X509(1)				    OpenSSL			       X509(1)



NAME
       x509 - Certificate display and signing utility

SYNOPSIS
       openssl x509 [-inform DER|PEM|NET] [-outform DER|PEM|NET] [-keyform
       DER|PEM] [-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 filename] [-passin arg] [-x509toreq]
       [-req] [-CA filename] [-CAkey filename] [-CAcreateserial] [-CAserial
       filename] [-force_pubkey key] [-text] [-certopt option] [-C]
       [-md2|-md5|-sha1|-mdc2] [-clrext] [-extfile filename] [-extensions
       section] [-engine id]

DESCRIPTION
       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.

OPTIONS
   INPUT, OUTPUT AND GENERAL PURPOSE OPTIONS
       -inform DER|PEM|NET
	   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 NET option is an obscure Netscape server
	   format that is now obsolete.

       -outform DER|PEM|NET
	   This specifies the output format, the options have the same meaning
	   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.

       -md2|-md5|-sha1|-mdc2
	   the digest to use. This affects any signing or display option that
	   uses a message digest, such as the -fingerprint, -signkey and -CA
	   options. If not specified then SHA1 is used. If the key being used
	   to sign with is a DSA key then this option has no effect: SHA1 is
	   always used with DSA keys.  For full list of digests see openssl
	   dgst -h output.

       -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.

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

       -text
	   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.

       -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 information.

       -noout
	   this option prevents output of the encoded version of the request.

       -pubkey
	   outputs the 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.

       -serial
	   outputs the certificate serial number.

       -subject_hash
	   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.

       -issuer_hash
	   outputs the "hash" of the certificate issuer name.

       -ocspid
	   outputs the OCSP hash values for the subject name and public key.

       -hash
	   synonym for "-subject_hash" for backward compatibility reasons.

       -subject_hash_old
	   outputs the "hash" of the certificate subject name using the older
	   algorithm as used by OpenSSL versions before 1.0.0.

       -issuer_hash_old
	   outputs the "hash" of the certificate issuer name using the older
	   algorithm as used by OpenSSL versions before 1.0.0.

       -subject
	   outputs the subject name.

       -issuer
	   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.

       -email
	   outputs the email address(es) if any.

       -ocsp_uri
	   outputs the OCSP responder address(es) if any.

       -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.

       -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.

       -fingerprint
	   prints out the digest of the DER encoded version of the whole
	   certificate (see digest options).

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

   TRUST SETTINGS
       Please note these options are currently experimental and may well
       change.

       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 settings.

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

       -trustout
	   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".

       -alias
	   outputs the certificate alias, if any.

       -clrtrust
	   clears all the permitted or trusted uses of the certificate.

       -clrreject
	   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) and emailProtection (S/MIME email) are used.  Other
	   OpenSSL applications may define additional uses.

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

       -purpose
	   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 filename
	   this option causes the input file to be self signed using the
	   supplied private key.

	   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.

	   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.

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

       -clrext
	   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
	   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.

       -x509toreq
	   converts a certificate into a certificate request. The -signkey
	   option is used to pass the required private key.

       -req
	   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).
	   Negative serial numbers can also be specified but their use is not
	   recommended.

       -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 consist 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.
	   Normally if the -CA option is specified and the serial number file
	   does not exist it is an error.

       -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.

       compat
	   use the old format. This is equivalent to specifying no name
	   options at all.

       RFC2253
	   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.

       oneline
	   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.

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

       esc_2253
	   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.

       esc_ctrl
	   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).

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

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

       utf8
	   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 first.

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

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

       dump_unknown
	   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.

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

       space_eq
	   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.

       compatible
	   use the old format. This is equivalent to specifying no output
	   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 the ca utility, 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.

       Display the contents of a certificate:

	openssl x509 -in cert.pem -noout -text

       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 MD5 fingerprint:

	openssl x509 -in cert.pem -noout -fingerprint

       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 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 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

	-----BEGIN TRUSTED CERTIFICATE-----
	-----END TRUSTED CERTIFICATE-----

       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 -fingerprint option takes the digest of the DER encoded
       certificate.  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.

       The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.

       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.

CERTIFICATE EXTENSIONS
       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 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 present.

BUGS
       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.

       The code to implement the verify behaviour described in the TRUST
       SETTINGS is currently being developed. It thus describes the intended
       behaviour rather than the current behaviour. It is hoped that it will
       represent reality in OpenSSL 0.9.5 and later.

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

HISTORY
       Before OpenSSL 0.9.8, the default digest for RSA keys was MD5.

       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.



1.0.2k				  2023-11-15			       X509(1)