Provided by: openssl_1.1.1f-1ubuntu2_amd64 bug


       openssl-x509, x509 - Certificate display and signing utility


       openssl x509 [-help] [-inform DER|PEM] [-outform DER|PEM] [-keyform DER|PEM|ENGINE]
       [-CAform DER|PEM] [-CAkeyform DER|PEM] [-in filename] [-out filename] [-serial] [-hash]
       [-subject_hash] [-issuer_hash] [-ocspid] [-subject] [-issuer] [-nameopt option] [-email]
       [-ocsp_uri] [-startdate] [-enddate] [-purpose] [-dates] [-checkend num] [-modulus]
       [-pubkey] [-fingerprint] [-alias] [-noout] [-trustout] [-clrtrust] [-clrreject] [-addtrust
       arg] [-addreject arg] [-setalias arg] [-days arg] [-set_serial n] [-signkey arg] [-passin
       arg] [-x509toreq] [-req] [-CA filename] [-CAkey filename] [-CAcreateserial] [-CAserial
       filename] [-force_pubkey key] [-text] [-ext extensions] [-certopt option] [-C] [-digest]
       [-clrext] [-extfile filename] [-extensions section] [-sigopt nm:v] [-rand file...]
       [-writerand file] [-engine id] [-preserve_dates]


       The x509 command is a multi purpose certificate utility. It can be used to display
       certificate information, convert certificates to various forms, sign certificate requests
       like a "mini CA" or edit certificate trust settings.

       Since there are a large number of options they will split up into various sections.


   Input, Output, and General Purpose Options
           Print out a usage message.

       -inform DER|PEM
           This specifies the input format normally the command will expect an X509 certificate
           but this can change if other options such as -req are present. The DER format is the
           DER encoding of the certificate and PEM is the base64 encoding of the DER encoding
           with header and footer lines added. The default format is PEM.

       -outform DER|PEM
           This specifies the output format, the options have the same meaning and default as the
           -inform option.

       -in filename
           This specifies the input filename to read a certificate from or standard input if this
           option is not specified.

       -out filename
           This specifies the output filename to write to or standard output by default.

           The digest to use.  This affects any signing or display option that uses a message
           digest, such as the -fingerprint, -signkey and -CA options.  Any digest supported by
           the OpenSSL dgst command can be used.  If not specified then SHA1 is used with
           -fingerprint or the default digest for the signing algorithm is used, typically

       -rand file...
           A file or files containing random data used to seed the random number generator.
           Multiple files can be specified separated by an OS-dependent character.  The separator
           is ; for MS-Windows, , for OpenVMS, and : for all others.

       [-writerand file]
           Writes random data to the specified file upon exit.  This can be used with a
           subsequent -rand flag.

       -engine id
           Specifying an engine (by its unique id string) will cause x509 to attempt to obtain a
           functional reference to the specified engine, thus initialising it if needed. The
           engine will then be set as the default for all available algorithms.

           When signing a certificate, preserve the "notBefore" and "notAfter" dates instead of
           adjusting them to current time and duration. Cannot be used with the -days option.

   Display Options
       Note: the -alias and -purpose options are also display options but are described in the
       TRUST SETTINGS section.

           Prints out the certificate in text form. Full details are output including the public
           key, signature algorithms, issuer and subject names, serial number any extensions
           present and any trust settings.

       -ext extensions
           Prints out the certificate extensions in text form. Extensions are specified with a
           comma separated string, e.g., "subjectAltName,subjectKeyIdentifier".  See the
           x509v3_config(5) manual page for the extension names.

       -certopt option
           Customise the output 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 OPTIONS section for more

           This option prevents output of the encoded version of the certificate.

           Outputs the certificate's SubjectPublicKeyInfo block in PEM format.

           This option prints out the value of the modulus of the public key contained in the

           Outputs the certificate serial number.

           Outputs 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.

           Outputs the "hash" of the certificate issuer name.

           Outputs the OCSP hash values for the subject name and public key.

           Synonym for "-subject_hash" for backward compatibility reasons.

           Outputs the "hash" of the certificate subject name using the older algorithm as used
           by OpenSSL before version 1.0.0.

           Outputs the "hash" of the certificate issuer name using the older algorithm as used by
           OpenSSL before version 1.0.0.

           Outputs the subject name.

           Outputs the issuer name.

       -nameopt option
           Option which determines how the subject or issuer names are displayed. The option
           argument can be a single option or multiple options separated by commas.
           Alternatively the -nameopt switch may be used more than once to set multiple options.
           See the NAME OPTIONS section for more information.

           Outputs the email address(es) if any.

           Outputs the OCSP responder address(es) if any.

           Prints out the start date of the certificate, that is the notBefore date.

           Prints out the expiry date of the certificate, that is the notAfter date.

           Prints out the start and expiry dates of a certificate.

       -checkend arg
           Checks if the certificate expires within the next arg seconds and exits non-zero if
           yes it will expire or zero if not.

           Calculates and outputs 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.

       -C  This outputs the certificate in the form of a C source file.

   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 an "alias".

       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 the description of the verify utility for more information on the meaning of trust

       Future versions of OpenSSL will recognize trust settings on any certificate: not just root

           This causes x509 to output a trusted certificate. 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".

           Outputs the certificate alias, if any.

           Clears all the permitted or trusted uses of the certificate.

           Clears all the prohibited or rejected uses of the certificate.

       -addtrust arg
           Adds a trusted certificate use.  Any object name can be used here but currently only
           clientAuth (SSL client use), serverAuth (SSL server use), emailProtection (S/MIME
           email) and anyExtendedKeyUsage are used.  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.

       -addreject arg
           Adds a prohibited use. It accepts the same values as the -addtrust option.

           This option performs tests on the certificate extensions and outputs the results. For
           a more complete description see the CERTIFICATE EXTENSIONS section.

   Signing Options
       The x509 utility can be used to sign certificates and requests: it can thus behave like a
       "mini CA".

       -signkey arg
           This option causes the input file to be self signed using the supplied private key or
           engine. The private key's format is specified with the -keyform option.

           If the input file is a certificate it sets the issuer name to the subject name (i.e.
           makes it self signed) changes the public key to the supplied value and changes the
           start and end dates. The start date is set to the current time and the end date is set
           to a value determined by the -days option. Any certificate extensions are retained
           unless the -clrext option is supplied; this includes, for example, any existing key
           identifier extensions.

           If the input is a certificate request then a self signed certificate is created using
           the supplied private key using the subject name in the request.

       -sigopt nm:v
           Pass options to the signature algorithm during sign or verify operations.  Names and
           values of these options are algorithm-specific.

       -passin arg
           The key password source. For more information about the format of arg see the PASS
           PHRASE ARGUMENTS section in openssl(1).

           Delete any extensions from a certificate. This option is used when a certificate is
           being created from another certificate (for example with the -signkey or the -CA
           options). Normally all extensions are retained.

       -keyform PEM|DER|ENGINE
           Specifies the format (DER or PEM) of the private key file used in the -signkey option.

       -days arg
           Specifies the number of days to make a certificate valid for. The default is 30 days.
           Cannot be used with the -preserve_dates option.

           Converts a certificate into a certificate request. The -signkey option is used to pass
           the required private key.

           By default a certificate is expected on input. With this option a certificate request
           is expected instead.

       -set_serial n
           Specifies the serial number to use. This option can be used with either the -signkey
           or -CA options. If used in conjunction with the -CA option the serial number file (as
           specified by the -CAserial or -CAcreateserial options) is not used.

           The serial number can be decimal or hex (if preceded by 0x).

       -CA filename
           Specifies the CA certificate to be used for signing. When this option is present x509
           behaves like a "mini CA". The input file is signed by this CA using this option: that
           is its issuer name is set to the subject name of the CA and it is digitally signed
           using the CAs private key.

           This option is normally combined with the -req option. Without the -req option the
           input is a certificate which must be self signed.

       -CAkey filename
           Sets the CA private key to sign a certificate with. If this option is not specified
           then it is assumed that the CA private key is present in the CA certificate file.

       -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 "".

           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.

       -extfile filename
           File containing certificate extensions to use. If not specified then no extensions are
           added to the certificate.

       -extensions section
           The section to add certificate 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.

       -force_pubkey key
           When a certificate is created set its public key to key instead of the key in the
           certificate or certificate request. This option is useful for creating certificates
           where the algorithm can't normally sign requests, for example DH.

           The format or key can be specified using the -keyform option.

   Name Options
       The nameopt command line switch determines how the subject and issuer names are displayed.
       If no nameopt switch is present the default "oneline" format is used which is compatible
       with previous versions of OpenSSL.  Each option is described in detail below, all options
       can be preceded by a - to turn the option off. Only the first four will normally be used.

           Use the old format.

           Displays names compatible with RFC2253 equivalent to esc_2253, esc_ctrl, esc_msb,
           utf8, dump_nostr, dump_unknown, dump_der, sep_comma_plus, dn_rev and sname.

           A oneline format which is more readable than RFC2253. It is equivalent to specifying
           the  esc_2253, esc_ctrl, esc_msb, utf8, dump_nostr, dump_der, use_quote,
           sep_comma_plus_space, space_eq and sname options.  This is the default of no name
           options are given explicitly.

           A multiline format. It is equivalent esc_ctrl, esc_msb, sep_multiline, space_eq, lname
           and align.

           Escape the "special" characters required by RFC2253 in a field. That is ,+"<>;.
           Additionally # is escaped at the beginning of a string and a space character at the
           beginning or end of a string.

           Escape the "special" characters required by RFC2254 in a field. That is the NUL
           character as well as and ()*.

           Escape control characters. That is those with ASCII values less than 0x20 (space) and
           the delete (0x7f) character. They are escaped using the RFC2253 \XX notation (where XX
           are two hex digits representing the character value).

           Escape characters with the MSB set, that is with ASCII values larger than 127.

           Escapes some characters by surrounding the whole string with " characters, without the
           option all escaping is done with the \ character.

           Convert all strings to UTF8 format first. This is required by RFC2253. If you are
           lucky enough to have a UTF8 compatible terminal then the use of this option (and not
           setting esc_msb) may result in the correct display of multibyte (international)
           characters. Is this option is not present then multibyte characters larger than 0xff
           will be represented using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
           Also if this option is off any UTF8Strings will be converted to their character form

           This option does not attempt to interpret multibyte characters in any way. That is
           their content octets are merely dumped as though one octet represents each character.
           This is useful for diagnostic purposes but will result in rather odd looking output.

           Show the type of the ASN1 character string. The type precedes the field contents. For
           example "BMPSTRING: Hello World".

           When this option is set any fields that need to be hexdumped will be dumped using the
           DER encoding of the field. Otherwise just the content octets will be displayed. Both
           options use the RFC2253 #XXXX... format.

           Dump non character string types (for example OCTET STRING) if this option is not set
           then non character string types will be displayed as though each content octet
           represents a single character.

           Dump all fields. This option when used with dump_der allows the DER encoding of the
           structure to be unambiguously determined.

           Dump any field whose OID is not recognised by OpenSSL.

       sep_comma_plus, sep_comma_plus_space, sep_semi_plus_space, sep_multiline
           These options determine the field separators. The first character is between RDNs and
           the second between multiple AVAs (multiple AVAs are very rare and their use is
           discouraged). The options ending in "space" additionally place a space after the
           separator to make it more readable. The sep_multiline uses a linefeed character for
           the RDN separator and a spaced + for the AVA separator. It also indents the fields by
           four characters. If no field separator is specified then sep_comma_plus_space is used
           by default.

           Reverse the fields of the DN. This is required by RFC2253. As a side effect this also
           reverses the order of multiple AVAs but this is permissible.

       nofname, sname, lname, oid
           These options alter how the field name is displayed. nofname does not display the
           field at all. sname uses the "short name" form (CN for commonName for example). lname
           uses the long form.  oid represents the OID in numerical form and is useful for
           diagnostic purpose.

           Align field values for a more readable output. Only usable with sep_multiline.

           Places spaces round the = character which follows the field name.

   Text Options
       As well as customising the name output format, it is also possible to customise the actual
       fields printed using the certopt options when the text option is present. The default
       behaviour is to print all fields.

           Use the old format. This is equivalent to specifying no output options at all.

           Don't print header information: that is the lines saying "Certificate" and "Data".

           Don't print out the version number.

           Don't print out the serial number.

           Don't print out the signature algorithm used.

           Don't print the validity, that is the notBefore and notAfter fields.

           Don't print out the subject name.

           Don't print out the issuer name.

           Don't print out the public key.

           Don't give a hexadecimal dump of the certificate signature.

           Don't print out certificate trust information.

           Don't print out any X509V3 extensions.

           Retain default extension behaviour: attempt to print out unsupported certificate

           Print an error message for unsupported certificate extensions.

           ASN1 parse unsupported extensions.

           Hex dump unsupported extensions.

           The value used by the ca utility, equivalent to no_issuer, no_pubkey, no_header, and


       Note: in these examples the '\' means the example should be all on one line.

       Display the contents of a certificate:

        openssl x509 -in cert.pem -noout -text

       Display the "Subject Alternative Name" extension of a certificate:

        openssl x509 -in cert.pem -noout -ext subjectAltName

       Display more extensions of a certificate:

        openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType

       Display the certificate serial number:

        openssl x509 -in cert.pem -noout -serial

       Display the certificate subject name:

        openssl x509 -in cert.pem -noout -subject

       Display the certificate subject name in RFC2253 form:

        openssl x509 -in cert.pem -noout -subject -nameopt RFC2253

       Display the certificate subject name in oneline form on a terminal supporting UTF8:

        openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb

       Display 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 -signkey 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 \
               -signkey key.pem -out cacert.pem

       Sign a certificate request using the CA certificate above and add user certificate

        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


       The PEM format uses the header and footer lines:

        -----BEGIN CERTIFICATE-----

        -----END CERTIFICATE-----
       it will also handle files containing:

        -----BEGIN X509 CERTIFICATE-----

        -----END X509 CERTIFICATE-----
       Trusted certificates have the lines


       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 display 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.


       The -purpose option checks the certificate extensions and determines what the certificate
       can be used for. The actual checks done are rather complex and include various hacks and
       workarounds to handle broken certificates and software.

       The same code is used when verifying untrusted certificates in chains so this section is
       useful if a chain is rejected by the verify code.

       The basicConstraints extension CA flag is used to determine whether the certificate can be
       used as a CA. If the CA flag is true then it is a CA, if the CA flag is false then it is
       not a CA. All CAs should have the CA flag set to true.

       If the basicConstraints extension is absent then the certificate is considered to be a
       "possible CA" other extensions are checked according to the intended use of the
       certificate. A warning is given in this case because the certificate should really not be
       regarded as a CA: however it is allowed to be a CA to work around some broken software.

       If the certificate is a V1 certificate (and thus has no extensions) and it is self signed
       it is also assumed to be a CA but a warning is again given: this is to work around the
       problem of Verisign roots which are V1 self signed certificates.

       If the keyUsage extension is present then additional restraints are made on the uses of
       the certificate. A CA certificate must have the keyCertSign bit set if the keyUsage
       extension is present.

       The extended key usage extension places additional restrictions on the certificate uses.
       If this extension is present (whether critical or not) the key can only be used for the
       purposes specified.

       A complete description of each test is given below. The comments about basicConstraints
       and keyUsage and V1 certificates above apply to all CA certificates.

       SSL Client
           The extended key usage extension must be absent or include the "web client
           authentication" OID.  keyUsage must be absent or it must have the digitalSignature bit
           set. Netscape certificate type must be absent or it must have the SSL client bit set.

       SSL Client CA
           The extended key usage extension must be absent or include the "web client
           authentication" OID. Netscape certificate type must be absent or it must have the SSL
           CA bit set: this is used as a work around if the basicConstraints extension is absent.

       SSL Server
           The extended key usage extension must be absent or include the "web server
           authentication" and/or one of the SGC OIDs.  keyUsage must be absent or it must have
           the digitalSignature, the keyEncipherment set or both bits set.  Netscape certificate
           type must be absent or have the SSL server bit set.

       SSL Server CA
           The extended key usage extension must be absent or include the "web server
           authentication" and/or one of the SGC OIDs.  Netscape certificate type must be absent
           or the SSL CA bit must be set: this is used as a work around if the basicConstraints
           extension is absent.

       Netscape SSL Server
           For Netscape SSL clients to connect to an SSL server it must have the keyEncipherment
           bit set if the keyUsage extension is present. This isn't always valid because some
           cipher suites use the key for digital signing.  Otherwise it is the same as a normal
           SSL server.

       Common S/MIME Client Tests
           The extended key usage extension must be absent or include the "email protection" OID.
           Netscape certificate type must be absent or should have the S/MIME bit set. If the
           S/MIME bit is not set in Netscape certificate type then the SSL client bit is
           tolerated as an alternative but a warning is shown: this is because some Verisign
           certificates don't set the S/MIME bit.

       S/MIME Signing
           In addition to the common S/MIME client tests the digitalSignature bit or the
           nonRepudiation bit must be set if the keyUsage extension is present.

       S/MIME Encryption
           In addition to the common S/MIME tests the keyEncipherment bit must be set if the
           keyUsage extension is present.

       S/MIME CA
           The extended key usage extension must be absent or include the "email protection" OID.
           Netscape certificate type must be absent or must have the S/MIME CA bit set: this is
           used as a work around if the basicConstraints extension is absent.

       CRL Signing
           The keyUsage extension must be absent or it must have the CRL signing bit set.

       CRL Signing CA
           The normal CA tests apply. Except in this case the basicConstraints extension must be


       Extensions in certificates are not transferred to certificate requests and vice versa.

       It is possible to produce invalid certificates or requests by specifying the wrong private
       key 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.


       req(1), ca(1), genrsa(1), gendsa(1), verify(1), x509v3_config(5)


       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 c_rehash
       or similar.


       Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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 <>.