6 x509 - Certificate display and signing utility
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>
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 default format is PEM.
97 =item B<-outform DER|PEM>
99 This specifies the output format, the options have the same meaning and default
100 as the B<-inform> option.
102 =item B<-in filename>
104 This specifies the input filename to read a certificate from or standard input
105 if this option is not specified.
107 =item B<-out filename>
109 This specifies the output filename to write to or standard output by
115 This affects any signing or display option that uses a message
116 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options.
117 Any digest supported by the OpenSSL B<dgst> command can be used.
118 If not specified then SHA1 is used with B<-fingerprint> or
119 the default digest for the signing algorithm is used, typically SHA256.
121 =item B<-rand file...>
123 A file or files containing random data used to seed the random number
125 Multiple files can be specified separated by an OS-dependent character.
126 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
129 =item [B<-writerand file>]
131 Writes random data to the specified I<file> upon exit.
132 This can be used with a subsequent B<-rand> flag.
136 Specifying an engine (by its unique B<id> string) will cause B<x509>
137 to attempt to obtain a functional reference to the specified engine,
138 thus initialising it if needed. The engine will then be set as the default
139 for all available algorithms.
141 =item B<-preserve_dates>
143 When signing a certificate, preserve the "notBefore" and "notAfter" dates instead
144 of adjusting them to current time and duration. Cannot be used with the B<-days> option.
148 =head2 Display Options
150 Note: the B<-alias> and B<-purpose> options are also display options
151 but are described in the B<TRUST SETTINGS> section.
157 Prints out the certificate in text form. Full details are output including the
158 public key, signature algorithms, issuer and subject names, serial number
159 any extensions present and any trust settings.
161 =item B<-ext extensions>
163 Prints out the certificate extensions in text form. Extensions are specified
164 with a comma separated string, e.g., "subjectAltName,subjectKeyIdentifier".
165 See the L<x509v3_config(5)> manual page for the extension names.
167 =item B<-certopt option>
169 Customise the output format used with B<-text>. The B<option> argument
170 can be a single option or multiple options separated by commas. The
171 B<-certopt> switch may be also be used more than once to set multiple
172 options. See the B<TEXT OPTIONS> section for more information.
176 This option prevents output of the encoded version of the certificate.
180 Outputs the certificate's SubjectPublicKeyInfo block in PEM format.
184 This option prints out the value of the modulus of the public key
185 contained in the certificate.
189 Outputs the certificate serial number.
191 =item B<-subject_hash>
193 Outputs the "hash" of the certificate subject name. This is used in OpenSSL to
194 form an index to allow certificates in a directory to be looked up by subject
197 =item B<-issuer_hash>
199 Outputs the "hash" of the certificate issuer name.
203 Outputs the OCSP hash values for the subject name and public key.
207 Synonym for "-subject_hash" for backward compatibility reasons.
209 =item B<-subject_hash_old>
211 Outputs the "hash" of the certificate subject name using the older algorithm
212 as used by OpenSSL before version 1.0.0.
214 =item B<-issuer_hash_old>
216 Outputs the "hash" of the certificate issuer name using the older algorithm
217 as used by OpenSSL before version 1.0.0.
221 Outputs the subject name.
225 Outputs the issuer name.
227 =item B<-nameopt option>
229 Option which determines how the subject or issuer names are displayed. The
230 B<option> argument can be a single option or multiple options separated by
231 commas. Alternatively the B<-nameopt> switch may be used more than once to
232 set multiple options. See the B<NAME OPTIONS> section for more information.
236 Outputs the email address(es) if any.
240 Outputs the OCSP responder address(es) if any.
244 Prints out the start date of the certificate, that is the notBefore date.
248 Prints out the expiry date of the certificate, that is the notAfter date.
252 Prints out the start and expiry dates of a certificate.
254 =item B<-checkend arg>
256 Checks if the certificate expires within the next B<arg> seconds and exits
257 non-zero if yes it will expire or zero if not.
259 =item B<-fingerprint>
261 Calculates and outputs the digest of the DER encoded version of the entire
262 certificate (see digest options).
263 This is commonly called a "fingerprint". Because of the nature of message
264 digests, the fingerprint of a certificate is unique to that certificate and
265 two certificates with the same fingerprint can be considered to be the same.
269 This outputs the certificate in the form of a C source file.
273 =head2 Trust Settings
275 A B<trusted certificate> is an ordinary certificate which has several
276 additional pieces of information attached to it such as the permitted
277 and prohibited uses of the certificate and an "alias".
279 Normally when a certificate is being verified at least one certificate
280 must be "trusted". By default a trusted certificate must be stored
281 locally and must be a root CA: any certificate chain ending in this CA
282 is then usable for any purpose.
284 Trust settings currently are only used with a root CA. They allow a finer
285 control over the purposes the root CA can be used for. For example a CA
286 may be trusted for SSL client but not SSL server use.
288 See the description of the B<verify> utility for more information on the
289 meaning of trust settings.
291 Future versions of OpenSSL will recognize trust settings on any
292 certificate: not just root CAs.
299 This causes B<x509> to output a B<trusted> certificate. An ordinary
300 or trusted certificate can be input but by default an ordinary
301 certificate is output and any trust settings are discarded. With the
302 B<-trustout> option a trusted certificate is output. A trusted
303 certificate is automatically output if any trust settings are modified.
305 =item B<-setalias arg>
307 Sets the alias of the certificate. This will allow the certificate
308 to be referred to using a nickname for example "Steve's Certificate".
312 Outputs the certificate alias, if any.
316 Clears all the permitted or trusted uses of the certificate.
320 Clears all the prohibited or rejected uses of the certificate.
322 =item B<-addtrust arg>
324 Adds a trusted certificate use.
325 Any object name can be used here but currently only B<clientAuth> (SSL client
326 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
327 B<anyExtendedKeyUsage> are used.
328 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
329 enables all purposes when trusted.
330 Other OpenSSL applications may define additional uses.
332 =item B<-addreject arg>
334 Adds a prohibited use. It accepts the same values as the B<-addtrust>
339 This option performs tests on the certificate extensions and outputs
340 the results. For a more complete description see the B<CERTIFICATE
345 =head2 Signing Options
347 The B<x509> utility can be used to sign certificates and requests: it
348 can thus behave like a "mini CA".
352 =item B<-signkey filename>
354 This option causes the input file to be self signed using the supplied
357 If the input file is a certificate it sets the issuer name to the
358 subject name (i.e. makes it self signed) changes the public key to the
359 supplied value and changes the start and end dates. The start date is
360 set to the current time and the end date is set to a value determined
361 by the B<-days> option. Any certificate extensions are retained unless
362 the B<-clrext> option is supplied; this includes, for example, any existing
363 key identifier extensions.
365 If the input is a certificate request then a self signed certificate
366 is created using the supplied private key using the subject name in
371 The key password source. For more information about the format of B<arg>
372 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
376 Delete any extensions from a certificate. This option is used when a
377 certificate is being created from another certificate (for example with
378 the B<-signkey> or the B<-CA> options). Normally all extensions are
381 =item B<-keyform PEM|DER>
383 Specifies the format (DER or PEM) of the private key file used in the
388 Specifies the number of days to make a certificate valid for. The default
389 is 30 days. Cannot be used with the B<-preserve_dates> option.
393 Converts a certificate into a certificate request. The B<-signkey> option
394 is used to pass the required private key.
398 By default a certificate is expected on input. With this option a
399 certificate request is expected instead.
401 =item B<-set_serial n>
403 Specifies the serial number to use. This option can be used with either
404 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
405 option the serial number file (as specified by the B<-CAserial> or
406 B<-CAcreateserial> options) is not used.
408 The serial number can be decimal or hex (if preceded by B<0x>).
410 =item B<-CA filename>
412 Specifies the CA certificate to be used for signing. When this option is
413 present B<x509> behaves like a "mini CA". The input file is signed by this
414 CA using this option: that is its issuer name is set to the subject name
415 of the CA and it is digitally signed using the CAs private key.
417 This option is normally combined with the B<-req> option. Without the
418 B<-req> option the input is a certificate which must be self signed.
420 =item B<-CAkey filename>
422 Sets the CA private key to sign a certificate with. If this option is
423 not specified then it is assumed that the CA private key is present in
424 the CA certificate file.
426 =item B<-CAserial filename>
428 Sets the CA serial number file to use.
430 When the B<-CA> option is used to sign a certificate it uses a serial
431 number specified in a file. This file consists of one line containing
432 an even number of hex digits with the serial number to use. After each
433 use the serial number is incremented and written out to the file again.
435 The default filename consists of the CA certificate file base name with
436 ".srl" appended. For example if the CA certificate file is called
437 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
439 =item B<-CAcreateserial>
441 With this option the CA serial number file is created if it does not exist:
442 it will contain the serial number "02" and the certificate being signed will
443 have the 1 as its serial number. If the B<-CA> option is specified
444 and the serial number file does not exist a random number is generated;
445 this is the recommended practice.
447 =item B<-extfile filename>
449 File containing certificate extensions to use. If not specified then
450 no extensions are added to the certificate.
452 =item B<-extensions section>
454 The section to add certificate extensions from. If this option is not
455 specified then the extensions should either be contained in the unnamed
456 (default) section or the default section should contain a variable called
457 "extensions" which contains the section to use. See the
458 L<x509v3_config(5)> manual page for details of the
459 extension section format.
461 =item B<-force_pubkey key>
463 When a certificate is created set its public key to B<key> instead of the
464 key in the certificate or certificate request. This option is useful for
465 creating certificates where the algorithm can't normally sign requests, for
468 The format or B<key> can be specified using the B<-keyform> option.
474 The B<nameopt> command line switch determines how the subject and issuer
475 names are displayed. If no B<nameopt> switch is present the default "oneline"
476 format is used which is compatible with previous versions of OpenSSL.
477 Each option is described in detail below, all options can be preceded by
478 a B<-> to turn the option off. Only the first four will normally be used.
488 Displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
489 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
490 B<sep_comma_plus>, B<dn_rev> and B<sname>.
494 A oneline format which is more readable than RFC2253. It is equivalent to
495 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
496 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
497 options. This is the I<default> of no name options are given explicitly.
501 A multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
502 B<space_eq>, B<lname> and B<align>.
506 Escape the "special" characters required by RFC2253 in a field. That is
507 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
508 and a space character at the beginning or end of a string.
512 Escape the "special" characters required by RFC2254 in a field. That is
513 the B<NUL> character as well as and B<()*>.
517 Escape control characters. That is those with ASCII values less than
518 0x20 (space) and the delete (0x7f) character. They are escaped using the
519 RFC2253 \XX notation (where XX are two hex digits representing the
524 Escape characters with the MSB set, that is with ASCII values larger than
529 Escapes some characters by surrounding the whole string with B<"> characters,
530 without the option all escaping is done with the B<\> character.
534 Convert all strings to UTF8 format first. This is required by RFC2253. If
535 you are lucky enough to have a UTF8 compatible terminal then the use
536 of this option (and B<not> setting B<esc_msb>) may result in the correct
537 display of multibyte (international) characters. Is this option is not
538 present then multibyte characters larger than 0xff will be represented
539 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
540 Also if this option is off any UTF8Strings will be converted to their
541 character form first.
545 This option does not attempt to interpret multibyte characters in any
546 way. That is their content octets are merely dumped as though one octet
547 represents each character. This is useful for diagnostic purposes but
548 will result in rather odd looking output.
552 Show the type of the ASN1 character string. The type precedes the
553 field contents. For example "BMPSTRING: Hello World".
557 When this option is set any fields that need to be hexdumped will
558 be dumped using the DER encoding of the field. Otherwise just the
559 content octets will be displayed. Both options use the RFC2253
564 Dump non character string types (for example OCTET STRING) if this
565 option is not set then non character string types will be displayed
566 as though each content octet represents a single character.
570 Dump all fields. This option when used with B<dump_der> allows the
571 DER encoding of the structure to be unambiguously determined.
573 =item B<dump_unknown>
575 Dump any field whose OID is not recognised by OpenSSL.
577 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
580 These options determine the field separators. The first character is
581 between RDNs and the second between multiple AVAs (multiple AVAs are
582 very rare and their use is discouraged). The options ending in
583 "space" additionally place a space after the separator to make it
584 more readable. The B<sep_multiline> uses a linefeed character for
585 the RDN separator and a spaced B<+> for the AVA separator. It also
586 indents the fields by four characters. If no field separator is specified
587 then B<sep_comma_plus_space> is used by default.
591 Reverse the fields of the DN. This is required by RFC2253. As a side
592 effect this also reverses the order of multiple AVAs but this is
595 =item B<nofname>, B<sname>, B<lname>, B<oid>
597 These options alter how the field name is displayed. B<nofname> does
598 not display the field at all. B<sname> uses the "short name" form
599 (CN for commonName for example). B<lname> uses the long form.
600 B<oid> represents the OID in numerical form and is useful for
605 Align field values for a more readable output. Only usable with
610 Places spaces round the B<=> character which follows the field
617 As well as customising the name output format, it is also possible to
618 customise the actual fields printed using the B<certopt> options when
619 the B<text> option is present. The default behaviour is to print all fields.
625 Use the old format. This is equivalent to specifying no output options at all.
629 Don't print header information: that is the lines saying "Certificate"
634 Don't print out the version number.
638 Don't print out the serial number.
642 Don't print out the signature algorithm used.
646 Don't print the validity, that is the B<notBefore> and B<notAfter> fields.
650 Don't print out the subject name.
654 Don't print out the issuer name.
658 Don't print out the public key.
662 Don't give a hexadecimal dump of the certificate signature.
666 Don't print out certificate trust information.
668 =item B<no_extensions>
670 Don't print out any X509V3 extensions.
674 Retain default extension behaviour: attempt to print out unsupported
675 certificate extensions.
679 Print an error message for unsupported certificate extensions.
683 ASN1 parse unsupported extensions.
687 Hex dump unsupported extensions.
691 The value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
692 B<no_header>, and B<no_version>.
698 Note: in these examples the '\' means the example should be all on one
701 Display the contents of a certificate:
703 openssl x509 -in cert.pem -noout -text
705 Display the "Subject Alternative Name" extension of a certificate:
707 openssl x509 -in cert.pem -noout -ext subjectAltName
709 Display more extensions of a certificate:
711 openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType
713 Display the certificate serial number:
715 openssl x509 -in cert.pem -noout -serial
717 Display the certificate subject name:
719 openssl x509 -in cert.pem -noout -subject
721 Display the certificate subject name in RFC2253 form:
723 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
725 Display the certificate subject name in oneline form on a terminal
728 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
730 Display the certificate SHA1 fingerprint:
732 openssl x509 -sha1 -in cert.pem -noout -fingerprint
734 Convert a certificate from PEM to DER format:
736 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
738 Convert a certificate to a certificate request:
740 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
742 Convert a certificate request into a self signed certificate using
745 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
746 -signkey key.pem -out cacert.pem
748 Sign a certificate request using the CA certificate above and add user
749 certificate extensions:
751 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
752 -CA cacert.pem -CAkey key.pem -CAcreateserial
755 Set a certificate to be trusted for SSL client use and change set its alias to
758 openssl x509 -in cert.pem -addtrust clientAuth \
759 -setalias "Steve's Class 1 CA" -out trust.pem
763 The PEM format uses the header and footer lines:
765 -----BEGIN CERTIFICATE-----
766 -----END CERTIFICATE-----
768 it will also handle files containing:
770 -----BEGIN X509 CERTIFICATE-----
771 -----END X509 CERTIFICATE-----
773 Trusted certificates have the lines
775 -----BEGIN TRUSTED CERTIFICATE-----
776 -----END TRUSTED CERTIFICATE-----
778 The conversion to UTF8 format used with the name options assumes that
779 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
780 and MSIE do this as do many certificates. So although this is incorrect
781 it is more likely to display the majority of certificates correctly.
783 The B<-email> option searches the subject name and the subject alternative
784 name extension. Only unique email addresses will be printed out: it will
785 not print the same address more than once.
787 =head1 CERTIFICATE EXTENSIONS
789 The B<-purpose> option checks the certificate extensions and determines
790 what the certificate can be used for. The actual checks done are rather
791 complex and include various hacks and workarounds to handle broken
792 certificates and software.
794 The same code is used when verifying untrusted certificates in chains
795 so this section is useful if a chain is rejected by the verify code.
797 The basicConstraints extension CA flag is used to determine whether the
798 certificate can be used as a CA. If the CA flag is true then it is a CA,
799 if the CA flag is false then it is not a CA. B<All> CAs should have the
802 If the basicConstraints extension is absent then the certificate is
803 considered to be a "possible CA" other extensions are checked according
804 to the intended use of the certificate. A warning is given in this case
805 because the certificate should really not be regarded as a CA: however
806 it is allowed to be a CA to work around some broken software.
808 If the certificate is a V1 certificate (and thus has no extensions) and
809 it is self signed it is also assumed to be a CA but a warning is again
810 given: this is to work around the problem of Verisign roots which are V1
811 self signed certificates.
813 If the keyUsage extension is present then additional restraints are
814 made on the uses of the certificate. A CA certificate B<must> have the
815 keyCertSign bit set if the keyUsage extension is present.
817 The extended key usage extension places additional restrictions on the
818 certificate uses. If this extension is present (whether critical or not)
819 the key can only be used for the purposes specified.
821 A complete description of each test is given below. The comments about
822 basicConstraints and keyUsage and V1 certificates above apply to B<all>
830 The extended key usage extension must be absent or include the "web client
831 authentication" OID. keyUsage must be absent or it must have the
832 digitalSignature bit set. Netscape certificate type must be absent or it must
833 have the SSL client bit set.
835 =item B<SSL Client CA>
837 The extended key usage extension must be absent or include the "web client
838 authentication" OID. Netscape certificate type must be absent or it must have
839 the SSL CA bit set: this is used as a work around if the basicConstraints
844 The extended key usage extension must be absent or include the "web server
845 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
846 must have the digitalSignature, the keyEncipherment set or both bits set.
847 Netscape certificate type must be absent or have the SSL server bit set.
849 =item B<SSL Server CA>
851 The extended key usage extension must be absent or include the "web server
852 authentication" and/or one of the SGC OIDs. Netscape certificate type must
853 be absent or the SSL CA bit must be set: this is used as a work around if the
854 basicConstraints extension is absent.
856 =item B<Netscape SSL Server>
858 For Netscape SSL clients to connect to an SSL server it must have the
859 keyEncipherment bit set if the keyUsage extension is present. This isn't
860 always valid because some cipher suites use the key for digital signing.
861 Otherwise it is the same as a normal SSL server.
863 =item B<Common S/MIME Client Tests>
865 The extended key usage extension must be absent or include the "email
866 protection" OID. Netscape certificate type must be absent or should have the
867 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
868 then the SSL client bit is tolerated as an alternative but a warning is shown:
869 this is because some Verisign certificates don't set the S/MIME bit.
871 =item B<S/MIME Signing>
873 In addition to the common S/MIME client tests the digitalSignature bit or
874 the nonRepudiation bit must be set if the keyUsage extension is present.
876 =item B<S/MIME Encryption>
878 In addition to the common S/MIME tests the keyEncipherment bit must be set
879 if the keyUsage extension is present.
883 The extended key usage extension must be absent or include the "email
884 protection" OID. Netscape certificate type must be absent or must have the
885 S/MIME CA bit set: this is used as a work around if the basicConstraints
890 The keyUsage extension must be absent or it must have the CRL signing bit
893 =item B<CRL Signing CA>
895 The normal CA tests apply. Except in this case the basicConstraints extension
902 Extensions in certificates are not transferred to certificate requests and
905 It is possible to produce invalid certificates or requests by specifying the
906 wrong private key or using inconsistent options in some cases: these should
909 There should be options to explicitly set such things as start and end
910 dates rather than an offset from the current time.
914 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
915 L<gendsa(1)>, L<verify(1)>,
920 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
921 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
922 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
923 canonical version of the DN using SHA1. This means that any directories using
924 the old form must have their links rebuilt using B<c_rehash> or similar.
928 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
930 Licensed under the OpenSSL license (the "License"). You may not use
931 this file except in compliance with the License. You can obtain a copy
932 in the file LICENSE in the source distribution or at
933 L<https://www.openssl.org/source/license.html>.