrypt(),
           CAST_ecb_encrypt(), CAST_ofb64_encrypt()

           See "Deprecated low-level encryption functions".  The CAST algorithm has  been  moved  to
           the Legacy Provider.

       •   CMAC_CTX_new(),        CMAC_CTX_cleanup(),        CMAC_CTX_copy(),       CMAC_CTX_free(),
           CMAC_CTX_get0_cipher_ctx()

           See "Deprecated low-level MAC functions".

       •   CMAC_Init(), CMAC_Update(), CMAC_Final(), CMAC_resume()

           See "Deprecated low-level MAC functions".

       •   CRYPTO_mem_ctrl(),          CRYPTO_mem_debug_free(),           CRYPTO_mem_debug_malloc(),
           CRYPTO_mem_debug_pop(),        CRYPTO_mem_debug_push(),       CRYPTO_mem_debug_realloc(),
           CRYPTO_mem_leaks(), CRYPTO_mem_leaks_cb(), CRYPTO_mem_leaks_fp(), CRYPTO_set_mem_debug()

           Memory-leak checking has been deprecated in favor of more modern development tools,  such
           as compiler memory and leak sanitizers or Valgrind.

       •   CRYPTO_cts128_encrypt_block(),   CRYPTO_cts128_encrypt(),  CRYPTO_cts128_decrypt_block(),
           CRYPTO_cts128_decrypt(), CRYPTO_nistcts128_encrypt_block(),  CRYPTO_nistcts128_encrypt(),
           CRYPTO_nistcts128_decrypt_block(), CRYPTO_nistcts128_decrypt()

           Use   the   higher   level   functions   EVP_CipherInit_ex2(),   EVP_CipherUpdate()   and
           EVP_CipherFinal_ex() instead.  See the "cts_mode" parameter  in  "Gettable  and  Settable
           EVP_CIPHER_CTX  parameters"  in EVP_EncryptInit(3).  See "EXAMPLES" in EVP_EncryptInit(3)
           for a AES-256-CBC-CTS example.

       •   d2i_DHparams(),       d2i_DHxparams(),       d2i_DSAparams(),        d2i_DSAPrivateKey(),
           d2i_DSAPrivateKey_bio(),  d2i_DSAPrivateKey_fp(), d2i_DSA_PUBKEY(), d2i_DSA_PUBKEY_bio(),
           d2i_DSA_PUBKEY_fp(),    d2i_DSAPublicKey(),    d2i_ECParameters(),    d2i_ECPrivateKey(),
           d2i_ECPrivateKey_bio(),   d2i_ECPrivateKey_fp(),   d2i_EC_PUBKEY(),  d2i_EC_PUBKEY_bio(),
           d2i_EC_PUBKEY_fp(),  o2i_ECPublicKey(),   d2i_RSAPrivateKey(),   d2i_RSAPrivateKey_bio(),
           d2i_RSAPrivateKey_fp(),   d2i_RSA_PUBKEY(),   d2i_RSA_PUBKEY_bio(),  d2i_RSA_PUBKEY_fp(),
           d2i_RSAPublicKey(), d2i_RSAPublicKey_bio(), d2i_RSAPublicKey_fp()

           See "Deprecated i2d and d2i functions for low-level key types"

       •   DES_crypt(),    DES_fcrypt(),     DES_encrypt1(),     DES_encrypt2(),     DES_encrypt3(),
           DES_decrypt3(),             DES_ede3_cbc_encrypt(),             DES_ede3_cfb64_encrypt(),
           DES_ede3_cfb_encrypt(),DES_ede3_ofb64_encrypt(),  DES_ecb_encrypt(),  DES_ecb3_encrypt(),
           DES_ofb64_encrypt(),      DES_ofb_encrypt(),     DES_cfb64_encrypt     DES_cfb_encrypt(),
           DES_cbc_encrypt(),    DES_ncbc_encrypt(),     DES_pcbc_encrypt(),     DES_xcbc_encrypt(),
           DES_cbc_cksum(),     DES_quad_cksum(),     DES_check_key_parity(),     DES_is_weak_key(),
           DES_key_sched(), DES_options(), DES_random_key(),  DES_set_key(),  DES_set_key_checked(),
           DES_set_key_unchecked(), DES_set_odd_parity(), DES_string_to_2keys(), DES_string_to_key()

           See  "Deprecated  low-level encryption functions".  Algorithms for "DESX-CBC", "DES-ECB",
           "DES-CBC", "DES-OFB", "DES-CFB", "DES-CFB1" and "DES-CFB8" have been moved to the  Legacy
           Provider.

       •   DH_bits(), DH_security_bits(), DH_size()

           Use EVP_PKEY_get_bits(3), EVP_PKEY_get_security_bits(3) and EVP_PKEY_get_size(3).

       •   DH_check(),  DH_check_ex(),  DH_check_params(), DH_check_params_ex(), DH_check_pub_key(),
           DH_check_pub_key_ex()

           See "Deprecated low-level validation functions"

       •   DH_clear_flags(), DH_test_flags(), DH_set_flags()

           The  DH_FLAG_CACHE_MONT_P  flag   has   been   deprecated   without   replacement.    The
           DH_FLAG_TYPE_DH  and  DH_FLAG_TYPE_DHX  have  been  deprecated.   Use  EVP_PKEY_is_a() to
           determine the type of a key.  There is no replacement for setting these flags.

       •   DH_compute_key() DH_compute_key_padded()

           See "Deprecated low-level key exchange functions".

       •   DH_new(), DH_new_by_nid(), DH_free(), DH_up_ref()

           See "Deprecated low-level object creation"

       •   DH_generate_key(), DH_generate_parameters_ex()

           See "Deprecated low-level key generation functions".

       •   DH_get0_pqg(), DH_get0_p(), DH_get0_q(), DH_get0_g(), DH_get0_key(),  DH_get0_priv_key(),
           DH_get0_pub_key(), DH_get_length(), DH_get_nid()

           See "Deprecated low-level key parameter getters"

       •   DH_get_1024_160(), DH_get_2048_224(), DH_get_2048_256()

           Applications  should  instead  set  the  OSSL_PKEY_PARAM_GROUP_NAME  as  specified in "DH
           parameters" in EVP_PKEY-DH(7)) to one of "dh_1024_160",  "dh_2048_224"  or  "dh_2048_256"
           when generating a DH key.

       •   DH_KDF_X9_42()

           Applications should use EVP_PKEY_CTX_set_dh_kdf_type(3) instead.

       •   DH_get_default_method(),  DH_get0_engine(),  DH_meth_*(),  DH_new_method(), DH_OpenSSL(),
           DH_get_ex_data(), DH_set_default_method(), DH_set_method(), DH_set_ex_data()

           See "Providers are a replacement for engines and low-level method overrides"

       •   DHparams_print(), DHparams_print_fp()

           See "Deprecated low-level key printing functions"

       •   DH_set0_key(), DH_set0_pqg(), DH_set_length()

           See "Deprecated low-level key parameter setters"

       •   DSA_bits(), DSA_security_bits(), DSA_size()

           Use EVP_PKEY_get_bits(3), EVP_PKEY_get_security_bits(3) and EVP_PKEY_get_size(3).

       •   DHparams_dup(), DSA_dup_DH()

           There is no direct replacement.  Applications  may  use  EVP_PKEY_copy_parameters(3)  and
           EVP_PKEY_dup(3) instead.

       •   DSA_generate_key(), DSA_generate_parameters_ex()

           See "Deprecated low-level key generation functions".

       •   DSA_get0_engine(),    DSA_get_default_method(),    DSA_get_ex_data(),   DSA_get_method(),
           DSA_meth_*(),      DSA_new_method(),       DSA_OpenSSL(),       DSA_set_default_method(),
           DSA_set_ex_data(), DSA_set_method()

           See "Providers are a replacement for engines and low-level method overrides".

       •   DSA_get0_p(),     DSA_get0_q(),     DSA_get0_g(),     DSA_get0_pqg(),     DSA_get0_key(),
           DSA_get0_priv_key(), DSA_get0_pub_key()

           See "Deprecated low-level key parameter getters".

       •   DSA_new(), DSA_free(), DSA_up_ref()

           See "Deprecated low-level object creation"

       •   DSAparams_dup()

           There is no direct replacement.  Applications  may  use  EVP_PKEY_copy_parameters(3)  and
           EVP_PKEY_dup(3) instead.

       •   DSAparams_print(), DSAparams_print_fp(), DSA_print(), DSA_print_fp()

           See "Deprecated low-level key printing functions"

       •   DSA_set0_key(), DSA_set0_pqg()

           See "Deprecated low-level key parameter setters"

       •   DSA_set_flags(), DSA_clear_flags(), DSA_test_flags()

           The DSA_FLAG_CACHE_MONT_P flag has been deprecated without replacement.

       •   DSA_sign(), DSA_do_sign(), DSA_sign_setup(), DSA_verify(), DSA_do_verify()

           See "Deprecated low-level signing functions".

       •   ECDH_compute_key()

           See "Deprecated low-level key exchange functions".

       •   ECDH_KDF_X9_62()

           Applications     may     either     set     this     using     the     helper    function
           EVP_PKEY_CTX_set_ecdh_kdf_type(3) or by setting an OSSL_PARAM(3) using the "kdf-type"  as
           shown in "EXAMPLES" in EVP_KEYEXCH-ECDH(7)

       •   ECDSA_sign(),  ECDSA_sign_ex(),  ECDSA_sign_setup(), ECDSA_do_sign(), ECDSA_do_sign_ex(),
           ECDSA_verify(), ECDSA_do_verify()

           See "Deprecated low-level signing functions".

       •   ECDSA_size()

           Applications should use EVP_PKEY_get_size(3).

       •   EC_GF2m_simple_method(),           EC_GFp_mont_method(),            EC_GFp_nist_method(),
           EC_GFp_nistp224_method(),       EC_GFp_nistp256_method(),       EC_GFp_nistp521_method(),
           EC_GFp_simple_method()

           There are no replacements for these functions. Applications should rely  on  the  library
           automatically assigning a suitable method internally when an EC_GROUP is constructed.

       •   EC_GROUP_clear_free()

           Use EC_GROUP_free(3) instead.

       •   EC_GROUP_get_curve_GF2m(),      EC_GROUP_get_curve_GFp(),      EC_GROUP_set_curve_GF2m(),
           EC_GROUP_set_curve_GFp()

           Applications should use EC_GROUP_get_curve(3) and EC_GROUP_set_curve(3).

       •   EC_GROUP_have_precompute_mult(), EC_GROUP_precompute_mult(), EC_KEY_precompute_mult()

           These functions are not widely used. Applications should instead switch to  named  curves
           which OpenSSL has hardcoded lookup tables for.

       •   EC_GROUP_new(), EC_GROUP_method_of(), EC_POINT_method_of()

           EC_METHOD is now an internal-only concept and a suitable EC_METHOD is assigned internally
           without  application  intervention.  Users of EC_GROUP_new() should switch to a different
           suitable constructor.

       •   EC_KEY_can_sign()

           Applications should use EVP_PKEY_can_sign(3) instead.

       •   EC_KEY_check_key()

           See "Deprecated low-level validation functions"

       •   EC_KEY_set_flags(), EC_KEY_get_flags(), EC_KEY_clear_flags()

           See "Common EC parameters" in EVP_PKEY-EC(7) which handles flags as  separate  parameters
           for    OSSL_PKEY_PARAM_EC_POINT_CONVERSION_FORMAT,   OSSL_PKEY_PARAM_EC_GROUP_CHECK_TYPE,
           OSSL_PKEY_PARAM_EC_ENCODING,            OSSL_PKEY_PARAM_USE_COFACTOR_ECDH             and
           OSSL_PKEY_PARAM_EC_INCLUDE_PUBLIC.  See also "EXAMPLES" in EVP_PKEY-EC(7)

       •   EC_KEY_dup(), EC_KEY_copy()

           There  is  no  direct  replacement.  Applications may use EVP_PKEY_copy_parameters(3) and
           EVP_PKEY_dup(3) instead.

       •   EC_KEY_decoded_from_explicit_params()

           There is no replacement.

       •   EC_KEY_generate_key()

           See "Deprecated low-level key generation functions".

       •   EC_KEY_get0_group(),         EC_KEY_get0_private_key(),         EC_KEY_get0_public_key(),
           EC_KEY_get_conv_form(), EC_KEY_get_enc_flags()

           See "Deprecated low-level key parameter getters".

       •   EC_KEY_get0_engine(),          EC_KEY_get_default_method(),          EC_KEY_get_method(),
           EC_KEY_new_method(),   EC_KEY_get_ex_data(),   EC_KEY_OpenSSL(),    EC_KEY_set_ex_data(),
           EC_KEY_set_default_method(), EC_KEY_METHOD_*(), EC_KEY_set_method()

           See "Providers are a replacement for engines and low-level method overrides"

       •   EC_METHOD_get_field_type()

           Use EC_GROUP_get_field_type(3) instead.  See "Providers are a replacement for engines and
           low-level method overrides"

       •   EC_KEY_key2buf(),       EC_KEY_oct2key(),      EC_KEY_oct2priv(),      EC_KEY_priv2buf(),
           EC_KEY_priv2oct()

           There are no replacements for these.

       •   EC_KEY_new(), EC_KEY_new_by_curve_name(), EC_KEY_free(), EC_KEY_up_ref()

           See "Deprecated low-level object creation"

       •   EC_KEY_print(), EC_KEY_print_fp()

           See "Deprecated low-level key printing functions"

       •   EC_KEY_set_asn1_flag(), EC_KEY_set_conv_form(), EC_KEY_set_enc_flags()

           See "Deprecated low-level key parameter setters".

       •   EC_KEY_set_group(),          EC_KEY_set_private_key(),           EC_KEY_set_public_key(),
           EC_KEY_set_public_key_affine_coordinates()

           See "Deprecated low-level key parameter setters".

       •   ECParameters_print(),           ECParameters_print_fp(),          ECPKParameters_print(),
           ECPKParameters_print_fp()

           See "Deprecated low-level key printing functions"

       •   EC_POINT_bn2point(), EC_POINT_point2bn()

           These functions were not particularly useful, since EC point  serialization  formats  are
           not individual big-endian integers.

       •   EC_POINT_get_affine_coordinates_GF2m(),            EC_POINT_get_affine_coordinates_GFp(),
           EC_POINT_set_affine_coordinates_GF2m(), EC_POINT_set_affine_coordinates_GFp()

           Applications       should        use        EC_POINT_get_affine_coordinates(3)        and
           EC_POINT_set_affine_coordinates(3) instead.

       •   EC_POINT_get_Jprojective_coordinates_GFp(), EC_POINT_set_Jprojective_coordinates_GFp()

           These   functions   are   not   widely   used.   Applications   should  instead  use  the
           EC_POINT_set_affine_coordinates(3) and EC_POINT_get_affine_coordinates(3) functions.

       •   EC_POINT_make_affine(), EC_POINTs_make_affine()

           There is no replacement. These functions were not widely used, and OpenSSL  automatically
           performs this conversion when needed.

       •   EC_POINT_set_compressed_coordinates_GF2m(), EC_POINT_set_compressed_coordinates_GFp()

           Applications should use EC_POINT_set_compressed_coordinates(3) instead.

       •   EC_POINTs_mul()

           This  function  is  not  widely used. Applications should instead use the EC_POINT_mul(3)
           function.

       •   ENGINE_*()

           All engine functions are deprecated. An engine should be rewritten as  a  provider.   See
           "Providers are a replacement for engines and low-level method overrides".

       •   ERR_load_*(),  ERR_func_error_string(),  ERR_get_error_line(), ERR_get_error_line_data(),
           ERR_get_state()

           OpenSSL now loads error strings automatically so these functions are not needed.

       •   ERR_peek_error_line_data(), ERR_peek_last_error_line_data()

           The    new    functions    are    ERR_peek_error_func(3),    ERR_peek_last_error_func(3),
           ERR_peek_error_data(3),         ERR_peek_last_error_data(3),        ERR_get_error_all(3),
           ERR_peek_error_all(3)   and   ERR_peek_last_error_all(3).    Applications   should    use
           ERR_get_error_all(3),  or  pick  information  with ERR_peek functions and finish off with
           getting the error code by using ERR_get_error(3).

       •   EVP_CIPHER_CTX_iv(), EVP_CIPHER_CTX_iv_noconst(), EVP_CIPHER_CTX_original_iv()

           Applications       should       instead       use       EVP_CIPHER_CTX_get_updated_iv(3),
           EVP_CIPHER_CTX_get_updated_iv(3) and EVP_CIPHER_CTX_get_original_iv(3) respectively.  See
           EVP_CIPHER_CTX_get_original_iv(3) for further information.

       •   EVP_CIPHER_meth_*(), EVP_MD_CTX_set_update_fn(), EVP_MD_CTX_update_fn(), EVP_MD_meth_*()

           See "Providers are a replacement for engines and low-level method overrides".

       •   EVP_PKEY_CTRL_PKCS7_ENCRYPT(), EVP_PKEY_CTRL_PKCS7_DECRYPT(), EVP_PKEY_CTRL_PKCS7_SIGN(),
           EVP_PKEY_CTRL_CMS_ENCRYPT(), EVP_PKEY_CTRL_CMS_DECRYPT(), and EVP_PKEY_CTRL_CMS_SIGN()

           These  control operations are not invoked by the OpenSSL library anymore and are replaced
           by direct checks of the key  operation  against  the  key  type  when  the  operation  is
           initialized.

       •   EVP_PKEY_CTX_get0_dh_kdf_ukm(), EVP_PKEY_CTX_get0_ecdh_kdf_ukm()

           See the "kdf-ukm" item in "DH key exchange parameters" in EVP_KEYEXCH-DH(7) and "ECDH Key
           Exchange parameters" in EVP_KEYEXCH-ECDH(7).  These functions are obsolete and should not
           be required.

       •   EVP_PKEY_CTX_set_rsa_keygen_pubexp()

           Applications should use EVP_PKEY_CTX_set1_rsa_keygen_pubexp(3) instead.

       •   EVP_PKEY_cmp(), EVP_PKEY_cmp_parameters()

           Applications  should  use  EVP_PKEY_eq(3)  and  EVP_PKEY_parameters_eq(3)  instead.   See
           EVP_PKEY_copy_parameters(3) for further details.

       •   EVP_PKEY_encrypt_old(), EVP_PKEY_decrypt_old(),

           Applications   should   use   EVP_PKEY_encrypt_init(3)   and    EVP_PKEY_encrypt(3)    or
           EVP_PKEY_decrypt_init(3) and EVP_PKEY_decrypt(3) instead.

       •   EVP_PKEY_get0()

           This function returns NULL if the key comes from a provider.

       •   EVP_PKEY_get0_DH(),   EVP_PKEY_get0_DSA(),  EVP_PKEY_get0_EC_KEY(),  EVP_PKEY_get0_RSA(),
           EVP_PKEY_get1_DH(), EVP_PKEY_get1_DSA(),  EVP_PKEY_get1_EC_KEY  and  EVP_PKEY_get1_RSA(),
           EVP_PKEY_get0_hmac(), EVP_PKEY_get0_poly1305(), EVP_PKEY_get0_siphash()

           See "Functions that return an internal key should be treated as read only".

       •   EVP_PKEY_meth_*()

           See "Providers are a replacement for engines and low-level method overrides".

       •   EVP_PKEY_new_CMAC_key()

           See "Deprecated low-level MAC functions".

       •   EVP_PKEY_assign(),   EVP_PKEY_set1_DH(),   EVP_PKEY_set1_DSA(),   EVP_PKEY_set1_EC_KEY(),
           EVP_PKEY_set1_RSA()

           See "Deprecated low-level key object getters and setters"

       •   EVP_PKEY_set1_tls_encodedpoint() EVP_PKEY_get1_tls_encodedpoint()

           These functions were previously used by libssl to  set  or  get  an  encoded  public  key
           into/from  an  EVP_PKEY  object.  With OpenSSL 3.0 these are replaced by the more generic
           functions  EVP_PKEY_set1_encoded_public_key(3)  and  EVP_PKEY_get1_encoded_public_key(3).
           The  old  versions  have  been  converted  to  deprecated  macros  that just call the new
           functions.

       •   EVP_PKEY_set1_engine(), EVP_PKEY_get0_engine()

           See "Providers are a replacement for engines and low-level method overrides".

       •   EVP_PKEY_set_alias_type()

           This function has been removed. There is no replacement.  See  "EVP_PKEY_set_alias_type()
           method has been removed"

       •   HMAC_Init_ex(), HMAC_Update(), HMAC_Final(), HMAC_size()

           See "Deprecated low-level MAC functions".

       •   HMAC_CTX_new(), HMAC_CTX_free(), HMAC_CTX_copy(), HMAC_CTX_reset(), HMAC_CTX_set_flags(),
           HMAC_CTX_get_md()

           See "Deprecated low-level MAC functions".

       •   i2d_DHparams(), i2d_DHxparams()

           See  "Deprecated  low-level  key  reading  and  writing  functions"  and  "Migration"  in
           d2i_RSAPrivateKey(3)

       •   i2d_DSAparams(),  i2d_DSAPrivateKey(),  i2d_DSAPrivateKey_bio(),  i2d_DSAPrivateKey_fp(),
           i2d_DSA_PUBKEY(), i2d_DSA_PUBKEY_bio(), i2d_DSA_PUBKEY_fp(), i2d_DSAPublicKey()

           See  "Deprecated  low-level  key  reading  and  writing  functions"  and  "Migration"  in
           d2i_RSAPrivateKey(3)

       •   i2d_ECParameters(),  i2d_ECPrivateKey(),  i2d_ECPrivateKey_bio(),  i2d_ECPrivateKey_fp(),
           i2d_EC_PUBKEY(), i2d_EC_PUBKEY_bio(), i2d_EC_PUBKEY_fp(), i2o_ECPublicKey()

           See  "Deprecated  low-level  key  reading  and  writing  functions"  and  "Migration"  in
           d2i_RSAPrivateKey(3)

       •   i2d_RSAPrivateKey(), i2d_RSAPrivateKey_bio(),  i2d_RSAPrivateKey_fp(),  i2d_RSA_PUBKEY(),
           i2d_RSA_PUBKEY_bio(),  i2d_RSA_PUBKEY_fp(),  i2d_RSAPublicKey(),  i2d_RSAPublicKey_bio(),
           i2d_RSAPublicKey_fp()

           See  "Deprecated  low-level  key  reading  and  writing  functions"  and  "Migration"  in
           d2i_RSAPrivateKey(3)

       •   IDEA_encrypt(),   IDEA_set_decrypt_key(),   IDEA_set_encrypt_key(),   IDEA_cbc_encrypt(),
           IDEA_cfb64_encrypt(), IDEA_ecb_encrypt(), IDEA_ofb64_encrypt()

           See "Deprecated low-level encryption functions".  IDEA  has  been  moved  to  the  Legacy
           Provider.

       •   IDEA_options()

           There is no replacement. This function returned a constant string.

       •   MD2(), MD2_Init(), MD2_Update(), MD2_Final()

           See  "Deprecated  low-level  encryption  functions".   MD2  has  been moved to the Legacy
           Provider.

       •   MD2_options()

           There is no replacement. This function returned a constant string.

       •   MD4(), MD4_Init(), MD4_Update(), MD4_Final(), MD4_Transform()

           See "Deprecated low-level encryption functions".   MD4  has  been  moved  to  the  Legacy
           Provider.

       •   MDC2(), MDC2_Init(), MDC2_Update(), MDC2_Final()

           See  "Deprecated  low-level  encryption  functions".   MDC2  has been moved to the Legacy
           Provider.

       •   MD5(), MD5_Init(), MD5_Update(), MD5_Final(), MD5_Transform()

           See "Deprecated low-level encryption functions".

       •   NCONF_WIN32()

           This undocumented function has no replacement.   See  "HISTORY"  in  config(5)  for  more
           details.

       •   OCSP_parse_url()

           Use OSSL_HTTP_parse_url(3) instead.

       •   OCSP_REQ_CTX type and OCSP_REQ_CTX_*() functions

           These  methods  were  used  to  collect all necessary data to form a HTTP request, and to
           perform  the  HTTP  transfer  with  that  request.   With  OpenSSL  3.0,  the   type   is
           OSSL_HTTP_REQ_CTX,  and the deprecated functions are replaced with OSSL_HTTP_REQ_CTX_*().
           See OSSL_HTTP_REQ_CTX(3) for additional details.

       •   OPENSSL_fork_child(), OPENSSL_fork_parent(), OPENSSL_fork_prepare()

           There is no replacement for these functions. These  pthread  fork  support  methods  were
           unused by OpenSSL.

       •   OSSL_STORE_ctrl(),      OSSL_STORE_do_all_loaders(),     OSSL_STORE_LOADER_get0_engine(),
           OSSL_STORE_LOADER_get0_scheme(), OSSL_STORE_LOADER_new(), OSSL_STORE_LOADER_set_attach(),
           OSSL_STORE_LOADER_set_close(), OSSL_STORE_LOADER_set_ctrl(), OSSL_STORE_LOADER_set_eof(),
           OSSL_STORE_LOADER_set_error(),                            OSSL_STORE_LOADER_set_expect(),
           OSSL_STORE_LOADER_set_find(), OSSL_STORE_LOADER_set_load(), OSSL_STORE_LOADER_set_open(),
           OSSL_STORE_LOADER_set_open_ex(),                            OSSL_STORE_register_loader(),
           OSSL_STORE_unregister_loader(), OSSL_STORE_vctrl()

           These  functions  helped  applications  and  engines  create  loaders  for  schemes  they
           supported.    These   are   all   deprecated   and  discouraged  in  favour  of  provider
           implementations, see provider-storemgmt(7).

       •   PEM_read_DHparams(),            PEM_read_bio_DHparams(),            PEM_read_DSAparams(),
           PEM_read_bio_DSAparams(),         PEM_read_DSAPrivateKey(),        PEM_read_DSA_PUBKEY(),
           PEM_read_bio_DSAPrivateKey  and   PEM_read_bio_DSA_PUBKEY(),   PEM_read_ECPKParameters(),
           PEM_read_ECPrivateKey(),       PEM_read_EC_PUBKEY(),       PEM_read_bio_ECPKParameters(),
           PEM_read_bio_ECPrivateKey(),     PEM_read_bio_EC_PUBKEY(),      PEM_read_RSAPrivateKey(),
           PEM_read_RSA_PUBKEY(),       PEM_read_RSAPublicKey(),       PEM_read_bio_RSAPrivateKey(),
           PEM_read_bio_RSA_PUBKEY(),     PEM_read_bio_RSAPublicKey(),     PEM_write_bio_DHparams(),
           PEM_write_bio_DHxparams(),          PEM_write_DHparams(),          PEM_write_DHxparams(),
           PEM_write_DSAparams(),         PEM_write_DSAPrivateKey(),         PEM_write_DSA_PUBKEY(),
           PEM_write_bio_DSAparams(),   PEM_write_bio_DSAPrivateKey(),   PEM_write_bio_DSA_PUBKEY(),
           PEM_write_ECPKParameters(),       PEM_write_ECPrivateKey(),        PEM_write_EC_PUBKEY(),
           PEM_write_bio_ECPKParameters(),  PEM_write_bio_ECPrivateKey(), PEM_write_bio_EC_PUBKEY(),
           PEM_write_RSAPrivateKey(),       PEM_write_RSA_PUBKEY(),        PEM_write_RSAPublicKey(),
           PEM_write_bio_RSAPrivateKey(), PEM_write_bio_RSA_PUBKEY(), PEM_write_bio_RSAPublicKey(),

           See "Deprecated low-level key reading and writing functions"

       •   PKCS1_MGF1()

           See "Deprecated low-level encryption functions".

       •   RAND_get_rand_method(), RAND_set_rand_method(), RAND_OpenSSL(), RAND_set_rand_engine()

           Applications  should instead use RAND_set_DRBG_type(3), EVP_RAND(3) and EVP_RAND(7).  See
           RAND_set_rand_method(3) for more details.

       •   RC2_encrypt(),  RC2_decrypt(),  RC2_set_key(),  RC2_cbc_encrypt(),   RC2_cfb64_encrypt(),
           RC2_ecb_encrypt(),     RC2_ofb64_encrypt(),    RC4(),    RC4_set_key(),    RC4_options(),
           RC5_32_encrypt(),     RC5_32_set_key(),      RC5_32_decrypt(),      RC5_32_cbc_encrypt(),
           RC5_32_cfb64_encrypt(), RC5_32_ecb_encrypt(), RC5_32_ofb64_encrypt()

           See  "Deprecated  low-level encryption functions".  The Algorithms "RC2", "RC4" and "RC5"
           have been moved to the Legacy Provider.

       •   RIPEMD160(),       RIPEMD160_Init(),        RIPEMD160_Update(),        RIPEMD160_Final(),
           RIPEMD160_Transform()

           See  "Deprecated  low-level  digest functions".  The RIPE algorithm has been moved to the
           Legacy Provider.

       •   RSA_bits(), RSA_security_bits(), RSA_size()

           Use EVP_PKEY_get_bits(3), EVP_PKEY_get_security_bits(3) and EVP_PKEY_get_size(3).

       •   RSA_check_key(), RSA_check_key_ex()

           See "Deprecated low-level validation functions"

       •   RSA_clear_flags(), RSA_flags(), RSA_set_flags(), RSA_test_flags(),  RSA_setup_blinding(),
           RSA_blinding_off(), RSA_blinding_on()

           All of these RSA flags have been deprecated without replacement:

           RSA_FLAG_BLINDING,   RSA_FLAG_CACHE_PRIVATE,   RSA_FLAG_CACHE_PUBLIC,  RSA_FLAG_EXT_PKEY,
           RSA_FLAG_NO_BLINDING, RSA_FLAG_THREAD_SAFE RSA_METHOD_FLAG_NO_CHECK

       •   RSA_generate_key_ex(), RSA_generate_multi_prime_key()

           See "Deprecated low-level key generation functions".

       •   RSA_get0_engine()

           See "Providers are a replacement for engines and low-level method overrides"

       •   RSA_get0_crt_params(),  RSA_get0_d(),  RSA_get0_dmp1(),  RSA_get0_dmq1(),   RSA_get0_e(),
           RSA_get0_factors(),  RSA_get0_iqmp(),  RSA_get0_key(), RSA_get0_multi_prime_crt_params(),
           RSA_get0_multi_prime_factors(),   RSA_get0_n(),   RSA_get0_p(),    RSA_get0_pss_params(),
           RSA_get0_q(), RSA_get_multi_prime_extra_count()

           See "Deprecated low-level key parameter getters"

       •   RSA_new(), RSA_free(), RSA_up_ref()

           See "Deprecated low-level object creation".

       •   RSA_get_default_method(), RSA_get_ex_data and RSA_get_method()

           See "Providers are a replacement for engines and low-level method overrides".

       •   RSA_get_version()

           There is no replacement.

       •   RSA_meth_*(), RSA_new_method(), RSA_null_method and RSA_PKCS1_OpenSSL()

           See "Providers are a replacement for engines and low-level method overrides".

       •   RSA_padding_add_*(), RSA_padding_check_*()

           See  "Deprecated  low-level  signing  functions"  and  "Deprecated  low-level  encryption
           functions".

       •   RSA_print(), RSA_print_fp()

           See "Deprecated low-level key printing functions"

       •   RSA_public_encrypt(), RSA_private_decrypt()

           See "Deprecated low-level encryption functions"

       •   RSA_private_encrypt(), RSA_public_decrypt()

           This is equivalent to doing sign and verify recover operations (with a  padding  mode  of
           none). See "Deprecated low-level signing functions".

       •   RSAPrivateKey_dup(), RSAPublicKey_dup()

           There is no direct replacement. Applications may use EVP_PKEY_dup(3).

       •   RSAPublicKey_it(), RSAPrivateKey_it()

           See "Deprecated low-level key reading and writing functions"

       •   RSA_set0_crt_params(), RSA_set0_factors(), RSA_set0_key(), RSA_set0_multi_prime_params()

           See "Deprecated low-level key parameter setters".

       •   RSA_set_default_method(), RSA_set_method(), RSA_set_ex_data()

           See "Providers are a replacement for engines and low-level method overrides"

       •   RSA_sign(),  RSA_sign_ASN1_OCTET_STRING(),  RSA_verify(), RSA_verify_ASN1_OCTET_STRING(),
           RSA_verify_PKCS1_PSS(), RSA_verify_PKCS1_PSS_mgf1()

           See "Deprecated low-level signing functions".

       •   RSA_X931_derive_ex(), RSA_X931_generate_key_ex(), RSA_X931_hash_id()

           There are no replacements for these functions.  X931 padding can be set using  "Signature
           Parameters" in EVP_SIGNATURE-RSA(7).  See OSSL_SIGNATURE_PARAM_PAD_MODE.

       •   SEED_encrypt(),         SEED_decrypt(),        SEED_set_key(),        SEED_cbc_encrypt(),
           SEED_cfb128_encrypt(), SEED_ecb_encrypt(), SEED_ofb128_encrypt()

           See "Deprecated low-level encryption functions".  The SEED algorithm has  been  moved  to
           the Legacy Provider.

       •   SHA1_Init(),     SHA1_Update(),     SHA1_Final(),     SHA1_Transform(),    SHA224_Init(),
           SHA224_Update(),   SHA224_Final(),   SHA256_Init(),   SHA256_Update(),    SHA256_Final(),
           SHA256_Transform(),   SHA384_Init(),   SHA384_Update(),   SHA384_Final(),  SHA512_Init(),
           SHA512_Update(), SHA512_Final(), SHA512_Transform()

           See "Deprecated low-level digest functions".

       •   SRP_Calc_A(), SRP_Calc_B(), SRP_Calc_client_key(),  SRP_Calc_server_key(),  SRP_Calc_u(),
           SRP_Calc_x(),              SRP_check_known_gN_param(),             SRP_create_verifier(),
           SRP_create_verifier_BN(), SRP_get_default_gN(), SRP_user_pwd_free(),  SRP_user_pwd_new(),
           SRP_user_pwd_set0_sv(),          SRP_user_pwd_set1_ids(),          SRP_user_pwd_set_gN(),
           SRP_VBASE_add0_user(),  SRP_VBASE_free(),   SRP_VBASE_get1_by_user(),   SRP_VBASE_init(),
           SRP_VBASE_new(), SRP_Verify_A_mod_N(), SRP_Verify_B_mod_N()

           There are no replacements for the SRP functions.

       •   SSL_CTX_set_tmp_dh_callback(),      SSL_set_tmp_dh_callback(),      SSL_CTX_set_tmp_dh(),
           SSL_set_tmp_dh()

           These are used to set the Diffie-Hellman (DH) parameters that are to be used  by  servers
           requiring  ephemeral  DH keys. Instead applications should consider using the built-in DH
           parameters that are available by calling SSL_CTX_set_dh_auto(3) or SSL_set_dh_auto(3). If
           custom parameters are necessary then  applications  can  use  the  alternative  functions
           SSL_CTX_set0_tmp_dh_pkey(3)  and  SSL_set0_tmp_dh_pkey(3). There is no direct replacement
           for the "callback" functions. The  callback  was  originally  useful  in  order  to  have
           different  parameters  for export and non-export ciphersuites. Export ciphersuites are no
           longer supported by OpenSSL. Use of the callback functions should be replaced by  one  of
           the other methods described above.

       •   SSL_CTX_set_tlsext_ticket_key_cb()

           Use the new SSL_CTX_set_tlsext_ticket_key_evp_cb(3) function instead.

       •   WHIRLPOOL(),        WHIRLPOOL_Init(),        WHIRLPOOL_Update(),       WHIRLPOOL_Final(),
           WHIRLPOOL_BitUpdate()

           See "Deprecated low-level digest functions".  The Whirlpool algorithm has been  moved  to
           the Legacy Provider.

       •   X509_certificate_type()

           This   was  an  undocumented  function.  Applications  can  use  X509_get0_pubkey(3)  and
           X509_get0_signature(3) instead.

       •   X509_http_nbio(), X509_CRL_http_nbio()

           Use X509_load_http(3) and X509_CRL_load_http(3) instead.

       NID handling for provided keys and algorithms

       The following functions for NID (numeric id) handling have changed semantics.

       •   EVP_PKEY_id(), EVP_PKEY_get_id()

           This function was previously used to reliably return the NID of an EVP_PKEY object, e.g.,
           to look up the name of the algorithm of such EVP_PKEY by calling OBJ_nid2sn(3). With  the
           introduction of provider(7)s EVP_PKEY_id() or its new equivalent EVP_PKEY_get_id(3) might
           now  also  return  the  value  -1  (EVP_PKEY_KEYMGMT) indicating the use of a provider to
           implement the EVP_PKEY  object.  Therefore,  the  use  of  EVP_PKEY_get0_type_name(3)  is
           recommended for retrieving the name of the EVP_PKEY algorithm.

   Using the FIPS Module in applications
       See fips_module(7) and OSSL_PROVIDER-FIPS(7) for details.

   OpenSSL command line application changes
       New applications

       openssl kdf uses the new EVP_KDF(3) API.  openssl kdf uses the new EVP_MAC(3) API.

       Added options

       -provider_path and -provider are available to all apps and can be used multiple times to load
       any  providers,  such  as  the  'legacy'  provider or third party providers. If used then the
       'default' provider would also need to be specified if required. The  -provider_path  must  be
       specified before the -provider option.

       The list app has many new options. See openssl-list(1) for more information.

       -crl_lastupdate  and  -crl_nextupdate used by openssl ca allows explicit setting of fields in
       the generated CRL.

       Removed options

       Interactive mode is not longer available.

       The -crypt option used by openssl passwd.  The  -c  option  used  by  openssl  x509,  openssl
       dhparam, openssl dsaparam, and openssl ecparam.

       Other Changes

       The  output of Command line applications may have minor changes.  These are primarily changes
       in capitalisation and white space.  However, in some cases, there are additional differences.
       For example, the DH parameters output from openssl  dhparam  now  lists  'P',  'Q',  'G'  and
       'pcounter' instead of 'prime', 'generator', 'subgroup order' and 'counter' respectively.

       The  openssl commands that read keys, certificates, and CRLs now automatically detect the PEM
       or DER format of the input files so it is not  necessary  to  explicitly  specify  the  input
       format  anymore.  However  if  the  input  format option is used the specified format will be
       required.

       openssl speed no longer uses low-level API calls.   This  implies  some  of  the  performance
       numbers  might  not  be  comparable  with  the previous releases due to higher overhead. This
       applies particularly to measuring performance on smaller data chunks.

       b<openssl dhparam>, openssl dsa, openssl gendsa, openssl dsaparam, openssl genrsa and openssl
       rsa have been modified to use PKEY APIs.  openssl genrsa and openssl rsa now  write  PKCS  #8
       keys by default.

       Default settings

       "SHA256" is now the default digest for TS query used by openssl ts.

       Deprecated apps

       openssl  rsautl  is  deprecated,  use openssl pkeyutl instead.  openssl dhparam, openssl dsa,
       openssl gendsa, openssl dsaparam, openssl genrsa, openssl rsa, openssl genrsa and openssl rsa
       are now in maintenance mode and no new features will be added to them.

   TLS Changes
       •   TLS 1.3 FFDHE key exchange support added

           This uses DH safe prime named groups.

       •   Support for fully "pluggable" TLSv1.3 groups.

           This means that providers may supply their own group implementations  (using  either  the
           "key  exchange"  or the "key encapsulation" methods) which will automatically be detected
           and used by libssl.

       •   SSL and SSL_CTX options are now 64 bit instead of 32 bit.

           The signatures of the functions to get and set options on SSL and SSL_CTX objects changed
           from "unsigned long" to "uint64_t" type.

           This may require source code changes. For example it is no longer  possible  to  use  the
           SSL_OP_  macro  values in preprocessor "#if" conditions.  However it is still possible to
           test whether these macros are defined or not.

           See    SSL_CTX_get_options(3),     SSL_CTX_set_options(3),     SSL_get_options(3)     and
           SSL_set_options(3).

       •   SSL_set1_host() and SSL_add1_host() Changes

           These functions now take IP literal addresses as well as actual hostnames.

       •   Added SSL option SSL_OP_CLEANSE_PLAINTEXT

           If  the  option is set, openssl cleanses (zeroizes) plaintext bytes from internal buffers
           after delivering them to the application. Note, the application is still responsible  for
           cleansing other copies (e.g.: data received by SSL_read(3)).

       •   Client-initiated renegotiation is disabled by default.

           To  allow it, use the -client_renegotiation option, the SSL_OP_ALLOW_CLIENT_RENEGOTIATION
           flag, or the "ClientRenegotiation" config parameter as appropriate.

       •   Secure renegotiation is now required by default for TLS connections

           Support for RFC 5746 secure renegotiation is now required  by  default  for  SSL  or  TLS
           connections to succeed.  Applications that require the ability to connect to legacy peers
           will    need    to    explicitly    set    SSL_OP_LEGACY_SERVER_CONNECT.     Accordingly,
           SSL_OP_LEGACY_SERVER_CONNECT is no longer set as part of SSL_OP_ALL.

       •   Combining the Configure options no-ec and no-dh no longer disables TLSv1.3

           Typically if OpenSSL has no EC or DH algorithms then it cannot support  connections  with
           TLSv1.3.  However  OpenSSL  now  supports "pluggable" groups through providers. Therefore
           third party providers may supply group implementations even where there are  no  built-in
           ones. Attempting to create TLS connections in such a build without also disabling TLSv1.3
           at  run  time  or  using  third  party  provider groups may result in handshake failures.
           TLSv1.3 can be disabled at compile time using the "no-tls1_3" Configure option.

       •   SSL_CTX_set_ciphersuites() and SSL_set_ciphersuites() changes.

           The methods now ignore unknown ciphers.

       •   Security callback change.

           The security callback, which can be customised by application code, supports the security
           operation SSL_SECOP_TMP_DH. This is defined to take an EVP_PKEY in the "other" parameter.
           In most places this is what is passed. All these places occur server side. However  there
           was  one  client  side call of this security operation and it passed a DH object instead.
           This is incorrect according to the definition of SSL_SECOP_TMP_DH,  and  is  inconsistent
           with all of the other locations. Therefore this client side call has been changed to pass
           an EVP_PKEY instead.

       •   New SSL option SSL_OP_IGNORE_UNEXPECTED_EOF

           The  SSL  option  SSL_OP_IGNORE_UNEXPECTED_EOF  is  introduced. If that option is set, an
           unexpected EOF is ignored, it pretends a close notify was received  instead  and  so  the
           returned error becomes SSL_ERROR_ZERO_RETURN.

       •   The security strength of SHA1 and MD5 based signatures in TLS has been reduced.

           This  results  in  SSL  3, TLS 1.0, TLS 1.1 and DTLS 1.0 no longer working at the default
           security level of 1 and instead requires security level 0.  The  security  level  can  be
           changed    either    using    the    cipher    string    with   @SECLEVEL,   or   calling
           SSL_CTX_set_security_level(3). This  also  means  that  where  the  signature  algorithms
           extension  is  missing  from  a  ClientHello  then  the handshake will fail in TLS 1.2 at
           security level 1. This is because,  although  this  extension  is  optional,  failing  to
           provide  one  means  that OpenSSL will fallback to a default set of signature algorithms.
           This default set requires the availability of SHA1.

       •   X509 certificates signed using SHA1 are no longer allowed at security level 1 and above.

           In TLS/SSL the default security level is 1. It can be set either using the cipher  string
           with  @SECLEVEL,  or  calling  SSL_CTX_set_security_level(3).  If the leaf certificate is
           signed with SHA-1, a call to SSL_CTX_use_certificate(3) will fail if the  security  level
           is not lowered first.  Outside TLS/SSL, the default security level is -1 (effectively 0).
           It  can be set using X509_VERIFY_PARAM_set_auth_level(3) or using the -auth_level options
           of the commands.

SEE ALSO
       fips_module(7)

HISTORY
       The migration guide was created for OpenSSL 3.0.

COPYRIGHT
       Copyright 2021-2023 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file  except  in
       compliance  with  the  License.   You  can  obtain  a  copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.

3.0.13                                       2026-07-29                        MIGRATION_GUIDE(7SSL)
migration_guide(7ssl) □✕
NAME SYNOPSIS DESCRIPTION SEE ALSO HISTORY COPYRIGHT

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