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>]
67 The B<x509> command is a multi purpose certificate utility. It can be
68 used to display certificate information, convert certificates to
69 various forms, sign certificate requests like a "mini CA" or edit
70 certificate trust settings.
72 Since there are a large number of options they will split up into
77 =head2 Input, Output, and General Purpose Options
83 Print out a usage message.
85 =item B<-inform DER|PEM|NET>
87 This specifies the input format normally the command will expect an X509
88 certificate but this can change if other options such as B<-req> are
89 present. The DER format is the DER encoding of the certificate and PEM
90 is the base64 encoding of the DER encoding with header and footer lines
91 added. The NET option is an obscure Netscape server format that is now
94 =item B<-outform DER|PEM|NET>
96 This specifies the output format, the options have the same meaning as the
101 This specifies the input filename to read a certificate from or standard input
102 if this option is not specified.
104 =item B<-out filename>
106 This specifies the output filename to write to or standard output by
112 This affects any signing or display option that uses a message
113 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options.
114 Any digest supported by the OpenSSL B<dgst> command can be used.
115 If not specified then SHA1 is used with B<-fingerprint> or
116 the default digest for the signing algorithm is used, typically SHA256.
120 Specifying an engine (by its unique B<id> string) will cause B<x509>
121 to attempt to obtain a functional reference to the specified engine,
122 thus initialising it if needed. The engine will then be set as the default
123 for all available algorithms.
125 =item B<-preserve_dates>
127 When signing a certificate, preserve the "notBefore" and "notAfter" dates instead
128 of adjusting them to current time and duration. Cannot be used with the B<-days> option.
132 =head2 Display Options
134 Note: the B<-alias> and B<-purpose> options are also display options
135 but are described in the B<TRUST SETTINGS> section.
141 Prints out the certificate in text form. Full details are output including the
142 public key, signature algorithms, issuer and subject names, serial number
143 any extensions present and any trust settings.
145 =item B<-certopt option>
147 Customise the output format used with B<-text>. The B<option> argument
148 can be a single option or multiple options separated by commas. The
149 B<-certopt> switch may be also be used more than once to set multiple
150 options. See the B<TEXT OPTIONS> section for more information.
154 This option prevents output of the encoded version of the request.
158 Outputs the certificate's SubjectPublicKeyInfo block in PEM format.
162 This option prints out the value of the modulus of the public key
163 contained in the certificate.
167 Outputs the certificate serial number.
169 =item B<-subject_hash>
171 Outputs the "hash" of the certificate subject name. This is used in OpenSSL to
172 form an index to allow certificates in a directory to be looked up by subject
175 =item B<-issuer_hash>
177 Outputs the "hash" of the certificate issuer name.
181 Outputs the OCSP hash values for the subject name and public key.
185 Synonym for "-subject_hash" for backward compatibility reasons.
187 =item B<-subject_hash_old>
189 Outputs the "hash" of the certificate subject name using the older algorithm
190 as used by OpenSSL versions before 1.0.0.
192 =item B<-issuer_hash_old>
194 Outputs the "hash" of the certificate issuer name using the older algorithm
195 as used by OpenSSL versions before 1.0.0.
199 Outputs the subject name.
203 Outputs the issuer name.
205 =item B<-nameopt option>
207 Option which determines how the subject or issuer names are displayed. The
208 B<option> argument can be a single option or multiple options separated by
209 commas. Alternatively the B<-nameopt> switch may be used more than once to
210 set multiple options. See the B<NAME OPTIONS> section for more information.
214 Outputs the email address(es) if any.
218 Outputs the OCSP responder address(es) if any.
222 Prints out the start date of the certificate, that is the notBefore date.
226 Prints out the expiry date of the certificate, that is the notAfter date.
230 Prints out the start and expiry dates of a certificate.
232 =item B<-checkend arg>
234 Checks if the certificate expires within the next B<arg> seconds and exits
235 non-zero if yes it will expire or zero if not.
237 =item B<-fingerprint>
239 Prints out the digest of the DER encoded version of the whole certificate
240 (see digest options).
244 This outputs the certificate in the form of a C source file.
248 =head2 Trust Settings
250 A B<trusted certificate> is an ordinary certificate which has several
251 additional pieces of information attached to it such as the permitted
252 and prohibited uses of the certificate and an "alias".
254 Normally when a certificate is being verified at least one certificate
255 must be "trusted". By default a trusted certificate must be stored
256 locally and must be a root CA: any certificate chain ending in this CA
257 is then usable for any purpose.
259 Trust settings currently are only used with a root CA. They allow a finer
260 control over the purposes the root CA can be used for. For example a CA
261 may be trusted for SSL client but not SSL server use.
263 See the description of the B<verify> utility for more information on the
264 meaning of trust settings.
266 Future versions of OpenSSL will recognize trust settings on any
267 certificate: not just root CAs.
274 This causes B<x509> to output a B<trusted> certificate. An ordinary
275 or trusted certificate can be input but by default an ordinary
276 certificate is output and any trust settings are discarded. With the
277 B<-trustout> option a trusted certificate is output. A trusted
278 certificate is automatically output if any trust settings are modified.
280 =item B<-setalias arg>
282 Sets the alias of the certificate. This will allow the certificate
283 to be referred to using a nickname for example "Steve's Certificate".
287 Outputs the certificate alias, if any.
291 Clears all the permitted or trusted uses of the certificate.
295 Clears all the prohibited or rejected uses of the certificate.
297 =item B<-addtrust arg>
299 Adds a trusted certificate use.
300 Any object name can be used here but currently only B<clientAuth> (SSL client
301 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
302 B<anyExtendedKeyUsage> are used.
303 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
304 enables all purposes when trusted.
305 Other OpenSSL applications may define additional uses.
307 =item B<-addreject arg>
309 Adds a prohibited use. It accepts the same values as the B<-addtrust>
314 This option performs tests on the certificate extensions and outputs
315 the results. For a more complete description see the B<CERTIFICATE
320 =head2 Signing Options
322 The B<x509> utility can be used to sign certificates and requests: it
323 can thus behave like a "mini CA".
327 =item B<-signkey filename>
329 This option causes the input file to be self signed using the supplied
332 If the input file is a certificate it sets the issuer name to the
333 subject name (i.e. makes it self signed) changes the public key to the
334 supplied value and changes the start and end dates. The start date is
335 set to the current time and the end date is set to a value determined
336 by the B<-days> option. Any certificate extensions are retained unless
337 the B<-clrext> option is supplied; this includes, for example, any existing
338 key identifier extensions.
340 If the input is a certificate request then a self signed certificate
341 is created using the supplied private key using the subject name in
346 The key password source. For more information about the format of B<arg>
347 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
351 Delete any extensions from a certificate. This option is used when a
352 certificate is being created from another certificate (for example with
353 the B<-signkey> or the B<-CA> options). Normally all extensions are
356 =item B<-keyform PEM|DER>
358 Specifies the format (DER or PEM) of the private key file used in the
363 Specifies the number of days to make a certificate valid for. The default
364 is 30 days. Cannot be used with the B<-preserve_dates> option.
368 Converts a certificate into a certificate request. The B<-signkey> option
369 is used to pass the required private key.
373 By default a certificate is expected on input. With this option a
374 certificate request is expected instead.
376 =item B<-set_serial n>
378 Specifies the serial number to use. This option can be used with either
379 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
380 option the serial number file (as specified by the B<-CAserial> or
381 B<-CAcreateserial> options) is not used.
383 The serial number can be decimal or hex (if preceded by B<0x>).
385 =item B<-CA filename>
387 Specifies the CA certificate to be used for signing. When this option is
388 present B<x509> behaves like a "mini CA". The input file is signed by this
389 CA using this option: that is its issuer name is set to the subject name
390 of the CA and it is digitally signed using the CAs private key.
392 This option is normally combined with the B<-req> option. Without the
393 B<-req> option the input is a certificate which must be self signed.
395 =item B<-CAkey filename>
397 Sets the CA private key to sign a certificate with. If this option is
398 not specified then it is assumed that the CA private key is present in
399 the CA certificate file.
401 =item B<-CAserial filename>
403 Sets the CA serial number file to use.
405 When the B<-CA> option is used to sign a certificate it uses a serial
406 number specified in a file. This file consist of one line containing
407 an even number of hex digits with the serial number to use. After each
408 use the serial number is incremented and written out to the file again.
410 The default filename consists of the CA certificate file base name with
411 ".srl" appended. For example if the CA certificate file is called
412 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
414 =item B<-CAcreateserial>
416 With this option the CA serial number file is created if it does not exist:
417 it will contain the serial number "02" and the certificate being signed will
418 have the 1 as its serial number. If the B<-CA> option is specified
419 and the serial number file does not exist a random number is generated;
420 this is the recommended practice.
422 =item B<-extfile filename>
424 File containing certificate extensions to use. If not specified then
425 no extensions are added to the certificate.
427 =item B<-extensions section>
429 The section to add certificate extensions from. If this option is not
430 specified then the extensions should either be contained in the unnamed
431 (default) section or the default section should contain a variable called
432 "extensions" which contains the section to use. See the
433 L<x509v3_config(5)> manual page for details of the
434 extension section format.
436 =item B<-force_pubkey key>
438 When a certificate is created set its public key to B<key> instead of the
439 key in the certificate or certificate request. This option is useful for
440 creating certificates where the algorithm can't normally sign requests, for
443 The format or B<key> can be specified using the B<-keyform> option.
449 The B<nameopt> command line switch determines how the subject and issuer
450 names are displayed. If no B<nameopt> switch is present the default "oneline"
451 format is used which is compatible with previous versions of OpenSSL.
452 Each option is described in detail below, all options can be preceded by
453 a B<-> to turn the option off. Only the first four will normally be used.
463 Displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
464 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
465 B<sep_comma_plus>, B<dn_rev> and B<sname>.
469 A oneline format which is more readable than RFC2253. It is equivalent to
470 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
471 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
472 options. This is the I<default> of no name options are given explicitly.
476 A multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
477 B<space_eq>, B<lname> and B<align>.
481 Escape the "special" characters required by RFC2253 in a field. That is
482 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
483 and a space character at the beginning or end of a string.
487 Escape the "special" characters required by RFC2254 in a field. That is
488 the B<NUL> character as well as and B<()*>.
492 Escape control characters. That is those with ASCII values less than
493 0x20 (space) and the delete (0x7f) character. They are escaped using the
494 RFC2253 \XX notation (where XX are two hex digits representing the
499 Escape characters with the MSB set, that is with ASCII values larger than
504 Escapes some characters by surrounding the whole string with B<"> characters,
505 without the option all escaping is done with the B<\> character.
509 Convert all strings to UTF8 format first. This is required by RFC2253. If
510 you are lucky enough to have a UTF8 compatible terminal then the use
511 of this option (and B<not> setting B<esc_msb>) may result in the correct
512 display of multibyte (international) characters. Is this option is not
513 present then multibyte characters larger than 0xff will be represented
514 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
515 Also if this option is off any UTF8Strings will be converted to their
516 character form first.
520 This option does not attempt to interpret multibyte characters in any
521 way. That is their content octets are merely dumped as though one octet
522 represents each character. This is useful for diagnostic purposes but
523 will result in rather odd looking output.
527 Show the type of the ASN1 character string. The type precedes the
528 field contents. For example "BMPSTRING: Hello World".
532 When this option is set any fields that need to be hexdumped will
533 be dumped using the DER encoding of the field. Otherwise just the
534 content octets will be displayed. Both options use the RFC2253
539 Dump non character string types (for example OCTET STRING) if this
540 option is not set then non character string types will be displayed
541 as though each content octet represents a single character.
545 Dump all fields. This option when used with B<dump_der> allows the
546 DER encoding of the structure to be unambiguously determined.
548 =item B<dump_unknown>
550 Dump any field whose OID is not recognised by OpenSSL.
552 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
555 These options determine the field separators. The first character is
556 between RDNs and the second between multiple AVAs (multiple AVAs are
557 very rare and their use is discouraged). The options ending in
558 "space" additionally place a space after the separator to make it
559 more readable. The B<sep_multiline> uses a linefeed character for
560 the RDN separator and a spaced B<+> for the AVA separator. It also
561 indents the fields by four characters. If no field separator is specified
562 then B<sep_comma_plus_space> is used by default.
566 Reverse the fields of the DN. This is required by RFC2253. As a side
567 effect this also reverses the order of multiple AVAs but this is
570 =item B<nofname>, B<sname>, B<lname>, B<oid>
572 These options alter how the field name is displayed. B<nofname> does
573 not display the field at all. B<sname> uses the "short name" form
574 (CN for commonName for example). B<lname> uses the long form.
575 B<oid> represents the OID in numerical form and is useful for
580 Align field values for a more readable output. Only usable with
585 Places spaces round the B<=> character which follows the field
592 As well as customising the name output format, it is also possible to
593 customise the actual fields printed using the B<certopt> options when
594 the B<text> option is present. The default behaviour is to print all fields.
600 Use the old format. This is equivalent to specifying no output options at all.
604 Don't print header information: that is the lines saying "Certificate"
609 Don't print out the version number.
613 Don't print out the serial number.
617 Don't print out the signature algorithm used.
621 Don't print the validity, that is the B<notBefore> and B<notAfter> fields.
625 Don't print out the subject name.
629 Don't print out the issuer name.
633 Don't print out the public key.
637 Don't give a hexadecimal dump of the certificate signature.
641 Don't print out certificate trust information.
643 =item B<no_extensions>
645 Don't print out any X509V3 extensions.
649 Retain default extension behaviour: attempt to print out unsupported
650 certificate extensions.
654 Print an error message for unsupported certificate extensions.
658 ASN1 parse unsupported extensions.
662 Hex dump unsupported extensions.
666 The value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
667 B<no_header>, and B<no_version>.
673 Note: in these examples the '\' means the example should be all on one
676 Display the contents of a certificate:
678 openssl x509 -in cert.pem -noout -text
680 Display the certificate serial number:
682 openssl x509 -in cert.pem -noout -serial
684 Display the certificate subject name:
686 openssl x509 -in cert.pem -noout -subject
688 Display the certificate subject name in RFC2253 form:
690 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
692 Display the certificate subject name in oneline form on a terminal
695 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
697 Display the certificate MD5 fingerprint:
699 openssl x509 -in cert.pem -noout -fingerprint
701 Display the certificate SHA1 fingerprint:
703 openssl x509 -sha1 -in cert.pem -noout -fingerprint
705 Convert a certificate from PEM to DER format:
707 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
709 Convert a certificate to a certificate request:
711 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
713 Convert a certificate request into a self signed certificate using
716 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
717 -signkey key.pem -out cacert.pem
719 Sign a certificate request using the CA certificate above and add user
720 certificate extensions:
722 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
723 -CA cacert.pem -CAkey key.pem -CAcreateserial
726 Set a certificate to be trusted for SSL client use and change set its alias to
729 openssl x509 -in cert.pem -addtrust clientAuth \
730 -setalias "Steve's Class 1 CA" -out trust.pem
734 The PEM format uses the header and footer lines:
736 -----BEGIN CERTIFICATE-----
737 -----END CERTIFICATE-----
739 it will also handle files containing:
741 -----BEGIN X509 CERTIFICATE-----
742 -----END X509 CERTIFICATE-----
744 Trusted certificates have the lines
746 -----BEGIN TRUSTED CERTIFICATE-----
747 -----END TRUSTED CERTIFICATE-----
749 The conversion to UTF8 format used with the name options assumes that
750 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
751 and MSIE do this as do many certificates. So although this is incorrect
752 it is more likely to display the majority of certificates correctly.
754 The B<-fingerprint> option takes the digest of the DER encoded certificate.
755 This is commonly called a "fingerprint". Because of the nature of message
756 digests the fingerprint of a certificate is unique to that certificate and
757 two certificates with the same fingerprint can be considered to be the same.
759 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
761 The B<-email> option searches the subject name and the subject alternative
762 name extension. Only unique email addresses will be printed out: it will
763 not print the same address more than once.
765 =head1 CERTIFICATE EXTENSIONS
767 The B<-purpose> option checks the certificate extensions and determines
768 what the certificate can be used for. The actual checks done are rather
769 complex and include various hacks and workarounds to handle broken
770 certificates and software.
772 The same code is used when verifying untrusted certificates in chains
773 so this section is useful if a chain is rejected by the verify code.
775 The basicConstraints extension CA flag is used to determine whether the
776 certificate can be used as a CA. If the CA flag is true then it is a CA,
777 if the CA flag is false then it is not a CA. B<All> CAs should have the
780 If the basicConstraints extension is absent then the certificate is
781 considered to be a "possible CA" other extensions are checked according
782 to the intended use of the certificate. A warning is given in this case
783 because the certificate should really not be regarded as a CA: however
784 it is allowed to be a CA to work around some broken software.
786 If the certificate is a V1 certificate (and thus has no extensions) and
787 it is self signed it is also assumed to be a CA but a warning is again
788 given: this is to work around the problem of Verisign roots which are V1
789 self signed certificates.
791 If the keyUsage extension is present then additional restraints are
792 made on the uses of the certificate. A CA certificate B<must> have the
793 keyCertSign bit set if the keyUsage extension is present.
795 The extended key usage extension places additional restrictions on the
796 certificate uses. If this extension is present (whether critical or not)
797 the key can only be used for the purposes specified.
799 A complete description of each test is given below. The comments about
800 basicConstraints and keyUsage and V1 certificates above apply to B<all>
808 The extended key usage extension must be absent or include the "web client
809 authentication" OID. keyUsage must be absent or it must have the
810 digitalSignature bit set. Netscape certificate type must be absent or it must
811 have the SSL client bit set.
813 =item B<SSL Client CA>
815 The extended key usage extension must be absent or include the "web client
816 authentication" OID. Netscape certificate type must be absent or it must have
817 the SSL CA bit set: this is used as a work around if the basicConstraints
822 The extended key usage extension must be absent or include the "web server
823 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
824 must have the digitalSignature, the keyEncipherment set or both bits set.
825 Netscape certificate type must be absent or have the SSL server bit set.
827 =item B<SSL Server CA>
829 The extended key usage extension must be absent or include the "web server
830 authentication" and/or one of the SGC OIDs. Netscape certificate type must
831 be absent or the SSL CA bit must be set: this is used as a work around if the
832 basicConstraints extension is absent.
834 =item B<Netscape SSL Server>
836 For Netscape SSL clients to connect to an SSL server it must have the
837 keyEncipherment bit set if the keyUsage extension is present. This isn't
838 always valid because some cipher suites use the key for digital signing.
839 Otherwise it is the same as a normal SSL server.
841 =item B<Common S/MIME Client Tests>
843 The extended key usage extension must be absent or include the "email
844 protection" OID. Netscape certificate type must be absent or should have the
845 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
846 then the SSL client bit is tolerated as an alternative but a warning is shown:
847 this is because some Verisign certificates don't set the S/MIME bit.
849 =item B<S/MIME Signing>
851 In addition to the common S/MIME client tests the digitalSignature bit must
852 be set if the keyUsage extension is present.
854 =item B<S/MIME Encryption>
856 In addition to the common S/MIME tests the keyEncipherment bit must be set
857 if the keyUsage extension is present.
861 The extended key usage extension must be absent or include the "email
862 protection" OID. Netscape certificate type must be absent or must have the
863 S/MIME CA bit set: this is used as a work around if the basicConstraints
868 The keyUsage extension must be absent or it must have the CRL signing bit
871 =item B<CRL Signing CA>
873 The normal CA tests apply. Except in this case the basicConstraints extension
880 Extensions in certificates are not transferred to certificate requests and
883 It is possible to produce invalid certificates or requests by specifying the
884 wrong private key or using inconsistent options in some cases: these should
887 There should be options to explicitly set such things as start and end
888 dates rather than an offset from the current time.
892 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
893 L<gendsa(1)>, L<verify(1)>,
898 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
899 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
900 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
901 canonical version of the DN using SHA1. This means that any directories using
902 the old form must have their links rebuilt using B<c_rehash> or similar.
906 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
908 Licensed under the OpenSSL license (the "License"). You may not use
909 this file except in compliance with the License. You can obtain a copy
910 in the file LICENSE in the source distribution or at
911 L<https://www.openssl.org/source/license.html>.