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] [-issuer] [-nameopt option] [-email]
       [-startdate] [-enddate] [-purpose] [-dates] [-modulus]
       [-fingerprint] [-alias] [-noout] [-trustout] [-clrtrust]
       [-clrreject] [-addtrust arg] [-addreject arg] [-setalias
       arg] [-days arg] [-signkey filename] [-x509toreq] [-req]
       [-CA filename] [-CAkey filename] [-CAcreateserial]
       [-CAserial filename] [-text] [-C] [-md2|-md5|-sha1|-mdc2]
       [-clrext] [-extfile filename] [-extensions section]


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.


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 MD5 is used. If the key being used to
           sign with is a DSA key then this option has no effect:



DISPLAY OPTIONS

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

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

       -modulus
           this option prints out the value of the modulus of the
           public key contained in the certificate.

       -serial
           outputs the certificate serial number.

       -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.

       -subject
           outputs the subject name.

       -issuer
           outputs the issuer name.

       -nameopt option
           option which determine how the subject or issuer names
           are displayed. This option 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.

       -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


       -fingerprint
           prints out the digest of the DER encoded version of
           the whole certificate.

       -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


       -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.

       -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.

           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.

       -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 filename
           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.

           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.


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_spc, spc_eq and sname
           options.

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

       esc_2253
           escape the "special" characters required by RFC2253 in
           a field That is ,+"<>;. Additionally # is escaped at
           the beginnging 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


       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.

       no_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 repesents 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 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.

       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.

       spc_eq
           places spaces round the = character which follows the
           field name.


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:


       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 sslclient \
               -alias "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

       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.

       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:

           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)



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