Provided by: openssl_1.0.2g-1ubuntu4.20_amd64 bug

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.

       -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,
           no_version, no_sigdump and no_signame.

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.