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>]
61 [B<-extfile filename>]
62 [B<-extensions section>]
70 The B<x509> command is a multi purpose certificate utility. It can be
71 used to display certificate information, convert certificates to
72 various forms, sign certificate requests like a "mini CA" or edit
73 certificate trust settings.
75 Since there are a large number of options they will split up into
80 =head2 Input, Output, and General Purpose Options
86 Print out a usage message.
88 =item B<-inform DER|PEM|NET>
90 This specifies the input format normally the command will expect an X509
91 certificate but this can change if other options such as B<-req> are
92 present. The DER format is the DER encoding of the certificate and PEM
93 is the base64 encoding of the DER encoding with header and footer lines
94 added. The NET option is an obscure Netscape server format that is now
95 obsolete. The default format is PEM.
97 =item B<-outform DER|PEM|NET>
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 request.
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 Prints out the digest of the DER encoded version of the whole certificate
262 (see digest options).
266 This outputs the certificate in the form of a C source file.
270 =head2 Trust Settings
272 A B<trusted certificate> is an ordinary certificate which has several
273 additional pieces of information attached to it such as the permitted
274 and prohibited uses of the certificate and an "alias".
276 Normally when a certificate is being verified at least one certificate
277 must be "trusted". By default a trusted certificate must be stored
278 locally and must be a root CA: any certificate chain ending in this CA
279 is then usable for any purpose.
281 Trust settings currently are only used with a root CA. They allow a finer
282 control over the purposes the root CA can be used for. For example a CA
283 may be trusted for SSL client but not SSL server use.
285 See the description of the B<verify> utility for more information on the
286 meaning of trust settings.
288 Future versions of OpenSSL will recognize trust settings on any
289 certificate: not just root CAs.
296 This causes B<x509> to output a B<trusted> certificate. An ordinary
297 or trusted certificate can be input but by default an ordinary
298 certificate is output and any trust settings are discarded. With the
299 B<-trustout> option a trusted certificate is output. A trusted
300 certificate is automatically output if any trust settings are modified.
302 =item B<-setalias arg>
304 Sets the alias of the certificate. This will allow the certificate
305 to be referred to using a nickname for example "Steve's Certificate".
309 Outputs the certificate alias, if any.
313 Clears all the permitted or trusted uses of the certificate.
317 Clears all the prohibited or rejected uses of the certificate.
319 =item B<-addtrust arg>
321 Adds a trusted certificate use.
322 Any object name can be used here but currently only B<clientAuth> (SSL client
323 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
324 B<anyExtendedKeyUsage> are used.
325 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
326 enables all purposes when trusted.
327 Other OpenSSL applications may define additional uses.
329 =item B<-addreject arg>
331 Adds a prohibited use. It accepts the same values as the B<-addtrust>
336 This option performs tests on the certificate extensions and outputs
337 the results. For a more complete description see the B<CERTIFICATE
342 =head2 Signing Options
344 The B<x509> utility can be used to sign certificates and requests: it
345 can thus behave like a "mini CA".
349 =item B<-signkey filename>
351 This option causes the input file to be self signed using the supplied
354 If the input file is a certificate it sets the issuer name to the
355 subject name (i.e. makes it self signed) changes the public key to the
356 supplied value and changes the start and end dates. The start date is
357 set to the current time and the end date is set to a value determined
358 by the B<-days> option. Any certificate extensions are retained unless
359 the B<-clrext> option is supplied; this includes, for example, any existing
360 key identifier extensions.
362 If the input is a certificate request then a self signed certificate
363 is created using the supplied private key using the subject name in
368 The key password source. For more information about the format of B<arg>
369 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
373 Delete any extensions from a certificate. This option is used when a
374 certificate is being created from another certificate (for example with
375 the B<-signkey> or the B<-CA> options). Normally all extensions are
378 =item B<-keyform PEM|DER>
380 Specifies the format (DER or PEM) of the private key file used in the
385 Specifies the number of days to make a certificate valid for. The default
386 is 30 days. Cannot be used with the B<-preserve_dates> option.
390 Converts a certificate into a certificate request. The B<-signkey> option
391 is used to pass the required private key.
395 By default a certificate is expected on input. With this option a
396 certificate request is expected instead.
398 =item B<-set_serial n>
400 Specifies the serial number to use. This option can be used with either
401 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
402 option the serial number file (as specified by the B<-CAserial> or
403 B<-CAcreateserial> options) is not used.
405 The serial number can be decimal or hex (if preceded by B<0x>).
407 =item B<-CA filename>
409 Specifies the CA certificate to be used for signing. When this option is
410 present B<x509> behaves like a "mini CA". The input file is signed by this
411 CA using this option: that is its issuer name is set to the subject name
412 of the CA and it is digitally signed using the CAs private key.
414 This option is normally combined with the B<-req> option. Without the
415 B<-req> option the input is a certificate which must be self signed.
417 =item B<-CAkey filename>
419 Sets the CA private key to sign a certificate with. If this option is
420 not specified then it is assumed that the CA private key is present in
421 the CA certificate file.
423 =item B<-CAserial filename>
425 Sets the CA serial number file to use.
427 When the B<-CA> option is used to sign a certificate it uses a serial
428 number specified in a file. This file consist of one line containing
429 an even number of hex digits with the serial number to use. After each
430 use the serial number is incremented and written out to the file again.
432 The default filename consists of the CA certificate file base name with
433 ".srl" appended. For example if the CA certificate file is called
434 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
436 =item B<-CAcreateserial>
438 With this option the CA serial number file is created if it does not exist:
439 it will contain the serial number "02" and the certificate being signed will
440 have the 1 as its serial number. If the B<-CA> option is specified
441 and the serial number file does not exist a random number is generated;
442 this is the recommended practice.
444 =item B<-extfile filename>
446 File containing certificate extensions to use. If not specified then
447 no extensions are added to the certificate.
449 =item B<-extensions section>
451 The section to add certificate extensions from. If this option is not
452 specified then the extensions should either be contained in the unnamed
453 (default) section or the default section should contain a variable called
454 "extensions" which contains the section to use. See the
455 L<x509v3_config(5)> manual page for details of the
456 extension section format.
458 =item B<-force_pubkey key>
460 When a certificate is created set its public key to B<key> instead of the
461 key in the certificate or certificate request. This option is useful for
462 creating certificates where the algorithm can't normally sign requests, for
465 The format or B<key> can be specified using the B<-keyform> option.
471 The B<nameopt> command line switch determines how the subject and issuer
472 names are displayed. If no B<nameopt> switch is present the default "oneline"
473 format is used which is compatible with previous versions of OpenSSL.
474 Each option is described in detail below, all options can be preceded by
475 a B<-> to turn the option off. Only the first four will normally be used.
485 Displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
486 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
487 B<sep_comma_plus>, B<dn_rev> and B<sname>.
491 A oneline format which is more readable than RFC2253. It is equivalent to
492 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
493 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
494 options. This is the I<default> of no name options are given explicitly.
498 A multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
499 B<space_eq>, B<lname> and B<align>.
503 Escape the "special" characters required by RFC2253 in a field. That is
504 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
505 and a space character at the beginning or end of a string.
509 Escape the "special" characters required by RFC2254 in a field. That is
510 the B<NUL> character as well as and B<()*>.
514 Escape control characters. That is those with ASCII values less than
515 0x20 (space) and the delete (0x7f) character. They are escaped using the
516 RFC2253 \XX notation (where XX are two hex digits representing the
521 Escape characters with the MSB set, that is with ASCII values larger than
526 Escapes some characters by surrounding the whole string with B<"> characters,
527 without the option all escaping is done with the B<\> character.
531 Convert all strings to UTF8 format first. This is required by RFC2253. If
532 you are lucky enough to have a UTF8 compatible terminal then the use
533 of this option (and B<not> setting B<esc_msb>) may result in the correct
534 display of multibyte (international) characters. Is this option is not
535 present then multibyte characters larger than 0xff will be represented
536 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
537 Also if this option is off any UTF8Strings will be converted to their
538 character form first.
542 This option does not attempt to interpret multibyte characters in any
543 way. That is their content octets are merely dumped as though one octet
544 represents each character. This is useful for diagnostic purposes but
545 will result in rather odd looking output.
549 Show the type of the ASN1 character string. The type precedes the
550 field contents. For example "BMPSTRING: Hello World".
554 When this option is set any fields that need to be hexdumped will
555 be dumped using the DER encoding of the field. Otherwise just the
556 content octets will be displayed. Both options use the RFC2253
561 Dump non character string types (for example OCTET STRING) if this
562 option is not set then non character string types will be displayed
563 as though each content octet represents a single character.
567 Dump all fields. This option when used with B<dump_der> allows the
568 DER encoding of the structure to be unambiguously determined.
570 =item B<dump_unknown>
572 Dump any field whose OID is not recognised by OpenSSL.
574 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
577 These options determine the field separators. The first character is
578 between RDNs and the second between multiple AVAs (multiple AVAs are
579 very rare and their use is discouraged). The options ending in
580 "space" additionally place a space after the separator to make it
581 more readable. The B<sep_multiline> uses a linefeed character for
582 the RDN separator and a spaced B<+> for the AVA separator. It also
583 indents the fields by four characters. If no field separator is specified
584 then B<sep_comma_plus_space> is used by default.
588 Reverse the fields of the DN. This is required by RFC2253. As a side
589 effect this also reverses the order of multiple AVAs but this is
592 =item B<nofname>, B<sname>, B<lname>, B<oid>
594 These options alter how the field name is displayed. B<nofname> does
595 not display the field at all. B<sname> uses the "short name" form
596 (CN for commonName for example). B<lname> uses the long form.
597 B<oid> represents the OID in numerical form and is useful for
602 Align field values for a more readable output. Only usable with
607 Places spaces round the B<=> character which follows the field
614 As well as customising the name output format, it is also possible to
615 customise the actual fields printed using the B<certopt> options when
616 the B<text> option is present. The default behaviour is to print all fields.
622 Use the old format. This is equivalent to specifying no output options at all.
626 Don't print header information: that is the lines saying "Certificate"
631 Don't print out the version number.
635 Don't print out the serial number.
639 Don't print out the signature algorithm used.
643 Don't print the validity, that is the B<notBefore> and B<notAfter> fields.
647 Don't print out the subject name.
651 Don't print out the issuer name.
655 Don't print out the public key.
659 Don't give a hexadecimal dump of the certificate signature.
663 Don't print out certificate trust information.
665 =item B<no_extensions>
667 Don't print out any X509V3 extensions.
671 Retain default extension behaviour: attempt to print out unsupported
672 certificate extensions.
676 Print an error message for unsupported certificate extensions.
680 ASN1 parse unsupported extensions.
684 Hex dump unsupported extensions.
688 The value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
689 B<no_header>, and B<no_version>.
695 Note: in these examples the '\' means the example should be all on one
698 Display the contents of a certificate:
700 openssl x509 -in cert.pem -noout -text
702 Display the "Subject Alternative Name" extension of a certificate:
704 openssl x509 -in cert.pem -noout -ext subjectAltName
706 Display more extensions of a certificate:
708 openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType
710 Display the certificate serial number:
712 openssl x509 -in cert.pem -noout -serial
714 Display the certificate subject name:
716 openssl x509 -in cert.pem -noout -subject
718 Display the certificate subject name in RFC2253 form:
720 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
722 Display the certificate subject name in oneline form on a terminal
725 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
727 Display the certificate MD5 fingerprint:
729 openssl x509 -in cert.pem -noout -fingerprint
731 Display the certificate SHA1 fingerprint:
733 openssl x509 -sha1 -in cert.pem -noout -fingerprint
735 Convert a certificate from PEM to DER format:
737 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
739 Convert a certificate to a certificate request:
741 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
743 Convert a certificate request into a self signed certificate using
746 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
747 -signkey key.pem -out cacert.pem
749 Sign a certificate request using the CA certificate above and add user
750 certificate extensions:
752 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
753 -CA cacert.pem -CAkey key.pem -CAcreateserial
756 Set a certificate to be trusted for SSL client use and change set its alias to
759 openssl x509 -in cert.pem -addtrust clientAuth \
760 -setalias "Steve's Class 1 CA" -out trust.pem
764 The PEM format uses the header and footer lines:
766 -----BEGIN CERTIFICATE-----
767 -----END CERTIFICATE-----
769 it will also handle files containing:
771 -----BEGIN X509 CERTIFICATE-----
772 -----END X509 CERTIFICATE-----
774 Trusted certificates have the lines
776 -----BEGIN TRUSTED CERTIFICATE-----
777 -----END TRUSTED CERTIFICATE-----
779 The conversion to UTF8 format used with the name options assumes that
780 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
781 and MSIE do this as do many certificates. So although this is incorrect
782 it is more likely to display the majority of certificates correctly.
784 The B<-fingerprint> option takes the digest of the DER encoded certificate.
785 This is commonly called a "fingerprint". Because of the nature of message
786 digests the fingerprint of a certificate is unique to that certificate and
787 two certificates with the same fingerprint can be considered to be the same.
789 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
791 The B<-email> option searches the subject name and the subject alternative
792 name extension. Only unique email addresses will be printed out: it will
793 not print the same address more than once.
795 =head1 CERTIFICATE EXTENSIONS
797 The B<-purpose> option checks the certificate extensions and determines
798 what the certificate can be used for. The actual checks done are rather
799 complex and include various hacks and workarounds to handle broken
800 certificates and software.
802 The same code is used when verifying untrusted certificates in chains
803 so this section is useful if a chain is rejected by the verify code.
805 The basicConstraints extension CA flag is used to determine whether the
806 certificate can be used as a CA. If the CA flag is true then it is a CA,
807 if the CA flag is false then it is not a CA. B<All> CAs should have the
810 If the basicConstraints extension is absent then the certificate is
811 considered to be a "possible CA" other extensions are checked according
812 to the intended use of the certificate. A warning is given in this case
813 because the certificate should really not be regarded as a CA: however
814 it is allowed to be a CA to work around some broken software.
816 If the certificate is a V1 certificate (and thus has no extensions) and
817 it is self signed it is also assumed to be a CA but a warning is again
818 given: this is to work around the problem of Verisign roots which are V1
819 self signed certificates.
821 If the keyUsage extension is present then additional restraints are
822 made on the uses of the certificate. A CA certificate B<must> have the
823 keyCertSign bit set if the keyUsage extension is present.
825 The extended key usage extension places additional restrictions on the
826 certificate uses. If this extension is present (whether critical or not)
827 the key can only be used for the purposes specified.
829 A complete description of each test is given below. The comments about
830 basicConstraints and keyUsage and V1 certificates above apply to B<all>
838 The extended key usage extension must be absent or include the "web client
839 authentication" OID. keyUsage must be absent or it must have the
840 digitalSignature bit set. Netscape certificate type must be absent or it must
841 have the SSL client bit set.
843 =item B<SSL Client CA>
845 The extended key usage extension must be absent or include the "web client
846 authentication" OID. Netscape certificate type must be absent or it must have
847 the SSL CA bit set: this is used as a work around if the basicConstraints
852 The extended key usage extension must be absent or include the "web server
853 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
854 must have the digitalSignature, the keyEncipherment set or both bits set.
855 Netscape certificate type must be absent or have the SSL server bit set.
857 =item B<SSL Server CA>
859 The extended key usage extension must be absent or include the "web server
860 authentication" and/or one of the SGC OIDs. Netscape certificate type must
861 be absent or the SSL CA bit must be set: this is used as a work around if the
862 basicConstraints extension is absent.
864 =item B<Netscape SSL Server>
866 For Netscape SSL clients to connect to an SSL server it must have the
867 keyEncipherment bit set if the keyUsage extension is present. This isn't
868 always valid because some cipher suites use the key for digital signing.
869 Otherwise it is the same as a normal SSL server.
871 =item B<Common S/MIME Client Tests>
873 The extended key usage extension must be absent or include the "email
874 protection" OID. Netscape certificate type must be absent or should have the
875 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
876 then the SSL client bit is tolerated as an alternative but a warning is shown:
877 this is because some Verisign certificates don't set the S/MIME bit.
879 =item B<S/MIME Signing>
881 In addition to the common S/MIME client tests the digitalSignature bit must
882 be set if the keyUsage extension is present.
884 =item B<S/MIME Encryption>
886 In addition to the common S/MIME tests the keyEncipherment bit must be set
887 if the keyUsage extension is present.
891 The extended key usage extension must be absent or include the "email
892 protection" OID. Netscape certificate type must be absent or must have the
893 S/MIME CA bit set: this is used as a work around if the basicConstraints
898 The keyUsage extension must be absent or it must have the CRL signing bit
901 =item B<CRL Signing CA>
903 The normal CA tests apply. Except in this case the basicConstraints extension
910 Extensions in certificates are not transferred to certificate requests and
913 It is possible to produce invalid certificates or requests by specifying the
914 wrong private key or using inconsistent options in some cases: these should
917 There should be options to explicitly set such things as start and end
918 dates rather than an offset from the current time.
922 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
923 L<gendsa(1)>, L<verify(1)>,
928 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
929 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
930 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
931 canonical version of the DN using SHA1. This means that any directories using
932 the old form must have their links rebuilt using B<c_rehash> or similar.
936 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
938 Licensed under the OpenSSL license (the "License"). You may not use
939 this file except in compliance with the License. You can obtain a copy
940 in the file LICENSE in the source distribution or at
941 L<https://www.openssl.org/source/license.html>.