man > openssl-cms(1)

Che Dong

OPENSSL-CMS(1SSL) OpenSSL OPENSSL-CMS(1SSL)

NAME
openssl-cms - CMS command

SYNOPSIS
openssl cms [-help]

General options:

[-in filename] [-out filename] [-config configfile]

Operation options:

[-encrypt] [-decrypt] [-sign] [-verify] [-resign] [-sign_receipt] [-verify_receipt receipt]
[-digest_create] [-digest_verify] [-compress] [-uncompress] [-EncryptedData_encrypt]
[-EncryptedData_decrypt] [-data_create] [-data_out] [-cmsout]

File format options:

[-inform DER|PEM|SMIME] [-outform DER|PEM|SMIME] [-rctform DER|PEM|SMIME] [-stream] [-indef]
[-noindef] [-binary] [-crlfeol] [-asciicrlf]

Keys and password options:

[-pwri_password password] [-secretkey key] [-secretkeyid id] [-inkey filename|uri] [-passin
arg] [-keyopt name:parameter] [-keyform DER|PEM|P12|ENGINE] [-engine id] [-provider name]
[-provider-path path] [-propquery propq] [-rand files] [-writerand file]

Encryption options:

[-originator file] [-recip file] [recipient-cert ...] [-cipher] [-wrap cipher]
[-aes128-wrap] [-aes192-wrap] [-aes256-wrap] [-des3-wrap] [-debug_decrypt]

Signing options:

[-md digest] [-signer file] [-certfile file] [-cades] [-nodetach] [-nocerts] [-noattr]
[-nosmimecap] [-receipt_request_all] [-receipt_request_first] [-receipt_request_from
emailaddress] [-receipt_request_to emailaddress]

Verification options:

[-signer file] [-content filename] [-no_content_verify] [-no_attr_verify] [-nosigs]
[-noverify] [-nointern] [-cades] [-verify_retcode] [-CAfile file] [-no-CAfile] [-CApath dir]
[-no-CApath] [-CAstore uri] [-no-CAstore]

Output options:

[-keyid] [-econtent_type type] [-text] [-certsout file] [-to addr] [-from addr] [-subject
subj]

Printing options:

[-noout] [-print] [-nameopt option] [-receipt_request_print]

Validation options:

[-allow_proxy_certs] [-attime timestamp] [-no_check_time] [-check_ss_sig] [-crl_check]
[-crl_check_all] [-explicit_policy] [-extended_crl] [-ignore_critical] [-inhibit_any]
[-inhibit_map] [-partial_chain] [-policy arg] [-policy_check] [-policy_print] [-purpose
purpose] [-suiteB_128] [-suiteB_128_only] [-suiteB_192] [-trusted_first] [-no_alt_chains]
[-use_deltas] [-auth_level num] [-verify_depth num] [-verify_email email] [-verify_hostname
hostname] [-verify_ip ip] [-verify_name name] [-x509_strict] [-issuer_checks]

DESCRIPTION
This command handles data in CMS format such as S/MIME v3.1 email messages. It can encrypt,
decrypt, sign, verify, compress, uncompress, and print messages.

OPTIONS
There are a number of operation options that set the type of operation to be performed:
encrypt, decrypt, sign, verify, resign, sign_receipt, verify_receipt, digest_create,
digest_verify, compress, uncompress, EncryptedData_encrypt, EncryptedData_decrypt,
data_create, data_out, or cmsout. The relevance of the other options depends on the
operation type and their meaning may vary according to it.

-help
Print out a usage message.

General options
-in filename
The input message to be encrypted or signed or the message to be decrypted or verified.

-out filename
The message text that has been decrypted or verified or the output MIME format message
that has been signed or verified.

-config configfile
See "Configuration Option" in openssl(1).

Operation options
-encrypt
Encrypt data for the given recipient certificates. Input file is the message to be
encrypted. The output file is the encrypted data in MIME format. The actual CMS type is
EnvelopedData.

Note that no revocation check is done for the recipient cert, so if that key has been
compromised, others may be able to decrypt the text.

-decrypt
Decrypt data using the supplied certificate and private key. Expects encrypted datain
MIME format for the input file. The decrypted data is written to the output file.

-sign
Sign data using the supplied certificate and private key. Input file is the message to be
signed. The signed data in MIME format is written to the output file.

-verify
Verify signed data. Expects a signed data on input and outputs the signed data. Both
clear text and opaque signing is supported.

-resign
Resign a message: take an existing message and one or more new signers.

-sign_receipt
Generate and output a signed receipt for the supplied message. The input message must
contain a signed receipt request. Functionality is otherwise similar to the -sign
operation.

-verify_receipt receipt
Verify a signed receipt in filename receipt. The input message must contain the original
receipt request. Functionality is otherwise similar to the -verify operation.

-digest_create
Create a CMS DigestedData type.

-digest_verify
Verify a CMS DigestedData type and output the content.

-compress
Create a CMS CompressedData type. OpenSSL must be compiled with zlib support for this
option to work, otherwise it will output an error.

-uncompress
Uncompress a CMS CompressedData type and output the content. OpenSSL must be compiled
with zlib support for this option to work, otherwise it will output an error.

-EncryptedData_encrypt
Encrypt content using supplied symmetric key and algorithm using a CMS EncryptedData type
and output the content.

-EncryptedData_decrypt
Decrypt content using supplied symmetric key and algorithm using a CMS EncryptedData type
and output the content.

-data_create
Create a CMS Data type.

-data_out
Data type and output the content.

-cmsout
Takes an input message and writes out a PEM encoded CMS structure.

File format options
-inform DER|PEM|SMIME
The input format of the CMS structure (if one is being read); the default is SMIME. See
openssl-format-options(1) for details.

-outform DER|PEM|SMIME
The output format of the CMS structure (if one is being written); the default is SMIME.
See openssl-format-options(1) for details.

-rctform DER|PEM|SMIME
The signed receipt format for use with the -receipt_verify; the default is SMIME. See
openssl-format-options(1) for details.

-stream, -indef
The -stream and -indef options are equivalent and enable streaming I/O for encoding
operations. This permits single pass processing of data without the need to hold the
entire contents in memory, potentially supporting very large files. Streaming is
automatically set for S/MIME signing with detached data if the output format is SMIME it
is currently off by default for all other operations.

-noindef
Disable streaming I/O where it would produce and indefinite length constructed encoding.
This option currently has no effect. In future streaming will be enabled by default on
all relevant operations and this option will disable it.

-binary
Normally the input message is converted to "canonical" format which is effectively using
CR and LF as end of line: as required by the S/MIME specification. When this option is
present no translation occurs. This is useful when handling binary data which may not be
in MIME format.

-crlfeol
Normally the output file uses a single LF as end of line. When this option is present
CRLF is used instead.

-asciicrlf
When signing use ASCII CRLF format canonicalisation. This strips trailing whitespace from
all lines, deletes trailing blank lines at EOF and sets the encapsulated content type.
This option is normally used with detached content and an output signature format of DER.
This option is not normally needed when verifying as it is enabled automatically if the
encapsulated content format is detected.

Keys and password options
-pwri_password password
Specify password for recipient.

-secretkey key
Specify symmetric key to use. The key must be supplied in hex format and be consistent
with the algorithm used. Supported by the -EncryptedData_encrypt -EncryptedData_decrypt,
-encrypt and -decrypt options. When used with -encrypt or -decrypt the supplied key is
used to wrap or unwrap the content encryption key using an AES key in the
KEKRecipientInfo type.

-secretkeyid id
The key identifier for the supplied symmetric key for KEKRecipientInfo type. This option
must be present if the -secretkey option is used with -encrypt. With -decrypt operations
the id is used to locate the relevant key if it is not supplied then an attempt is used
to decrypt any KEKRecipientInfo structures.

-inkey filename|uri
The private key to use when signing or decrypting. This must match the corresponding
certificate. If this option is not specified then the private key must be included in the
certificate file specified with the -recip or -signer file. When signing this option can
be used multiple times to specify successive keys.

-passin arg
The private key password source. For more information about the format of arg see
openssl-passphrase-options(1).

-keyopt name:parameter
For signing and encryption this option can be used multiple times to set customised
parameters for the preceding key or certificate. It can currently be used to set RSA-PSS
for signing, RSA-OAEP for encryption or to modify default parameters for ECDH.

-keyform DER|PEM|P12|ENGINE
The format of the private key file; unspecified by default. See
openssl-format-options(1) for details.

-engine id
See "Engine Options" in openssl(1). This option is deprecated.

-provider name
-provider-path path
-propquery propq
See "Provider Options" in openssl(1), provider(7), and property(7).

-rand files, -writerand file
See "Random State Options" in openssl(1) for details.

Encryption and decryption options
-originator file
A certificate of the originator of the encrypted message. Necessary for decryption when
Key Agreement is in use for a shared key.

-recip file
When decrypting a message this specifies the certificate of the recipient. The
certificate must match one of the recipients of the message.

When encrypting a message this option may be used multiple times to specify each
recipient. This form must be used if customised parameters are required (for example to
specify RSA-OAEP).

Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this option.

recipient-cert ...
This is an alternative to using the -recip option when encrypting a message. One or more
certificate filenames may be given.

-[4mcipher
The encryption algorithm to use. For example triple DES (168 bits) - -des3 or 256 bit AES
- -aes256. Any standard algorithm name (as used by the EVP_get_cipherbyname() function)
can also be used preceded by a dash, for example -aes-128-cbc. See openssl-enc(1) for a
list of ciphers supported by your version of OpenSSL.

Currently the AES variants with GCM mode are the only supported AEAD algorithms.

If not specified triple DES is used. Only used with -encrypt and -EncryptedData_create
commands.

-wrap cipher
Cipher algorithm to use for key wrap when encrypting the message using Key Agreement for
key transport. The algorithm specified should be suitable for key wrap.

-aes128-wrap, -aes192-wrap, -aes256-wrap, -des3-wrap
Use AES128, AES192, AES256, or 3DES-EDE, respectively, to wrap key. Depending on the
OpenSSL build options used, -des3-wrap may not be supported.

-debug_decrypt
This option sets the CMS_DEBUG_DECRYPT flag. This option should be used with caution: see
the notes section below.

Signing options
-md digest
Digest algorithm to use when signing or resigning. If not present then the default digest
algorithm for the signing key will be used (usually SHA1).

-signer file
A signing certificate. When signing or resigning a message, this option can be used
multiple times if more than one signer is required.

-certfile file
Allows additional certificates to be specified. When signing these will be included with
the message. When verifying these will be searched for the signers certificates. The
input can be in PEM, DER, or PKCS#12 format.

-cades
When used with -sign, add an ESS signingCertificate or ESS signingCertificateV2 signed-
attribute to the SignerInfo, in order to make the signature comply with the requirements
for a CAdES Basic Electronic Signature (CAdES-BES).

-nodetach
When signing a message use opaque signing: this form is more resistant to translation by
mail relays but it cannot be read by mail agents that do not support S/MIME. Without
this option cleartext signing with the MIME type multipart/signed is used.

-nocerts
When signing a message the signer's certificate is normally included with this option it
is excluded. This will reduce the size of the signed message but the verifier must have a
copy of the signers certificate available locally (passed using the -certfile option for
example).

-noattr
Normally when a message is signed a set of attributes are included which include the
signing time and supported symmetric algorithms. With this option they are not included.

-nosmimecap
Exclude the list of supported algorithms from signed attributes, other options such as
signing time and content type are still included.

-receipt_request_all, -receipt_request_first
For -sign option include a signed receipt request. Indicate requests should be provided
by all recipient or first tier recipients (those mailed directly and not from a mailing
list). Ignored it -receipt_request_from is included.

-receipt_request_from emailaddress
For -sign option include a signed receipt request. Add an explicit email address where
receipts should be supplied.

-receipt_request_to emailaddress
Add an explicit email address where signed receipts should be sent to. This option must
but supplied if a signed receipt is requested.

Verification options
-signer file
If a message has been verified successfully then the signers certificate(s) will be
written to this file if the verification was successful.

-content filename
This specifies a file containing the detached content for operations taking S/MIME input,
such as the -verify command. This is only usable if the CMS structure is using the
detached signature form where the content is not included. This option will override any
content if the input format is S/MIME and it uses the multipart/signed MIME content type.

-no_content_verify
Do not verify signed content signatures.

-no_attr_verify
Do not verify signed attribute signatures.

-nosigs
Don't verify message signature.

-noverify
Do not verify the signers certificate of a signed message.

-nointern
When verifying a message normally certificates (if any) included in the message are
searched for the signing certificate. With this option only the certificates specified in
the -certfile option are used. The supplied certificates can still be used as untrusted
CAs however.

-cades
When used with -verify, require and check signer certificate digest. See the NOTES
section for more details.

-verify_retcode
Exit nonzero on verification failure.

-CAfile file, -no-CAfile, -CApath dir, -no-CApath, -CAstore uri, -no-CAstore
See "Trusted Certificate Options" in openssl-verification-options(1) for details.

Output options
-keyid
Use subject key identifier to identify certificates instead of issuer name and serial
number. The supplied certificate must include a subject key identifier extension.
Supported by -sign and -encrypt options.

-econtent_type type
Set the encapsulated content type to type if not supplied the Data type is used. The type
argument can be any valid OID name in either text or numerical format.

-text
This option adds plain text (text/plain) MIME headers to the supplied message if
encrypting or signing. If decrypting or verifying it strips off text headers: if the
decrypted or verified message is not of MIME type text/plain then an error occurs.

-certsout file
Any certificates contained in the input message are written to file.

-to, -from, -subject
The relevant email headers. These are included outside the signed portion of a message so
they may be included manually. If signing then many S/MIME mail clients check the signers
certificate's email address matches that specified in the From: address.

Printing options
-noout
For the -cmsout operation do not output the parsed CMS structure. This is useful if the
syntax of the CMS structure is being checked.

-print
For the -cmsout operation print out all fields of the CMS structure. This implies
-noout. This is mainly useful for testing purposes.

-nameopt option
For the -cmsout operation when -print option is in use, specifies printing options for
string fields. For most cases utf8 is reasonable value. See
openssl-namedisplay-options(1) for details.

-receipt_request_print
For the -verify operation print out the contents of any signed receipt requests.

Validation options
-allow_proxy_certs, -attime, -no_check_time, -check_ss_sig, -crl_check, -crl_check_all,
-explicit_policy, -extended_crl, -ignore_critical, -inhibit_any, -inhibit_map,
-no_alt_chains, -partial_chain, -policy, -policy_check, -policy_print, -purpose, -suiteB_128,
-suiteB_128_only, -suiteB_192, -trusted_first, -use_deltas, -auth_level, -verify_depth,
-verify_email, -verify_hostname, -verify_ip, -verify_name, -x509_strict -issuer_checks
Set various options of certificate chain verification. See "Verification Options" in
openssl-verification-options(1) for details.

Any validation errors cause the command to exit.

NOTES
The MIME message must be sent without any blank lines between the headers and the output.
Some mail programs will automatically add a blank line. Piping the mail directly to sendmail
is one way to achieve the correct format.

The supplied message to be signed or encrypted must include the necessary MIME headers or
many S/MIME clients won't display it properly (if at all). You can use the -text option to
automatically add plain text headers.

A "signed and encrypted" message is one where a signed message is then encrypted. This can be
produced by encrypting an already signed message: see the examples section.

This version of the program only allows one signer per message but it will verify multiple
signers on received messages. Some S/MIME clients choke if a message contains multiple
signers. It is possible to sign messages "in parallel" by signing an already signed message.

The options -encrypt and -decrypt reflect common usage in S/MIME clients. Strictly speaking
these process CMS enveloped data: CMS encrypted data is used for other purposes.

The -resign option uses an existing message digest when adding a new signer. This means that
attributes must be present in at least one existing signer using the same message digest or
this operation will fail.

The -stream and -indef options enable streaming I/O support. As a result the encoding is BER
using indefinite length constructed encoding and no longer DER. Streaming is supported for
the -encrypt operation and the -sign operation if the content is not detached.

Streaming is always used for the -sign operation with detached data but since the content is
no longer part of the CMS structure the encoding remains DER.

If the -decrypt option is used without a recipient certificate then an attempt is made to
locate the recipient by trying each potential recipient in turn using the supplied private
key. To thwart the MMA attack (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all
recipients are tried whether they succeed or not and if no recipients match the message is
"decrypted" using a random key which will typically output garbage. The -debug_decrypt
option can be used to disable the MMA attack protection and return an error if no recipient
can be found: this option should be used with caution. For a fuller description see
CMS_decrypt(3)).

CADES BASIC ELECTRONIC SIGNATURE (CADES-BES)
A CAdES Basic Electronic Signature (CAdES-BES), as defined in the European Standard ETSI EN
319 122-1 V1.1.1, contains:

• The signed user data as defined in CMS (RFC 3852);

• Content-type of the EncapsulatedContentInfo value being signed;

• Message-digest of the eContent OCTET STRING within encapContentInfo being signed;

• An ESS signingCertificate or ESS signingCertificateV2 attribute, as defined in Enhanced
Security Services (ESS), RFC 2634 and RFC 5035. An ESS signingCertificate attribute only
allows for SHA-1 as digest algorithm. An ESS signingCertificateV2 attribute allows for
any digest algorithm.

• The digital signature value computed on the user data and, when present, on the signed
attributes.

NOTE that the -cades option applies to the -sign or -verify operations. With this
option, the -verify operation also requires that the signingCertificate attribute is
present and checks that the given identifiers match the verification trust chain built
during the verification process.

EXIT CODES
0 The operation was completely successfully.

1 An error occurred parsing the command options.

2 One of the input files could not be read.

3 An error occurred creating the CMS file or when reading the MIME message.

4 An error occurred decrypting or verifying the message.

5 The message was verified correctly but an error occurred writing out the signers
certificates.

COMPATIBILITY WITH PKCS#7 FORMAT
openssl-smime(1) can only process the older PKCS#7 format. openssl cms supports
Cryptographic Message Syntax format. Use of some features will result in messages which
cannot be processed by applications which only support the older format. These are detailed
below.

The use of the -keyid option with -sign or -encrypt.

The -outform PEM option uses different headers.

The -compress option.

The -secretkey option when used with -encrypt.

The use of PSS with -sign.

The use of OAEP or non-RSA keys with -encrypt.

Additionally the -EncryptedData_create and -data_create type cannot be processed by the older
openssl-smime(1) command.

EXAMPLES
Create a cleartext signed message:

openssl cms -sign -in message.txt -text -out mail.msg \
-signer mycert.pem

Create an opaque signed message

openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
-signer mycert.pem

Create a signed message, include some additional certificates and read the private key from
another file:

openssl cms -sign -in in.txt -text -out mail.msg \
-signer mycert.pem -inkey mykey.pem -certfile mycerts.pem

Create a signed message with two signers, use key identifier:

openssl cms -sign -in message.txt -text -out mail.msg \
-signer mycert.pem -signer othercert.pem -keyid

Send a signed message under Unix directly to sendmail, including headers:

openssl cms -sign -in in.txt -text -signer mycert.pem \
-from steve AT openssl.org -to someone@somewhere \
-subject "Signed message" | sendmail someone@somewhere

Verify a message and extract the signer's certificate if successful:

openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt

Send encrypted mail using triple DES:

openssl cms -encrypt -in in.txt -from steve AT openssl.org \
-to someone@somewhere -subject "Encrypted message" \
-des3 user.pem -out mail.msg

Sign and encrypt mail:

openssl cms -sign -in ml.txt -signer my.pem -text \
| openssl cms -encrypt -out mail.msg \
-from steve AT openssl.org -to someone@somewhere \
-subject "Signed and Encrypted message" -des3 user.pem

Note: the encryption command does not include the -text option because the message being
encrypted already has MIME headers.

Decrypt a message:

openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem

The output from Netscape form signing is a PKCS#7 structure with the detached signature
format. You can use this program to verify the signature by line wrapping the base64 encoded
structure and surrounding it with:

-----BEGIN PKCS7-----
-----END PKCS7-----

and using the command,

openssl cms -verify -inform PEM -in signature.pem -content content.txt

alternatively you can base64 decode the signature and use

openssl cms -verify -inform DER -in signature.der -content content.txt

Create an encrypted message using 128 bit Camellia:

openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem

Add a signer to an existing message:

openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg

Sign a message using RSA-PSS:

openssl cms -sign -in message.txt -text -out mail.msg \
-signer mycert.pem -keyopt rsa_padding_mode:pss

Create an encrypted message using RSA-OAEP:

openssl cms -encrypt -in plain.txt -out mail.msg \
-recip cert.pem -keyopt rsa_padding_mode:oaep

Use SHA256 KDF with an ECDH certificate:

openssl cms -encrypt -in plain.txt -out mail.msg \
-recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256

Print CMS signed binary data in human-readable form:

openssl cms -in signed.cms -binary -inform DER -cmsout -print

BUGS
The MIME parser isn't very clever: it seems to handle most messages that I've thrown at it
but it may choke on others.

The code currently will only write out the signer's certificate to a file: if the signer has
a separate encryption certificate this must be manually extracted. There should be some
heuristic that determines the correct encryption certificate.

Ideally a database should be maintained of a certificates for each email address.

The code doesn't currently take note of the permitted symmetric encryption algorithms as
supplied in the SMIMECapabilities signed attribute. this means the user has to manually
include the correct encryption algorithm. It should store the list of permitted ciphers in a
database and only use those.

No revocation checking is done on the signer's certificate.