5 x509 - Certificate display and signing utility
11 [B<-inform DER|PEM|NET>]
12 [B<-outform DER|PEM|NET>]
15 [B<-CAkeyform DER|PEM>]
46 [B<-signkey filename>]
53 [B<-CAserial filename>]
54 [B<-force_pubkey key>]
60 [B<-extfile filename>]
61 [B<-extensions section>]
69 The B<x509> command is a multi purpose certificate utility. It can be
70 used to display certificate information, convert certificates to
71 various forms, sign certificate requests like a "mini CA" or edit
72 certificate trust settings.
74 Since there are a large number of options they will split up into
79 =head2 Input, Output, and General Purpose Options
85 Print out a usage message.
87 =item B<-inform DER|PEM|NET>
89 This specifies the input format normally the command will expect an X509
90 certificate but this can change if other options such as B<-req> are
91 present. The DER format is the DER encoding of the certificate and PEM
92 is the base64 encoding of the DER encoding with header and footer lines
93 added. The NET option is an obscure Netscape server format that is now
96 =item B<-outform DER|PEM|NET>
98 This specifies the output format, the options have the same meaning as the
101 =item B<-in filename>
103 This specifies the input filename to read a certificate from or standard input
104 if this option is not specified.
106 =item B<-out filename>
108 This specifies the output filename to write to or standard output by
114 This affects any signing or display option that uses a message
115 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options.
116 Any digest supported by the OpenSSL B<dgst> command can be used.
117 If not specified then SHA1 is used with B<-fingerprint> or
118 the default digest for the signing algorithm is used, typically SHA256.
120 =item B<-rand file...>
122 A file or files containing random data used to seed the random number
124 Multiple files can be specified separated by an OS-dependent character.
125 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
128 =item [B<-writerand file>]
130 Writes random data to the specified I<file> upon exit.
131 This can be used with a subsequent B<-rand> flag.
135 Specifying an engine (by its unique B<id> string) will cause B<x509>
136 to attempt to obtain a functional reference to the specified engine,
137 thus initialising it if needed. The engine will then be set as the default
138 for all available algorithms.
140 =item B<-preserve_dates>
142 When signing a certificate, preserve the "notBefore" and "notAfter" dates instead
143 of adjusting them to current time and duration. Cannot be used with the B<-days> option.
147 =head2 Display Options
149 Note: the B<-alias> and B<-purpose> options are also display options
150 but are described in the B<TRUST SETTINGS> section.
156 Prints out the certificate in text form. Full details are output including the
157 public key, signature algorithms, issuer and subject names, serial number
158 any extensions present and any trust settings.
160 =item B<-certopt option>
162 Customise the output format used with B<-text>. The B<option> argument
163 can be a single option or multiple options separated by commas. The
164 B<-certopt> switch may be also be used more than once to set multiple
165 options. See the B<TEXT OPTIONS> section for more information.
169 This option prevents output of the encoded version of the request.
173 Outputs the certificate's SubjectPublicKeyInfo block in PEM format.
177 This option prints out the value of the modulus of the public key
178 contained in the certificate.
182 Outputs the certificate serial number.
184 =item B<-subject_hash>
186 Outputs the "hash" of the certificate subject name. This is used in OpenSSL to
187 form an index to allow certificates in a directory to be looked up by subject
190 =item B<-issuer_hash>
192 Outputs the "hash" of the certificate issuer name.
196 Outputs the OCSP hash values for the subject name and public key.
200 Synonym for "-subject_hash" for backward compatibility reasons.
202 =item B<-subject_hash_old>
204 Outputs the "hash" of the certificate subject name using the older algorithm
205 as used by OpenSSL before version 1.0.0.
207 =item B<-issuer_hash_old>
209 Outputs the "hash" of the certificate issuer name using the older algorithm
210 as used by OpenSSL before version 1.0.0.
214 Outputs the subject name.
218 Outputs the issuer name.
220 =item B<-nameopt option>
222 Option which determines how the subject or issuer names are displayed. The
223 B<option> argument can be a single option or multiple options separated by
224 commas. Alternatively the B<-nameopt> switch may be used more than once to
225 set multiple options. See the B<NAME OPTIONS> section for more information.
229 Outputs the email address(es) if any.
233 Outputs the OCSP responder address(es) if any.
237 Prints out the start date of the certificate, that is the notBefore date.
241 Prints out the expiry date of the certificate, that is the notAfter date.
245 Prints out the start and expiry dates of a certificate.
247 =item B<-checkend arg>
249 Checks if the certificate expires within the next B<arg> seconds and exits
250 non-zero if yes it will expire or zero if not.
252 =item B<-fingerprint>
254 Prints out the digest of the DER encoded version of the whole certificate
255 (see digest options).
259 This outputs the certificate in the form of a C source file.
263 =head2 Trust Settings
265 A B<trusted certificate> is an ordinary certificate which has several
266 additional pieces of information attached to it such as the permitted
267 and prohibited uses of the certificate and an "alias".
269 Normally when a certificate is being verified at least one certificate
270 must be "trusted". By default a trusted certificate must be stored
271 locally and must be a root CA: any certificate chain ending in this CA
272 is then usable for any purpose.
274 Trust settings currently are only used with a root CA. They allow a finer
275 control over the purposes the root CA can be used for. For example a CA
276 may be trusted for SSL client but not SSL server use.
278 See the description of the B<verify> utility for more information on the
279 meaning of trust settings.
281 Future versions of OpenSSL will recognize trust settings on any
282 certificate: not just root CAs.
289 This causes B<x509> to output a B<trusted> certificate. An ordinary
290 or trusted certificate can be input but by default an ordinary
291 certificate is output and any trust settings are discarded. With the
292 B<-trustout> option a trusted certificate is output. A trusted
293 certificate is automatically output if any trust settings are modified.
295 =item B<-setalias arg>
297 Sets the alias of the certificate. This will allow the certificate
298 to be referred to using a nickname for example "Steve's Certificate".
302 Outputs the certificate alias, if any.
306 Clears all the permitted or trusted uses of the certificate.
310 Clears all the prohibited or rejected uses of the certificate.
312 =item B<-addtrust arg>
314 Adds a trusted certificate use.
315 Any object name can be used here but currently only B<clientAuth> (SSL client
316 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
317 B<anyExtendedKeyUsage> are used.
318 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
319 enables all purposes when trusted.
320 Other OpenSSL applications may define additional uses.
322 =item B<-addreject arg>
324 Adds a prohibited use. It accepts the same values as the B<-addtrust>
329 This option performs tests on the certificate extensions and outputs
330 the results. For a more complete description see the B<CERTIFICATE
335 =head2 Signing Options
337 The B<x509> utility can be used to sign certificates and requests: it
338 can thus behave like a "mini CA".
342 =item B<-signkey filename>
344 This option causes the input file to be self signed using the supplied
347 If the input file is a certificate it sets the issuer name to the
348 subject name (i.e. makes it self signed) changes the public key to the
349 supplied value and changes the start and end dates. The start date is
350 set to the current time and the end date is set to a value determined
351 by the B<-days> option. Any certificate extensions are retained unless
352 the B<-clrext> option is supplied; this includes, for example, any existing
353 key identifier extensions.
355 If the input is a certificate request then a self signed certificate
356 is created using the supplied private key using the subject name in
361 The key password source. For more information about the format of B<arg>
362 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
366 Delete any extensions from a certificate. This option is used when a
367 certificate is being created from another certificate (for example with
368 the B<-signkey> or the B<-CA> options). Normally all extensions are
371 =item B<-keyform PEM|DER>
373 Specifies the format (DER or PEM) of the private key file used in the
378 Specifies the number of days to make a certificate valid for. The default
379 is 30 days. Cannot be used with the B<-preserve_dates> option.
383 Converts a certificate into a certificate request. The B<-signkey> option
384 is used to pass the required private key.
388 By default a certificate is expected on input. With this option a
389 certificate request is expected instead.
391 =item B<-set_serial n>
393 Specifies the serial number to use. This option can be used with either
394 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
395 option the serial number file (as specified by the B<-CAserial> or
396 B<-CAcreateserial> options) is not used.
398 The serial number can be decimal or hex (if preceded by B<0x>).
400 =item B<-CA filename>
402 Specifies the CA certificate to be used for signing. When this option is
403 present B<x509> behaves like a "mini CA". The input file is signed by this
404 CA using this option: that is its issuer name is set to the subject name
405 of the CA and it is digitally signed using the CAs private key.
407 This option is normally combined with the B<-req> option. Without the
408 B<-req> option the input is a certificate which must be self signed.
410 =item B<-CAkey filename>
412 Sets the CA private key to sign a certificate with. If this option is
413 not specified then it is assumed that the CA private key is present in
414 the CA certificate file.
416 =item B<-CAserial filename>
418 Sets the CA serial number file to use.
420 When the B<-CA> option is used to sign a certificate it uses a serial
421 number specified in a file. This file consist of one line containing
422 an even number of hex digits with the serial number to use. After each
423 use the serial number is incremented and written out to the file again.
425 The default filename consists of the CA certificate file base name with
426 ".srl" appended. For example if the CA certificate file is called
427 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
429 =item B<-CAcreateserial>
431 With this option the CA serial number file is created if it does not exist:
432 it will contain the serial number "02" and the certificate being signed will
433 have the 1 as its serial number. If the B<-CA> option is specified
434 and the serial number file does not exist a random number is generated;
435 this is the recommended practice.
437 =item B<-extfile filename>
439 File containing certificate extensions to use. If not specified then
440 no extensions are added to the certificate.
442 =item B<-extensions section>
444 The section to add certificate extensions from. If this option is not
445 specified then the extensions should either be contained in the unnamed
446 (default) section or the default section should contain a variable called
447 "extensions" which contains the section to use. See the
448 L<x509v3_config(5)> manual page for details of the
449 extension section format.
451 =item B<-force_pubkey key>
453 When a certificate is created set its public key to B<key> instead of the
454 key in the certificate or certificate request. This option is useful for
455 creating certificates where the algorithm can't normally sign requests, for
458 The format or B<key> can be specified using the B<-keyform> option.
464 The B<nameopt> command line switch determines how the subject and issuer
465 names are displayed. If no B<nameopt> switch is present the default "oneline"
466 format is used which is compatible with previous versions of OpenSSL.
467 Each option is described in detail below, all options can be preceded by
468 a B<-> to turn the option off. Only the first four will normally be used.
478 Displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
479 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
480 B<sep_comma_plus>, B<dn_rev> and B<sname>.
484 A oneline format which is more readable than RFC2253. It is equivalent to
485 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
486 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
487 options. This is the I<default> of no name options are given explicitly.
491 A multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
492 B<space_eq>, B<lname> and B<align>.
496 Escape the "special" characters required by RFC2253 in a field. That is
497 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
498 and a space character at the beginning or end of a string.
502 Escape the "special" characters required by RFC2254 in a field. That is
503 the B<NUL> character as well as and B<()*>.
507 Escape control characters. That is those with ASCII values less than
508 0x20 (space) and the delete (0x7f) character. They are escaped using the
509 RFC2253 \XX notation (where XX are two hex digits representing the
514 Escape characters with the MSB set, that is with ASCII values larger than
519 Escapes some characters by surrounding the whole string with B<"> characters,
520 without the option all escaping is done with the B<\> character.
524 Convert all strings to UTF8 format first. This is required by RFC2253. If
525 you are lucky enough to have a UTF8 compatible terminal then the use
526 of this option (and B<not> setting B<esc_msb>) may result in the correct
527 display of multibyte (international) characters. Is this option is not
528 present then multibyte characters larger than 0xff will be represented
529 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
530 Also if this option is off any UTF8Strings will be converted to their
531 character form first.
535 This option does not attempt to interpret multibyte characters in any
536 way. That is their content octets are merely dumped as though one octet
537 represents each character. This is useful for diagnostic purposes but
538 will result in rather odd looking output.
542 Show the type of the ASN1 character string. The type precedes the
543 field contents. For example "BMPSTRING: Hello World".
547 When this option is set any fields that need to be hexdumped will
548 be dumped using the DER encoding of the field. Otherwise just the
549 content octets will be displayed. Both options use the RFC2253
554 Dump non character string types (for example OCTET STRING) if this
555 option is not set then non character string types will be displayed
556 as though each content octet represents a single character.
560 Dump all fields. This option when used with B<dump_der> allows the
561 DER encoding of the structure to be unambiguously determined.
563 =item B<dump_unknown>
565 Dump any field whose OID is not recognised by OpenSSL.
567 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
570 These options determine the field separators. The first character is
571 between RDNs and the second between multiple AVAs (multiple AVAs are
572 very rare and their use is discouraged). The options ending in
573 "space" additionally place a space after the separator to make it
574 more readable. The B<sep_multiline> uses a linefeed character for
575 the RDN separator and a spaced B<+> for the AVA separator. It also
576 indents the fields by four characters. If no field separator is specified
577 then B<sep_comma_plus_space> is used by default.
581 Reverse the fields of the DN. This is required by RFC2253. As a side
582 effect this also reverses the order of multiple AVAs but this is
585 =item B<nofname>, B<sname>, B<lname>, B<oid>
587 These options alter how the field name is displayed. B<nofname> does
588 not display the field at all. B<sname> uses the "short name" form
589 (CN for commonName for example). B<lname> uses the long form.
590 B<oid> represents the OID in numerical form and is useful for
595 Align field values for a more readable output. Only usable with
600 Places spaces round the B<=> character which follows the field
607 As well as customising the name output format, it is also possible to
608 customise the actual fields printed using the B<certopt> options when
609 the B<text> option is present. The default behaviour is to print all fields.
615 Use the old format. This is equivalent to specifying no output options at all.
619 Don't print header information: that is the lines saying "Certificate"
624 Don't print out the version number.
628 Don't print out the serial number.
632 Don't print out the signature algorithm used.
636 Don't print the validity, that is the B<notBefore> and B<notAfter> fields.
640 Don't print out the subject name.
644 Don't print out the issuer name.
648 Don't print out the public key.
652 Don't give a hexadecimal dump of the certificate signature.
656 Don't print out certificate trust information.
658 =item B<no_extensions>
660 Don't print out any X509V3 extensions.
664 Retain default extension behaviour: attempt to print out unsupported
665 certificate extensions.
669 Print an error message for unsupported certificate extensions.
673 ASN1 parse unsupported extensions.
677 Hex dump unsupported extensions.
681 The value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
682 B<no_header>, and B<no_version>.
688 Note: in these examples the '\' means the example should be all on one
691 Display the contents of a certificate:
693 openssl x509 -in cert.pem -noout -text
695 Display the certificate serial number:
697 openssl x509 -in cert.pem -noout -serial
699 Display the certificate subject name:
701 openssl x509 -in cert.pem -noout -subject
703 Display the certificate subject name in RFC2253 form:
705 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
707 Display the certificate subject name in oneline form on a terminal
710 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
712 Display the certificate MD5 fingerprint:
714 openssl x509 -in cert.pem -noout -fingerprint
716 Display the certificate SHA1 fingerprint:
718 openssl x509 -sha1 -in cert.pem -noout -fingerprint
720 Convert a certificate from PEM to DER format:
722 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
724 Convert a certificate to a certificate request:
726 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
728 Convert a certificate request into a self signed certificate using
731 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
732 -signkey key.pem -out cacert.pem
734 Sign a certificate request using the CA certificate above and add user
735 certificate extensions:
737 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
738 -CA cacert.pem -CAkey key.pem -CAcreateserial
741 Set a certificate to be trusted for SSL client use and change set its alias to
744 openssl x509 -in cert.pem -addtrust clientAuth \
745 -setalias "Steve's Class 1 CA" -out trust.pem
749 The PEM format uses the header and footer lines:
751 -----BEGIN CERTIFICATE-----
752 -----END CERTIFICATE-----
754 it will also handle files containing:
756 -----BEGIN X509 CERTIFICATE-----
757 -----END X509 CERTIFICATE-----
759 Trusted certificates have the lines
761 -----BEGIN TRUSTED CERTIFICATE-----
762 -----END TRUSTED CERTIFICATE-----
764 The conversion to UTF8 format used with the name options assumes that
765 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
766 and MSIE do this as do many certificates. So although this is incorrect
767 it is more likely to display the majority of certificates correctly.
769 The B<-fingerprint> option takes the digest of the DER encoded certificate.
770 This is commonly called a "fingerprint". Because of the nature of message
771 digests the fingerprint of a certificate is unique to that certificate and
772 two certificates with the same fingerprint can be considered to be the same.
774 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
776 The B<-email> option searches the subject name and the subject alternative
777 name extension. Only unique email addresses will be printed out: it will
778 not print the same address more than once.
780 =head1 CERTIFICATE EXTENSIONS
782 The B<-purpose> option checks the certificate extensions and determines
783 what the certificate can be used for. The actual checks done are rather
784 complex and include various hacks and workarounds to handle broken
785 certificates and software.
787 The same code is used when verifying untrusted certificates in chains
788 so this section is useful if a chain is rejected by the verify code.
790 The basicConstraints extension CA flag is used to determine whether the
791 certificate can be used as a CA. If the CA flag is true then it is a CA,
792 if the CA flag is false then it is not a CA. B<All> CAs should have the
795 If the basicConstraints extension is absent then the certificate is
796 considered to be a "possible CA" other extensions are checked according
797 to the intended use of the certificate. A warning is given in this case
798 because the certificate should really not be regarded as a CA: however
799 it is allowed to be a CA to work around some broken software.
801 If the certificate is a V1 certificate (and thus has no extensions) and
802 it is self signed it is also assumed to be a CA but a warning is again
803 given: this is to work around the problem of Verisign roots which are V1
804 self signed certificates.
806 If the keyUsage extension is present then additional restraints are
807 made on the uses of the certificate. A CA certificate B<must> have the
808 keyCertSign bit set if the keyUsage extension is present.
810 The extended key usage extension places additional restrictions on the
811 certificate uses. If this extension is present (whether critical or not)
812 the key can only be used for the purposes specified.
814 A complete description of each test is given below. The comments about
815 basicConstraints and keyUsage and V1 certificates above apply to B<all>
823 The extended key usage extension must be absent or include the "web client
824 authentication" OID. keyUsage must be absent or it must have the
825 digitalSignature bit set. Netscape certificate type must be absent or it must
826 have the SSL client bit set.
828 =item B<SSL Client CA>
830 The extended key usage extension must be absent or include the "web client
831 authentication" OID. Netscape certificate type must be absent or it must have
832 the SSL CA bit set: this is used as a work around if the basicConstraints
837 The extended key usage extension must be absent or include the "web server
838 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
839 must have the digitalSignature, the keyEncipherment set or both bits set.
840 Netscape certificate type must be absent or have the SSL server bit set.
842 =item B<SSL Server CA>
844 The extended key usage extension must be absent or include the "web server
845 authentication" and/or one of the SGC OIDs. Netscape certificate type must
846 be absent or the SSL CA bit must be set: this is used as a work around if the
847 basicConstraints extension is absent.
849 =item B<Netscape SSL Server>
851 For Netscape SSL clients to connect to an SSL server it must have the
852 keyEncipherment bit set if the keyUsage extension is present. This isn't
853 always valid because some cipher suites use the key for digital signing.
854 Otherwise it is the same as a normal SSL server.
856 =item B<Common S/MIME Client Tests>
858 The extended key usage extension must be absent or include the "email
859 protection" OID. Netscape certificate type must be absent or should have the
860 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
861 then the SSL client bit is tolerated as an alternative but a warning is shown:
862 this is because some Verisign certificates don't set the S/MIME bit.
864 =item B<S/MIME Signing>
866 In addition to the common S/MIME client tests the digitalSignature bit must
867 be set if the keyUsage extension is present.
869 =item B<S/MIME Encryption>
871 In addition to the common S/MIME tests the keyEncipherment bit must be set
872 if the keyUsage extension is present.
876 The extended key usage extension must be absent or include the "email
877 protection" OID. Netscape certificate type must be absent or must have the
878 S/MIME CA bit set: this is used as a work around if the basicConstraints
883 The keyUsage extension must be absent or it must have the CRL signing bit
886 =item B<CRL Signing CA>
888 The normal CA tests apply. Except in this case the basicConstraints extension
895 Extensions in certificates are not transferred to certificate requests and
898 It is possible to produce invalid certificates or requests by specifying the
899 wrong private key or using inconsistent options in some cases: these should
902 There should be options to explicitly set such things as start and end
903 dates rather than an offset from the current time.
907 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
908 L<gendsa(1)>, L<verify(1)>,
913 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
914 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
915 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
916 canonical version of the DN using SHA1. This means that any directories using
917 the old form must have their links rebuilt using B<c_rehash> or similar.
921 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
923 Licensed under the OpenSSL license (the "License"). You may not use
924 this file except in compliance with the License. You can obtain a copy
925 in the file LICENSE in the source distribution or at
926 L<https://www.openssl.org/source/license.html>.