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OPENSSL-X509(1SSL) OpenSSL OPENSSL-X509(1SSL)
NAME
openssl-x509 - Certificate display and signing command
SYNOPSIS
openssl x509 [-help] [-in filename|uri] [-passin arg] [-new] [-x509toreq] [-req]
[-copy_extensions arg] [-inform DER|PEM] [-vfyopt nm:v] [-key filename|uri] [-keyform
DER|PEM|P12|ENGINE] [-signkey filename|uri] [-out filename] [-outform DER|PEM] [-nocert]
[-noout] [-dateopt] [-text] [-certopt option] [-fingerprint] [-alias] [-serial]
[-startdate] [-enddate] [-dates] [-subject] [-issuer] [-nameopt option] [-email] [-hash]
[-subject_hash] [-subject_hash_old] [-issuer_hash] [-issuer_hash_old] [-ext extensions]
[-ocspid] [-ocsp_uri] [-purpose] [-pubkey] [-modulus] [-checkend num] [-checkhost host]
[-checkemail host] [-checkip ipaddr] [-set_serial n] [-next_serial] [-days arg]
[-preserve_dates] [-subj arg] [-force_pubkey filename] [-clrext] [-extfile filename]
[-extensions section] [-sigopt nm:v] [-badsig] [-digest] [-CA filename|uri] [-CAform
DER|PEM|P12] [-CAkey filename|uri] [-CAkeyform DER|PEM|P12|ENGINE] [-CAserial filename]
[-CAcreateserial] [-trustout] [-setalias arg] [-clrtrust] [-addtrust arg] [-clrreject]
[-addreject arg] [-rand files] [-writerand file] [-engine id] [-provider name]
[-provider-path path] [-propquery propq]
DESCRIPTION
This command is a multi-purposes certificate handling command. It can be used to print
certificate information, convert certificates to various forms, edit certificate trust
settings, generate certificates from scratch or from certificating requests and then self-
signing them or signing them like a "micro CA".
Since there are a large number of options they will split up into various sections.
OPTIONS
Input, Output, and General Purpose Options
-help
Print out a usage message.
-in filename|uri
This specifies the input to read a certificate from or the input file for reading a
certificate request if the -req flag is used. In both cases this defaults to standard
input.
This option cannot be combined with the -new flag.
-passin arg
The key and certificate file password source. For more information about the format
of arg see openssl-passphrase-options(1).
-new
Generate a certificate from scratch, not using an input certificate or certificate
request. So the -in option must not be used in this case. Instead, the -subj option
needs to be given. The public key to include can be given with the -force_pubkey
option and defaults to the key given with the -key (or -signkey) option, which implies
self-signature.
-x509toreq
Output a PKCS#10 certificate request (rather than a certificate). The -key (or
-signkey) option must be used to provide the private key for self-signing; the
corresponding public key is placed in the subjectPKInfo field.
X.509 extensions included in a certificate input are not copied by default. X.509
extensions to be added can be specified using the -extfile option.
-req
By default a certificate is expected on input. With this option a PKCS#10 certificate
request is expected instead, which must be correctly self-signed.
X.509 extensions included in the request are not copied by default. X.509 extensions
to be added can be specified using the -extfile option.
-copy_extensions arg
Determines how to handle X.509 extensions when converting from a certificate to a
request using the -x509toreq option or converting from a request to a certificate
using the -req option. If arg is none or this option is not present then extensions
are ignored. If arg is copy or copyall then all extensions are copied, except that
subject identifier and authority key identifier extensions are not taken over when
producing a certificate request.
The -ext option can be used to further restrict which extensions to copy.
-inform DER|PEM
The input file format; unspecified by default. See openssl-format-options(1) for
details.
-vfyopt nm:v
Pass options to the signature algorithm during verify operations. Names and values of
these options are algorithm-specific.
-key filename|uri
This option provides the private key for signing a new certificate or certificate
request. Unless -force_pubkey is given, the corresponding public key is placed in the
new certificate or certificate request, resulting in a self-signature.
This option cannot be used in conjunction with the -CA option.
It sets the issuer name to the subject name (i.e., makes it self-issued) and changes
the public key to the supplied value (unless overridden by -force_pubkey). Unless the
-preserve_dates option is supplied, it sets the validity start date to the current
time and the end date to a value determined by the -days option.
-signkey filename|uri
This option is an alias of -key.
-keyform DER|PEM|P12|ENGINE
The key input format; unspecified by default. See openssl-format-options(1) for
details.
-out filename
This specifies the output filename to write to or standard output by default.
-outform DER|PEM
The output format; the default is PEM. See openssl-format-options(1) for details.
-nocert
Do not output a certificate (except for printing as requested by below options).
-noout
This option prevents output except for printing as requested by below options.
Certificate Printing Options
Note: the -alias and -purpose options are also printing options but are described in the
"Trust Settings" section.
-dateopt
Specify the date output format. Values are: rfc_822 and iso_8601. Defaults to
rfc_822.
-text
Prints out the certificate in text form. Full details are printed including the public
key, signature algorithms, issuer and subject names, serial number any extensions
present and any trust settings.
-certopt option
Customise the print format used with -text. The option argument can be a single option
or multiple options separated by commas. The -certopt switch may be also be used more
than once to set multiple options. See the "Text Printing Flags" section for more
information.
-fingerprint
Calculates and prints the digest of the DER encoded version of the entire certificate
(see digest options). This is commonly called a "fingerprint". Because of the nature
of message digests, the fingerprint of a certificate is unique to that certificate and
two certificates with the same fingerprint can be considered to be the same.
-alias
Prints the certificate "alias" (nickname), if any.
-serial
Prints the certificate serial number.
-startdate
Prints out the start date of the certificate, that is the notBefore date.
-enddate
Prints out the expiry date of the certificate, that is the notAfter date.
-dates
Prints out the start and expiry dates of a certificate.
-subject
Prints the subject name.
-issuer
Prints the issuer name.
-nameopt option
This specifies how the subject or issuer names are displayed. See
openssl-namedisplay-options(1) for details.
-email
Prints the email address(es) if any.
-hash
Synonym for "-subject_hash" for backward compatibility reasons.
-subject_hash
Prints the "hash" of the certificate subject name. This is used in OpenSSL to form an
index to allow certificates in a directory to be looked up by subject name.
-subject_hash_old
Prints the "hash" of the certificate subject name using the older algorithm as used by
OpenSSL before version 1.0.0.
-issuer_hash
Prints the "hash" of the certificate issuer name.
-issuer_hash_old
Prints the "hash" of the certificate issuer name using the older algorithm as used by
OpenSSL before version 1.0.0.
-ext extensions
Prints out the certificate extensions in text form. Can also be used to restrict
which extensions to copy. Extensions are specified with a comma separated string,
e.g., "subjectAltName,subjectKeyIdentifier". See the x509v3_config(5) manual page for
the extension names.
-ocspid
Prints the OCSP hash values for the subject name and public key.
-ocsp_uri
Prints the OCSP responder address(es) if any.
-purpose
This option performs tests on the certificate extensions and outputs the results. For
a more complete description see "Certificate Extensions" in
openssl-verification-options(1).
-pubkey
Prints the certificate's SubjectPublicKeyInfo block in PEM format.
-modulus
This option prints out the value of the modulus of the public key contained in the
certificate.
Certificate Checking Options
-checkend arg
Checks if the certificate expires within the next arg seconds and exits nonzero if yes
it will expire or zero if not.
-checkhost host
Check that the certificate matches the specified host.
-checkemail email
Check that the certificate matches the specified email address.
-checkip ipaddr
Check that the certificate matches the specified IP address.
Certificate Output Options
-set_serial n
Specifies the serial number to use. This option can be used with the -key, -signkey,
or -CA options. If used in conjunction with the -CA option the serial number file (as
specified by the -CAserial option) is not used.
The serial number can be decimal or hex (if preceded by "0x").
-next_serial
Set the serial to be one more than the number in the certificate.
-days arg
Specifies the number of days until a newly generated certificate expires. The default
is 30. Cannot be used together with the -preserve_dates option.
-preserve_dates
When signing a certificate, preserve "notBefore" and "notAfter" dates of any input
certificate instead of adjusting them to current time and duration. Cannot be used
together with the -days option.
-subj arg
When a certificate is created set its subject name to the given value. When the
certificate is self-signed the issuer name is set to the same value.
The arg must be formatted as "/type0=value0/type1=value1/type2=...". Special
characters may be escaped by "\" (backslash), whitespace is retained. Empty values
are permitted, but the corresponding type will not be included in the certificate.
Giving a single "/" will lead to an empty sequence of RDNs (a NULL-DN). Multi-valued
RDNs can be formed by placing a "+" character instead of a "/" between the
AttributeValueAssertions (AVAs) that specify the members of the set. Example:
"/DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John Doe"
This option can be used in conjunction with the -force_pubkey option to create a
certificate even without providing an input certificate or certificate request.
-force_pubkey filename
When a certificate is created set its public key to the key in filename instead of the
key contained in the input or given with the -key (or -signkey) option.
This option is useful for creating self-issued certificates that are not self-signed,
for instance when the key cannot be used for signing, such as DH. It can also be used
in conjunction with b<-new> and -subj to directly generate a certificate containing
any desired public key.
-clrext
When transforming a certificate to a new certificate by default all certificate
extensions are retained.
When transforming a certificate or certificate request, the -clrext option prevents
taking over any extensions from the source. In any case, when producing a certificate
request, neither subject identifier nor authority key identifier extensions are
included.
-extfile filename
Configuration file containing certificate and request X.509 extensions to add.
-extensions section
The section in the extfile to add X.509 extensions from. If this option is not
specified then the extensions should either be contained in the unnamed (default)
section or the default section should contain a variable called "extensions" which
contains the section to use. See the x509v3_config(5) manual page for details of the
extension section format.
-sigopt nm:v
Pass options to the signature algorithm during sign operations. This option may be
given multiple times. Names and values provided using this option are algorithm-
specific.
-badsig
Corrupt the signature before writing it; this can be useful for testing.
-digest
The digest to use. This affects any signing or printing option that uses a message
digest, such as the -fingerprint, -key, and -CA options. Any digest supported by the
openssl-dgst(1) command can be used. If not specified then SHA1 is used with
-fingerprint or the default digest for the signing algorithm is used, typically
SHA256.
Micro-CA Options
-CA filename|uri
Specifies the "CA" certificate to be used for signing. When present, this behaves
like a "micro CA" as follows: The subject name of the "CA" certificate is placed as
issuer name in the new certificate, which is then signed using the "CA" key given as
detailed below.
This option cannot be used in conjunction with -key (or -signkey). This option is
normally combined with the -req option referencing a CSR. Without the -req option the
input must be an existing certificate unless the -new option is given, which generates
a certificate from scratch.
-CAform DER|PEM|P12,
The format for the CA certificate; unspecifed by default. See
openssl-format-options(1) for details.
-CAkey filename|uri
Sets the CA private key to sign a certificate with. The private key must match the
public key of the certificate given with -CA. If this option is not provided then the
key must be present in the -CA input.
-CAkeyform DER|PEM|P12|ENGINE
The format for the CA key; unspecified by default. See openssl-format-options(1) for
details.
-CAserial filename
Sets the CA serial number file to use.
When the -CA option is used to sign a certificate it uses a serial number specified in
a file. This file consists of one line containing an even number of hex digits with
the serial number to use. After each use the serial number is incremented and written
out to the file again.
The default filename consists of the CA certificate file base name with .srl appended.
For example if the CA certificate file is called mycacert.pem it expects to find a
serial number file called mycacert.srl.
-CAcreateserial
With this option the CA serial number file is created if it does not exist: it will
contain the serial number "02" and the certificate being signed will have the 1 as its
serial number. If the -CA option is specified and the serial number file does not
exist a random number is generated; this is the recommended practice.
Trust Settings
A trusted certificate is an ordinary certificate which has several additional pieces of
information attached to it such as the permitted and prohibited uses of the certificate
and possibly an "alias" (nickname).
Normally when a certificate is being verified at least one certificate must be "trusted".
By default a trusted certificate must be stored locally and must be a root CA: any
certificate chain ending in this CA is then usable for any purpose.
Trust settings currently are only used with a root CA. They allow a finer control over
the purposes the root CA can be used for. For example, a CA may be trusted for SSL client
but not SSL server use.
See openssl-verification-options(1) for more information on the meaning of trust settings.
Future versions of OpenSSL will recognize trust settings on any certificate: not just root
CAs.
-trustout
Mark any certificate PEM output as <trusted> certificate rather than ordinary. An
ordinary or trusted certificate can be input but by default an ordinary certificate is
output and any trust settings are discarded. With the -trustout option a trusted
certificate is output. A trusted certificate is automatically output if any trust
settings are modified.
-setalias arg
Sets the "alias" of the certificate. This will allow the certificate to be referred to
using a nickname for example "Steve's Certificate".
-clrtrust
Clears all the permitted or trusted uses of the certificate.
-addtrust arg
Adds a trusted certificate use. Any object name can be used here but currently only
clientAuth, serverAuth, emailProtection, and anyExtendedKeyUsage are defined. As of
OpenSSL 1.1.0, the last of these blocks all purposes when rejected or enables all
purposes when trusted. Other OpenSSL applications may define additional uses.
-clrreject
Clears all the prohibited or rejected uses of the certificate.
-addreject arg
Adds a prohibited trust anchor purpose. It accepts the same values as the -addtrust
option.
Generic options
-rand files, -writerand file
See "Random State Options" in openssl(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).
Text Printing Flags
As well as customising the name printing format, it is also possible to customise the
actual fields printed using the certopt option when the text option is present. The
default behaviour is to print all fields.
compatible
Use the old format. This is equivalent to specifying no printing options at all.
no_header
Don't print header information: that is the lines saying "Certificate" and "Data".
no_version
Don't print out the version number.
no_serial
Don't print out the serial number.
no_signame
Don't print out the signature algorithm used.
no_validity
Don't print the validity, that is the notBefore and notAfter fields.
no_subject
Don't print out the subject name.
no_issuer
Don't print out the issuer name.
no_pubkey
Don't print out the public key.
no_sigdump
Don't give a hexadecimal dump of the certificate signature.
no_aux
Don't print out certificate trust information.
no_extensions
Don't print out any X509V3 extensions.
ext_default
Retain default extension behaviour: attempt to print out unsupported certificate
extensions.
ext_error
Print an error message for unsupported certificate extensions.
ext_parse
ASN1 parse unsupported extensions.
ext_dump
Hex dump unsupported extensions.
ca_default
The value used by openssl-ca(1), equivalent to no_issuer, no_pubkey, no_header, and
no_version.
EXAMPLES
Note: in these examples the '\' means the example should be all on one line.
Print the contents of a certificate:
openssl x509 -in cert.pem -noout -text
Print the "Subject Alternative Name" extension of a certificate:
openssl x509 -in cert.pem -noout -ext subjectAltName
Print more extensions of a certificate:
openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType
Print the certificate serial number:
openssl x509 -in cert.pem -noout -serial
Print the certificate subject name:
openssl x509 -in cert.pem -noout -subject
Print the certificate subject name in RFC2253 form:
openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
Print the certificate subject name in oneline form on a terminal supporting UTF8:
openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
Print the certificate SHA1 fingerprint:
openssl x509 -sha1 -in cert.pem -noout -fingerprint
Convert a certificate from PEM to DER format:
openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
Convert a certificate to a certificate request:
openssl x509 -x509toreq -in cert.pem -out req.pem -key key.pem
Convert a certificate request into a self-signed certificate using extensions for a CA:
openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
-key key.pem -out cacert.pem
Sign a certificate request using the CA certificate above and add user certificate
extensions:
openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
-CA cacert.pem -CAkey key.pem -CAcreateserial
Set a certificate to be trusted for SSL client use and change set its alias to "Steve's
Class 1 CA"
openssl x509 -in cert.pem -addtrust clientAuth \
-setalias "Steve's Class 1 CA" -out trust.pem
NOTES
The conversion to UTF8 format used with the name options assumes that T61Strings use the
ISO8859-1 character set. This is wrong but Netscape and MSIE do this as do many
certificates. So although this is incorrect it is more likely to print the majority of
certificates correctly.
The -email option searches the subject name and the subject alternative name extension.
Only unique email addresses will be printed out: it will not print the same address more
than once.
BUGS
It is possible to produce invalid certificates or requests by specifying the wrong private
key, using unsuitable X.509 extensions, or using inconsistent options in some cases: these
should be checked.
There should be options to explicitly set such things as start and end dates rather than
an offset from the current time.
SEE ALSO
openssl(1), openssl-req(1), openssl-ca(1), openssl-genrsa(1), openssl-gendsa(1),
openssl-verify(1), x509v3_config(5)
HISTORY
The hash algorithm used in the -subject_hash and -issuer_hash options before OpenSSL 1.0.0
was based on the deprecated MD5 algorithm and the encoding of the distinguished name. In
OpenSSL 1.0.0 and later it is based on a canonical version of the DN using SHA1. This
means that any directories using the old form must have their links rebuilt using
openssl-rehash(1) or similar.
The -signkey option has been renamed to -key in OpenSSL 3.0, keeping the old name as an
alias.
The -engine option was deprecated in OpenSSL 3.0.
The -C option was removed in OpenSSL 3.0.
COPYRIGHT
Copyright 2000-2021 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>.
3.0.2 2025-09-18 OPENSSL-X509(1SSL)
Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
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