6 x509 - Certificate display and signing utility
12 [B<-inform DER|PEM|NET>]
13 [B<-outform DER|PEM|NET>]
16 [B<-CAkeyform DER|PEM>]
47 [B<-signkey filename>]
54 [B<-CAserial filename>]
55 [B<-force_pubkey key>]
62 [B<-extfile filename>]
63 [B<-extensions section>]
71 The B<x509> command is a multi purpose certificate utility. It can be
72 used to display certificate information, convert certificates to
73 various forms, sign certificate requests like a "mini CA" or edit
74 certificate trust settings.
76 Since there are a large number of options they will split up into
81 =head2 Input, Output, and General Purpose Options
87 Print out a usage message.
89 =item B<-inform DER|PEM|NET>
91 This specifies the input format normally the command will expect an X509
92 certificate but this can change if other options such as B<-req> are
93 present. The DER format is the DER encoding of the certificate and PEM
94 is the base64 encoding of the DER encoding with header and footer lines
95 added. The NET option is an obscure Netscape server format that is now
96 obsolete. The default format is PEM.
98 =item B<-outform DER|PEM|NET>
100 This specifies the output format, the options have the same meaning and default
101 as the B<-inform> option.
103 =item B<-in filename>
105 This specifies the input filename to read a certificate from or standard input
106 if this option is not specified.
108 =item B<-out filename>
110 This specifies the output filename to write to or standard output by
116 This affects any signing or display option that uses a message
117 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options.
118 Any digest supported by the OpenSSL B<dgst> command can be used.
119 If not specified then SHA1 is used with B<-fingerprint> or
120 the default digest for the signing algorithm is used, typically SHA256.
122 =item B<-rand file...>
124 A file or files containing random data used to seed the random number
126 Multiple files can be specified separated by an OS-dependent character.
127 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
130 =item [B<-writerand file>]
132 Writes random data to the specified I<file> upon exit.
133 This can be used with a subsequent B<-rand> flag.
137 Specifying an engine (by its unique B<id> string) will cause B<x509>
138 to attempt to obtain a functional reference to the specified engine,
139 thus initialising it if needed. The engine will then be set as the default
140 for all available algorithms.
142 =item B<-preserve_dates>
144 When signing a certificate, preserve the "notBefore" and "notAfter" dates instead
145 of adjusting them to current time and duration. Cannot be used with the B<-days> option.
149 =head2 Display Options
151 Note: the B<-alias> and B<-purpose> options are also display options
152 but are described in the B<TRUST SETTINGS> section.
158 Prints out the certificate in text form. Full details are output including the
159 public key, signature algorithms, issuer and subject names, serial number
160 any extensions present and any trust settings.
162 =item B<-ext extensions>
164 Prints out the certificate extensions in text form. Extensions are specified
165 with a comma separated string, e.g., "subjectAltName,subjectKeyIdentifier".
166 See the L<x509v3_config(5)> manual page for the extension names.
168 =item B<-certopt option>
170 Customise the output format used with B<-text>. The B<option> argument
171 can be a single option or multiple options separated by commas. The
172 B<-certopt> switch may be also be used more than once to set multiple
173 options. See the B<TEXT OPTIONS> section for more information.
177 This option prevents output of the encoded version of the request.
181 Outputs the certificate's SubjectPublicKeyInfo block in PEM format.
185 This option prints out the value of the modulus of the public key
186 contained in the certificate.
190 Outputs the certificate serial number.
192 =item B<-subject_hash>
194 Outputs the "hash" of the certificate subject name. This is used in OpenSSL to
195 form an index to allow certificates in a directory to be looked up by subject
198 =item B<-issuer_hash>
200 Outputs the "hash" of the certificate issuer name.
204 Outputs the OCSP hash values for the subject name and public key.
208 Synonym for "-subject_hash" for backward compatibility reasons.
210 =item B<-subject_hash_old>
212 Outputs the "hash" of the certificate subject name using the older algorithm
213 as used by OpenSSL before version 1.0.0.
215 =item B<-issuer_hash_old>
217 Outputs the "hash" of the certificate issuer name using the older algorithm
218 as used by OpenSSL before version 1.0.0.
222 Outputs the subject name.
226 Outputs the issuer name.
228 =item B<-nameopt option>
230 Option which determines how the subject or issuer names are displayed. The
231 B<option> argument can be a single option or multiple options separated by
232 commas. Alternatively the B<-nameopt> switch may be used more than once to
233 set multiple options. See the B<NAME OPTIONS> section for more information.
237 Outputs the email address(es) if any.
241 Outputs the OCSP responder address(es) if any.
245 Prints out the start date of the certificate, that is the notBefore date.
249 Prints out the expiry date of the certificate, that is the notAfter date.
253 Prints out the start and expiry dates of a certificate.
255 =item B<-checkend arg>
257 Checks if the certificate expires within the next B<arg> seconds and exits
258 non-zero if yes it will expire or zero if not.
260 =item B<-fingerprint>
262 Prints out the digest of the DER encoded version of the whole certificate
263 (see digest options).
267 This outputs the certificate in the form of a C source file.
271 =head2 Trust Settings
273 A B<trusted certificate> is an ordinary certificate which has several
274 additional pieces of information attached to it such as the permitted
275 and prohibited uses of the certificate and an "alias".
277 Normally when a certificate is being verified at least one certificate
278 must be "trusted". By default a trusted certificate must be stored
279 locally and must be a root CA: any certificate chain ending in this CA
280 is then usable for any purpose.
282 Trust settings currently are only used with a root CA. They allow a finer
283 control over the purposes the root CA can be used for. For example a CA
284 may be trusted for SSL client but not SSL server use.
286 See the description of the B<verify> utility for more information on the
287 meaning of trust settings.
289 Future versions of OpenSSL will recognize trust settings on any
290 certificate: not just root CAs.
297 This causes B<x509> to output a B<trusted> certificate. An ordinary
298 or trusted certificate can be input but by default an ordinary
299 certificate is output and any trust settings are discarded. With the
300 B<-trustout> option a trusted certificate is output. A trusted
301 certificate is automatically output if any trust settings are modified.
303 =item B<-setalias arg>
305 Sets the alias of the certificate. This will allow the certificate
306 to be referred to using a nickname for example "Steve's Certificate".
310 Outputs the certificate alias, if any.
314 Clears all the permitted or trusted uses of the certificate.
318 Clears all the prohibited or rejected uses of the certificate.
320 =item B<-addtrust arg>
322 Adds a trusted certificate use.
323 Any object name can be used here but currently only B<clientAuth> (SSL client
324 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
325 B<anyExtendedKeyUsage> are used.
326 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
327 enables all purposes when trusted.
328 Other OpenSSL applications may define additional uses.
330 =item B<-addreject arg>
332 Adds a prohibited use. It accepts the same values as the B<-addtrust>
337 This option performs tests on the certificate extensions and outputs
338 the results. For a more complete description see the B<CERTIFICATE
343 =head2 Signing Options
345 The B<x509> utility can be used to sign certificates and requests: it
346 can thus behave like a "mini CA".
350 =item B<-signkey filename>
352 This option causes the input file to be self signed using the supplied
355 If the input file is a certificate it sets the issuer name to the
356 subject name (i.e. makes it self signed) changes the public key to the
357 supplied value and changes the start and end dates. The start date is
358 set to the current time and the end date is set to a value determined
359 by the B<-days> option. Any certificate extensions are retained unless
360 the B<-clrext> option is supplied; this includes, for example, any existing
361 key identifier extensions.
363 If the input is a certificate request then a self signed certificate
364 is created using the supplied private key using the subject name in
369 The key password source. For more information about the format of B<arg>
370 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
374 Delete any extensions from a certificate. This option is used when a
375 certificate is being created from another certificate (for example with
376 the B<-signkey> or the B<-CA> options). Normally all extensions are
379 =item B<-keyform PEM|DER>
381 Specifies the format (DER or PEM) of the private key file used in the
386 Specifies the number of days to make a certificate valid for. The default
387 is 30 days. Cannot be used with the B<-preserve_dates> option.
391 Converts a certificate into a certificate request. The B<-signkey> option
392 is used to pass the required private key.
396 By default a certificate is expected on input. With this option a
397 certificate request is expected instead.
399 =item B<-set_serial n>
401 Specifies the serial number to use. This option can be used with either
402 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
403 option the serial number file (as specified by the B<-CAserial> or
404 B<-CAcreateserial> options) is not used.
406 The serial number can be decimal or hex (if preceded by B<0x>).
408 =item B<-CA filename>
410 Specifies the CA certificate to be used for signing. When this option is
411 present B<x509> behaves like a "mini CA". The input file is signed by this
412 CA using this option: that is its issuer name is set to the subject name
413 of the CA and it is digitally signed using the CAs private key.
415 This option is normally combined with the B<-req> option. Without the
416 B<-req> option the input is a certificate which must be self signed.
418 =item B<-CAkey filename>
420 Sets the CA private key to sign a certificate with. If this option is
421 not specified then it is assumed that the CA private key is present in
422 the CA certificate file.
424 =item B<-CAserial filename>
426 Sets the CA serial number file to use.
428 When the B<-CA> option is used to sign a certificate it uses a serial
429 number specified in a file. This file consist of one line containing
430 an even number of hex digits with the serial number to use. After each
431 use the serial number is incremented and written out to the file again.
433 The default filename consists of the CA certificate file base name with
434 ".srl" appended. For example if the CA certificate file is called
435 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
437 =item B<-CAcreateserial>
439 With this option the CA serial number file is created if it does not exist:
440 it will contain the serial number "02" and the certificate being signed will
441 have the 1 as its serial number. If the B<-CA> option is specified
442 and the serial number file does not exist a random number is generated;
443 this is the recommended practice.
445 =item B<-extfile filename>
447 File containing certificate extensions to use. If not specified then
448 no extensions are added to the certificate.
450 =item B<-extensions section>
452 The section to add certificate extensions from. If this option is not
453 specified then the extensions should either be contained in the unnamed
454 (default) section or the default section should contain a variable called
455 "extensions" which contains the section to use. See the
456 L<x509v3_config(5)> manual page for details of the
457 extension section format.
459 =item B<-force_pubkey key>
461 When a certificate is created set its public key to B<key> instead of the
462 key in the certificate or certificate request. This option is useful for
463 creating certificates where the algorithm can't normally sign requests, for
466 The format or B<key> can be specified using the B<-keyform> option.
472 The B<nameopt> command line switch determines how the subject and issuer
473 names are displayed. If no B<nameopt> switch is present the default "oneline"
474 format is used which is compatible with previous versions of OpenSSL.
475 Each option is described in detail below, all options can be preceded by
476 a B<-> to turn the option off. Only the first four will normally be used.
486 Displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
487 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
488 B<sep_comma_plus>, B<dn_rev> and B<sname>.
492 A oneline format which is more readable than RFC2253. It is equivalent to
493 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
494 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
495 options. This is the I<default> of no name options are given explicitly.
499 A multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
500 B<space_eq>, B<lname> and B<align>.
504 Escape the "special" characters required by RFC2253 in a field. That is
505 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
506 and a space character at the beginning or end of a string.
510 Escape the "special" characters required by RFC2254 in a field. That is
511 the B<NUL> character as well as and B<()*>.
515 Escape control characters. That is those with ASCII values less than
516 0x20 (space) and the delete (0x7f) character. They are escaped using the
517 RFC2253 \XX notation (where XX are two hex digits representing the
522 Escape characters with the MSB set, that is with ASCII values larger than
527 Escapes some characters by surrounding the whole string with B<"> characters,
528 without the option all escaping is done with the B<\> character.
532 Convert all strings to UTF8 format first. This is required by RFC2253. If
533 you are lucky enough to have a UTF8 compatible terminal then the use
534 of this option (and B<not> setting B<esc_msb>) may result in the correct
535 display of multibyte (international) characters. Is this option is not
536 present then multibyte characters larger than 0xff will be represented
537 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
538 Also if this option is off any UTF8Strings will be converted to their
539 character form first.
543 This option does not attempt to interpret multibyte characters in any
544 way. That is their content octets are merely dumped as though one octet
545 represents each character. This is useful for diagnostic purposes but
546 will result in rather odd looking output.
550 Show the type of the ASN1 character string. The type precedes the
551 field contents. For example "BMPSTRING: Hello World".
555 When this option is set any fields that need to be hexdumped will
556 be dumped using the DER encoding of the field. Otherwise just the
557 content octets will be displayed. Both options use the RFC2253
562 Dump non character string types (for example OCTET STRING) if this
563 option is not set then non character string types will be displayed
564 as though each content octet represents a single character.
568 Dump all fields. This option when used with B<dump_der> allows the
569 DER encoding of the structure to be unambiguously determined.
571 =item B<dump_unknown>
573 Dump any field whose OID is not recognised by OpenSSL.
575 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
578 These options determine the field separators. The first character is
579 between RDNs and the second between multiple AVAs (multiple AVAs are
580 very rare and their use is discouraged). The options ending in
581 "space" additionally place a space after the separator to make it
582 more readable. The B<sep_multiline> uses a linefeed character for
583 the RDN separator and a spaced B<+> for the AVA separator. It also
584 indents the fields by four characters. If no field separator is specified
585 then B<sep_comma_plus_space> is used by default.
589 Reverse the fields of the DN. This is required by RFC2253. As a side
590 effect this also reverses the order of multiple AVAs but this is
593 =item B<nofname>, B<sname>, B<lname>, B<oid>
595 These options alter how the field name is displayed. B<nofname> does
596 not display the field at all. B<sname> uses the "short name" form
597 (CN for commonName for example). B<lname> uses the long form.
598 B<oid> represents the OID in numerical form and is useful for
603 Align field values for a more readable output. Only usable with
608 Places spaces round the B<=> character which follows the field
615 As well as customising the name output format, it is also possible to
616 customise the actual fields printed using the B<certopt> options when
617 the B<text> option is present. The default behaviour is to print all fields.
623 Use the old format. This is equivalent to specifying no output options at all.
627 Don't print header information: that is the lines saying "Certificate"
632 Don't print out the version number.
636 Don't print out the serial number.
640 Don't print out the signature algorithm used.
644 Don't print the validity, that is the B<notBefore> and B<notAfter> fields.
648 Don't print out the subject name.
652 Don't print out the issuer name.
656 Don't print out the public key.
660 Don't give a hexadecimal dump of the certificate signature.
664 Don't print out certificate trust information.
666 =item B<no_extensions>
668 Don't print out any X509V3 extensions.
672 Retain default extension behaviour: attempt to print out unsupported
673 certificate extensions.
677 Print an error message for unsupported certificate extensions.
681 ASN1 parse unsupported extensions.
685 Hex dump unsupported extensions.
689 The value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
690 B<no_header>, and B<no_version>.
696 Note: in these examples the '\' means the example should be all on one
699 Display the contents of a certificate:
701 openssl x509 -in cert.pem -noout -text
703 Display the "Subject Alternative Name" extension of a certificate:
705 openssl x509 -in cert.pem -noout -ext subjectAltName
707 Display more extensions of a certificate:
709 openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType
711 Display the certificate serial number:
713 openssl x509 -in cert.pem -noout -serial
715 Display the certificate subject name:
717 openssl x509 -in cert.pem -noout -subject
719 Display the certificate subject name in RFC2253 form:
721 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
723 Display the certificate subject name in oneline form on a terminal
726 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
728 Display the certificate MD5 fingerprint:
730 openssl x509 -in cert.pem -noout -fingerprint
732 Display the certificate SHA1 fingerprint:
734 openssl x509 -sha1 -in cert.pem -noout -fingerprint
736 Convert a certificate from PEM to DER format:
738 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
740 Convert a certificate to a certificate request:
742 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
744 Convert a certificate request into a self signed certificate using
747 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
748 -signkey key.pem -out cacert.pem
750 Sign a certificate request using the CA certificate above and add user
751 certificate extensions:
753 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
754 -CA cacert.pem -CAkey key.pem -CAcreateserial
757 Set a certificate to be trusted for SSL client use and change set its alias to
760 openssl x509 -in cert.pem -addtrust clientAuth \
761 -setalias "Steve's Class 1 CA" -out trust.pem
765 The PEM format uses the header and footer lines:
767 -----BEGIN CERTIFICATE-----
768 -----END CERTIFICATE-----
770 it will also handle files containing:
772 -----BEGIN X509 CERTIFICATE-----
773 -----END X509 CERTIFICATE-----
775 Trusted certificates have the lines
777 -----BEGIN TRUSTED CERTIFICATE-----
778 -----END TRUSTED CERTIFICATE-----
780 The conversion to UTF8 format used with the name options assumes that
781 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
782 and MSIE do this as do many certificates. So although this is incorrect
783 it is more likely to display the majority of certificates correctly.
785 The B<-fingerprint> option takes the digest of the DER encoded certificate.
786 This is commonly called a "fingerprint". Because of the nature of message
787 digests the fingerprint of a certificate is unique to that certificate and
788 two certificates with the same fingerprint can be considered to be the same.
790 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
792 The B<-email> option searches the subject name and the subject alternative
793 name extension. Only unique email addresses will be printed out: it will
794 not print the same address more than once.
796 =head1 CERTIFICATE EXTENSIONS
798 The B<-purpose> option checks the certificate extensions and determines
799 what the certificate can be used for. The actual checks done are rather
800 complex and include various hacks and workarounds to handle broken
801 certificates and software.
803 The same code is used when verifying untrusted certificates in chains
804 so this section is useful if a chain is rejected by the verify code.
806 The basicConstraints extension CA flag is used to determine whether the
807 certificate can be used as a CA. If the CA flag is true then it is a CA,
808 if the CA flag is false then it is not a CA. B<All> CAs should have the
811 If the basicConstraints extension is absent then the certificate is
812 considered to be a "possible CA" other extensions are checked according
813 to the intended use of the certificate. A warning is given in this case
814 because the certificate should really not be regarded as a CA: however
815 it is allowed to be a CA to work around some broken software.
817 If the certificate is a V1 certificate (and thus has no extensions) and
818 it is self signed it is also assumed to be a CA but a warning is again
819 given: this is to work around the problem of Verisign roots which are V1
820 self signed certificates.
822 If the keyUsage extension is present then additional restraints are
823 made on the uses of the certificate. A CA certificate B<must> have the
824 keyCertSign bit set if the keyUsage extension is present.
826 The extended key usage extension places additional restrictions on the
827 certificate uses. If this extension is present (whether critical or not)
828 the key can only be used for the purposes specified.
830 A complete description of each test is given below. The comments about
831 basicConstraints and keyUsage and V1 certificates above apply to B<all>
839 The extended key usage extension must be absent or include the "web client
840 authentication" OID. keyUsage must be absent or it must have the
841 digitalSignature bit set. Netscape certificate type must be absent or it must
842 have the SSL client bit set.
844 =item B<SSL Client CA>
846 The extended key usage extension must be absent or include the "web client
847 authentication" OID. Netscape certificate type must be absent or it must have
848 the SSL CA bit set: this is used as a work around if the basicConstraints
853 The extended key usage extension must be absent or include the "web server
854 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
855 must have the digitalSignature, the keyEncipherment set or both bits set.
856 Netscape certificate type must be absent or have the SSL server bit set.
858 =item B<SSL Server CA>
860 The extended key usage extension must be absent or include the "web server
861 authentication" and/or one of the SGC OIDs. Netscape certificate type must
862 be absent or the SSL CA bit must be set: this is used as a work around if the
863 basicConstraints extension is absent.
865 =item B<Netscape SSL Server>
867 For Netscape SSL clients to connect to an SSL server it must have the
868 keyEncipherment bit set if the keyUsage extension is present. This isn't
869 always valid because some cipher suites use the key for digital signing.
870 Otherwise it is the same as a normal SSL server.
872 =item B<Common S/MIME Client Tests>
874 The extended key usage extension must be absent or include the "email
875 protection" OID. Netscape certificate type must be absent or should have the
876 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
877 then the SSL client bit is tolerated as an alternative but a warning is shown:
878 this is because some Verisign certificates don't set the S/MIME bit.
880 =item B<S/MIME Signing>
882 In addition to the common S/MIME client tests the digitalSignature bit must
883 be set if the keyUsage extension is present.
885 =item B<S/MIME Encryption>
887 In addition to the common S/MIME tests the keyEncipherment bit must be set
888 if the keyUsage extension is present.
892 The extended key usage extension must be absent or include the "email
893 protection" OID. Netscape certificate type must be absent or must have the
894 S/MIME CA bit set: this is used as a work around if the basicConstraints
899 The keyUsage extension must be absent or it must have the CRL signing bit
902 =item B<CRL Signing CA>
904 The normal CA tests apply. Except in this case the basicConstraints extension
911 Extensions in certificates are not transferred to certificate requests and
914 It is possible to produce invalid certificates or requests by specifying the
915 wrong private key or using inconsistent options in some cases: these should
918 There should be options to explicitly set such things as start and end
919 dates rather than an offset from the current time.
923 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
924 L<gendsa(1)>, L<verify(1)>,
929 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
930 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
931 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
932 canonical version of the DN using SHA1. This means that any directories using
933 the old form must have their links rebuilt using B<c_rehash> or similar.
937 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
939 Licensed under the OpenSSL license (the "License"). You may not use
940 this file except in compliance with the License. You can obtain a copy
941 in the file LICENSE in the source distribution or at
942 L<https://www.openssl.org/source/license.html>.