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>]
66 The B<x509> command is a multi purpose certificate utility. It can be
67 used to display certificate information, convert certificates to
68 various forms, sign certificate requests like a "mini CA" or edit
69 certificate trust settings.
71 Since there are a large number of options they will split up into
76 =head2 Input, Output, and General Purpose Options
82 Print out a usage message.
84 =item B<-inform DER|PEM|NET>
86 This specifies the input format normally the command will expect an X509
87 certificate but this can change if other options such as B<-req> are
88 present. The DER format is the DER encoding of the certificate and PEM
89 is the base64 encoding of the DER encoding with header and footer lines
90 added. The NET option is an obscure Netscape server format that is now
93 =item B<-outform DER|PEM|NET>
95 This specifies the output format, the options have the same meaning as the
100 This specifies the input filename to read a certificate from or standard input
101 if this option is not specified.
103 =item B<-out filename>
105 This specifies the output filename to write to or standard output by
111 This affects any signing or display option that uses a message
112 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options.
113 Any digest supported by the OpenSSL B<dgst> command can be used.
114 If not specified then SHA1 is used with B<-fingerprint> or
115 the default digest for the signing algorithm is used, typically SHA256.
119 specifying an engine (by its unique B<id> string) will cause B<x509>
120 to attempt to obtain a functional reference to the specified engine,
121 thus initialising it if needed. The engine will then be set as the default
122 for all available algorithms.
126 =head2 Display Options
128 Note: the B<-alias> and B<-purpose> options are also display options
129 but are described in the B<TRUST SETTINGS> section.
135 prints out the certificate in text form. Full details are output including the
136 public key, signature algorithms, issuer and subject names, serial number
137 any extensions present and any trust settings.
139 =item B<-certopt option>
141 customise the output format used with B<-text>. The B<option> argument can be
142 a single option or multiple options separated by commas. The B<-certopt> switch
143 may be also be used more than once to set multiple options. See the B<TEXT OPTIONS>
144 section for more information.
148 this option prevents output of the encoded version of the request.
152 outputs the certificate's SubjectPublicKeyInfo block in PEM format.
156 this option prints out the value of the modulus of the public key
157 contained in the certificate.
161 outputs the certificate serial number.
163 =item B<-subject_hash>
165 outputs the "hash" of the certificate subject name. This is used in OpenSSL to
166 form an index to allow certificates in a directory to be looked up by subject
169 =item B<-issuer_hash>
171 outputs the "hash" of the certificate issuer name.
175 outputs the OCSP hash values for the subject name and public key.
179 synonym for "-subject_hash" for backward compatibility reasons.
181 =item B<-subject_hash_old>
183 outputs the "hash" of the certificate subject name using the older algorithm
184 as used by OpenSSL versions before 1.0.0.
186 =item B<-issuer_hash_old>
188 outputs the "hash" of the certificate issuer name using the older algorithm
189 as used by OpenSSL versions before 1.0.0.
193 outputs the subject name.
197 outputs the issuer name.
199 =item B<-nameopt option>
201 option which determines how the subject or issuer names are displayed. The
202 B<option> argument can be a single option or multiple options separated by
203 commas. Alternatively the B<-nameopt> switch may be used more than once to
204 set multiple options. See the B<NAME OPTIONS> section for more information.
208 outputs the email address(es) if any.
212 outputs the OCSP responder address(es) if any.
216 prints out the start date of the certificate, that is the notBefore date.
220 prints out the expiry date of the certificate, that is the notAfter date.
224 prints out the start and expiry dates of a certificate.
226 =item B<-checkend arg>
228 checks if the certificate expires within the next B<arg> seconds and exits
229 non-zero if yes it will expire or zero if not.
231 =item B<-fingerprint>
233 prints out the digest of the DER encoded version of the whole certificate
234 (see digest options).
238 this outputs the certificate in the form of a C source file.
242 =head2 Trust Settings
244 A B<trusted certificate> is an ordinary certificate which has several
245 additional pieces of information attached to it such as the permitted
246 and prohibited uses of the certificate and an "alias".
248 Normally when a certificate is being verified at least one certificate
249 must be "trusted". By default a trusted certificate must be stored
250 locally and must be a root CA: any certificate chain ending in this CA
251 is then usable for any purpose.
253 Trust settings currently are only used with a root CA. They allow a finer
254 control over the purposes the root CA can be used for. For example a CA
255 may be trusted for SSL client but not SSL server use.
257 See the description of the B<verify> utility for more information on the
258 meaning of trust settings.
260 Future versions of OpenSSL will recognize trust settings on any
261 certificate: not just root CAs.
268 this causes B<x509> to output a B<trusted> certificate. An ordinary
269 or trusted certificate can be input but by default an ordinary
270 certificate is output and any trust settings are discarded. With the
271 B<-trustout> option a trusted certificate is output. A trusted
272 certificate is automatically output if any trust settings are modified.
274 =item B<-setalias arg>
276 sets the alias of the certificate. This will allow the certificate
277 to be referred to using a nickname for example "Steve's Certificate".
281 outputs the certificate alias, if any.
285 clears all the permitted or trusted uses of the certificate.
289 clears all the prohibited or rejected uses of the certificate.
291 =item B<-addtrust arg>
293 adds a trusted certificate use.
294 Any object name can be used here but currently only B<clientAuth> (SSL client
295 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
296 B<anyExtendedKeyUsage> are used.
297 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
298 enables all purposes when trusted.
299 Other OpenSSL applications may define additional uses.
301 =item B<-addreject arg>
303 adds a prohibited use. It accepts the same values as the B<-addtrust>
308 this option performs tests on the certificate extensions and outputs
309 the results. For a more complete description see the B<CERTIFICATE
314 =head2 Signing Options
316 The B<x509> utility can be used to sign certificates and requests: it
317 can thus behave like a "mini CA".
321 =item B<-signkey filename>
323 this option causes the input file to be self signed using the supplied
326 If the input file is a certificate it sets the issuer name to the
327 subject name (i.e. makes it self signed) changes the public key to the
328 supplied value and changes the start and end dates. The start date is
329 set to the current time and the end date is set to a value determined
330 by the B<-days> option. Any certificate extensions are retained unless
331 the B<-clrext> option is supplied; this includes, for example, any existing
332 key identifier extensions.
334 If the input is a certificate request then a self signed certificate
335 is created using the supplied private key using the subject name in
340 the key password source. For more information about the format of B<arg>
341 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
345 delete any extensions from a certificate. This option is used when a
346 certificate is being created from another certificate (for example with
347 the B<-signkey> or the B<-CA> options). Normally all extensions are
350 =item B<-keyform PEM|DER>
352 specifies the format (DER or PEM) of the private key file used in the
357 specifies the number of days to make a certificate valid for. The default
362 converts a certificate into a certificate request. The B<-signkey> option
363 is used to pass the required private key.
367 by default a certificate is expected on input. With this option a
368 certificate request is expected instead.
370 =item B<-set_serial n>
372 specifies the serial number to use. This option can be used with either
373 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
374 option the serial number file (as specified by the B<-CAserial> or
375 B<-CAcreateserial> options) is not used.
377 The serial number can be decimal or hex (if preceded by B<0x>).
379 =item B<-CA filename>
381 specifies the CA certificate to be used for signing. When this option is
382 present B<x509> behaves like a "mini CA". The input file is signed by this
383 CA using this option: that is its issuer name is set to the subject name
384 of the CA and it is digitally signed using the CAs private key.
386 This option is normally combined with the B<-req> option. Without the
387 B<-req> option the input is a certificate which must be self signed.
389 =item B<-CAkey filename>
391 sets the CA private key to sign a certificate with. If this option is
392 not specified then it is assumed that the CA private key is present in
393 the CA certificate file.
395 =item B<-CAserial filename>
397 sets the CA serial number file to use.
399 When the B<-CA> option is used to sign a certificate it uses a serial
400 number specified in a file. This file consist of one line containing
401 an even number of hex digits with the serial number to use. After each
402 use the serial number is incremented and written out to the file again.
404 The default filename consists of the CA certificate file base name with
405 ".srl" appended. For example if the CA certificate file is called
406 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
408 =item B<-CAcreateserial>
410 with this option the CA serial number file is created if it does not exist:
411 it will contain the serial number "02" and the certificate being signed will
412 have the 1 as its serial number. If the B<-CA> option is specified
413 and the serial number file does not exist a random number is generated;
414 this is the recommended practice.
416 =item B<-extfile filename>
418 file containing certificate extensions to use. If not specified then
419 no extensions are added to the certificate.
421 =item B<-extensions section>
423 the section to add certificate extensions from. If this option is not
424 specified then the extensions should either be contained in the unnamed
425 (default) section or the default section should contain a variable called
426 "extensions" which contains the section to use. See the
427 L<x509v3_config(5)> manual page for details of the
428 extension section format.
430 =item B<-force_pubkey key>
432 when a certificate is created set its public key to B<key> instead of the
433 key in the certificate or certificate request. This option is useful for
434 creating certificates where the algorithm can't normally sign requests, for
437 The format or B<key> can be specified using the B<-keyform> option.
443 The B<nameopt> command line switch determines how the subject and issuer
444 names are displayed. If no B<nameopt> switch is present the default "oneline"
445 format is used which is compatible with previous versions of OpenSSL.
446 Each option is described in detail below, all options can be preceded by
447 a B<-> to turn the option off. Only the first four will normally be used.
457 displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
458 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
459 B<sep_comma_plus>, B<dn_rev> and B<sname>.
463 a oneline format which is more readable than RFC2253. It is equivalent to
464 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
465 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
466 options. This is the I<default> of no name options are given explicitly.
470 a multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
471 B<space_eq>, B<lname> and B<align>.
475 escape the "special" characters required by RFC2253 in a field. That is
476 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
477 and a space character at the beginning or end of a string.
481 escape the "special" characters required by RFC2254 in a field. That is
482 the B<NUL> character as well as and B<()*>.
486 escape control characters. That is those with ASCII values less than
487 0x20 (space) and the delete (0x7f) character. They are escaped using the
488 RFC2253 \XX notation (where XX are two hex digits representing the
493 escape characters with the MSB set, that is with ASCII values larger than
498 escapes some characters by surrounding the whole string with B<"> characters,
499 without the option all escaping is done with the B<\> character.
503 convert all strings to UTF8 format first. This is required by RFC2253. If
504 you are lucky enough to have a UTF8 compatible terminal then the use
505 of this option (and B<not> setting B<esc_msb>) may result in the correct
506 display of multibyte (international) characters. Is this option is not
507 present then multibyte characters larger than 0xff will be represented
508 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
509 Also if this option is off any UTF8Strings will be converted to their
510 character form first.
514 this option does not attempt to interpret multibyte characters in any
515 way. That is their content octets are merely dumped as though one octet
516 represents each character. This is useful for diagnostic purposes but
517 will result in rather odd looking output.
521 show the type of the ASN1 character string. The type precedes the
522 field contents. For example "BMPSTRING: Hello World".
526 when this option is set any fields that need to be hexdumped will
527 be dumped using the DER encoding of the field. Otherwise just the
528 content octets will be displayed. Both options use the RFC2253
533 dump non character string types (for example OCTET STRING) if this
534 option is not set then non character string types will be displayed
535 as though each content octet represents a single character.
539 dump all fields. This option when used with B<dump_der> allows the
540 DER encoding of the structure to be unambiguously determined.
542 =item B<dump_unknown>
544 dump any field whose OID is not recognised by OpenSSL.
546 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
549 these options determine the field separators. The first character is
550 between RDNs and the second between multiple AVAs (multiple AVAs are
551 very rare and their use is discouraged). The options ending in
552 "space" additionally place a space after the separator to make it
553 more readable. The B<sep_multiline> uses a linefeed character for
554 the RDN separator and a spaced B<+> for the AVA separator. It also
555 indents the fields by four characters. If no field separator is specified
556 then B<sep_comma_plus_space> is used by default.
560 reverse the fields of the DN. This is required by RFC2253. As a side
561 effect this also reverses the order of multiple AVAs but this is
564 =item B<nofname>, B<sname>, B<lname>, B<oid>
566 these options alter how the field name is displayed. B<nofname> does
567 not display the field at all. B<sname> uses the "short name" form
568 (CN for commonName for example). B<lname> uses the long form.
569 B<oid> represents the OID in numerical form and is useful for
574 align field values for a more readable output. Only usable with
579 places spaces round the B<=> character which follows the field
586 As well as customising the name output format, it is also possible to
587 customise the actual fields printed using the B<certopt> options when
588 the B<text> option is present. The default behaviour is to print all fields.
594 use the old format. This is equivalent to specifying no output options at all.
598 don't print header information: that is the lines saying "Certificate" and "Data".
602 don't print out the version number.
606 don't print out the serial number.
610 don't print out the signature algorithm used.
614 don't print the validity, that is the B<notBefore> and B<notAfter> fields.
618 don't print out the subject name.
622 don't print out the issuer name.
626 don't print out the public key.
630 don't give a hexadecimal dump of the certificate signature.
634 don't print out certificate trust information.
636 =item B<no_extensions>
638 don't print out any X509V3 extensions.
642 retain default extension behaviour: attempt to print out unsupported certificate extensions.
646 print an error message for unsupported certificate extensions.
650 ASN1 parse unsupported extensions.
654 hex dump unsupported extensions.
658 the value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
659 B<no_header>, and B<no_version>.
665 Note: in these examples the '\' means the example should be all on one
668 Display the contents of a certificate:
670 openssl x509 -in cert.pem -noout -text
672 Display the certificate serial number:
674 openssl x509 -in cert.pem -noout -serial
676 Display the certificate subject name:
678 openssl x509 -in cert.pem -noout -subject
680 Display the certificate subject name in RFC2253 form:
682 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
684 Display the certificate subject name in oneline form on a terminal
687 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
689 Display the certificate MD5 fingerprint:
691 openssl x509 -in cert.pem -noout -fingerprint
693 Display the certificate SHA1 fingerprint:
695 openssl x509 -sha1 -in cert.pem -noout -fingerprint
697 Convert a certificate from PEM to DER format:
699 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
701 Convert a certificate to a certificate request:
703 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
705 Convert a certificate request into a self signed certificate using
708 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
709 -signkey key.pem -out cacert.pem
711 Sign a certificate request using the CA certificate above and add user
712 certificate extensions:
714 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
715 -CA cacert.pem -CAkey key.pem -CAcreateserial
718 Set a certificate to be trusted for SSL client use and change set its alias to
721 openssl x509 -in cert.pem -addtrust clientAuth \
722 -setalias "Steve's Class 1 CA" -out trust.pem
726 The PEM format uses the header and footer lines:
728 -----BEGIN CERTIFICATE-----
729 -----END CERTIFICATE-----
731 it will also handle files containing:
733 -----BEGIN X509 CERTIFICATE-----
734 -----END X509 CERTIFICATE-----
736 Trusted certificates have the lines
738 -----BEGIN TRUSTED CERTIFICATE-----
739 -----END TRUSTED CERTIFICATE-----
741 The conversion to UTF8 format used with the name options assumes that
742 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
743 and MSIE do this as do many certificates. So although this is incorrect
744 it is more likely to display the majority of certificates correctly.
746 The B<-fingerprint> option takes the digest of the DER encoded certificate.
747 This is commonly called a "fingerprint". Because of the nature of message
748 digests the fingerprint of a certificate is unique to that certificate and
749 two certificates with the same fingerprint can be considered to be the same.
751 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
753 The B<-email> option searches the subject name and the subject alternative
754 name extension. Only unique email addresses will be printed out: it will
755 not print the same address more than once.
757 =head1 CERTIFICATE EXTENSIONS
759 The B<-purpose> option checks the certificate extensions and determines
760 what the certificate can be used for. The actual checks done are rather
761 complex and include various hacks and workarounds to handle broken
762 certificates and software.
764 The same code is used when verifying untrusted certificates in chains
765 so this section is useful if a chain is rejected by the verify code.
767 The basicConstraints extension CA flag is used to determine whether the
768 certificate can be used as a CA. If the CA flag is true then it is a CA,
769 if the CA flag is false then it is not a CA. B<All> CAs should have the
772 If the basicConstraints extension is absent then the certificate is
773 considered to be a "possible CA" other extensions are checked according
774 to the intended use of the certificate. A warning is given in this case
775 because the certificate should really not be regarded as a CA: however
776 it is allowed to be a CA to work around some broken software.
778 If the certificate is a V1 certificate (and thus has no extensions) and
779 it is self signed it is also assumed to be a CA but a warning is again
780 given: this is to work around the problem of Verisign roots which are V1
781 self signed certificates.
783 If the keyUsage extension is present then additional restraints are
784 made on the uses of the certificate. A CA certificate B<must> have the
785 keyCertSign bit set if the keyUsage extension is present.
787 The extended key usage extension places additional restrictions on the
788 certificate uses. If this extension is present (whether critical or not)
789 the key can only be used for the purposes specified.
791 A complete description of each test is given below. The comments about
792 basicConstraints and keyUsage and V1 certificates above apply to B<all>
800 The extended key usage extension must be absent or include the "web client
801 authentication" OID. keyUsage must be absent or it must have the
802 digitalSignature bit set. Netscape certificate type must be absent or it must
803 have the SSL client bit set.
805 =item B<SSL Client CA>
807 The extended key usage extension must be absent or include the "web client
808 authentication" OID. Netscape certificate type must be absent or it must have
809 the SSL CA bit set: this is used as a work around if the basicConstraints
814 The extended key usage extension must be absent or include the "web server
815 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
816 must have the digitalSignature, the keyEncipherment set or both bits set.
817 Netscape certificate type must be absent or have the SSL server bit set.
819 =item B<SSL Server CA>
821 The extended key usage extension must be absent or include the "web server
822 authentication" and/or one of the SGC OIDs. Netscape certificate type must
823 be absent or the SSL CA bit must be set: this is used as a work around if the
824 basicConstraints extension is absent.
826 =item B<Netscape SSL Server>
828 For Netscape SSL clients to connect to an SSL server it must have the
829 keyEncipherment bit set if the keyUsage extension is present. This isn't
830 always valid because some cipher suites use the key for digital signing.
831 Otherwise it is the same as a normal SSL server.
833 =item B<Common S/MIME Client Tests>
835 The extended key usage extension must be absent or include the "email
836 protection" OID. Netscape certificate type must be absent or should have the
837 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
838 then the SSL client bit is tolerated as an alternative but a warning is shown:
839 this is because some Verisign certificates don't set the S/MIME bit.
841 =item B<S/MIME Signing>
843 In addition to the common S/MIME client tests the digitalSignature bit must
844 be set if the keyUsage extension is present.
846 =item B<S/MIME Encryption>
848 In addition to the common S/MIME tests the keyEncipherment bit must be set
849 if the keyUsage extension is present.
853 The extended key usage extension must be absent or include the "email
854 protection" OID. Netscape certificate type must be absent or must have the
855 S/MIME CA bit set: this is used as a work around if the basicConstraints
860 The keyUsage extension must be absent or it must have the CRL signing bit
863 =item B<CRL Signing CA>
865 The normal CA tests apply. Except in this case the basicConstraints extension
872 Extensions in certificates are not transferred to certificate requests and
875 It is possible to produce invalid certificates or requests by specifying the
876 wrong private key or using inconsistent options in some cases: these should
879 There should be options to explicitly set such things as start and end
880 dates rather than an offset from the current time.
884 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
885 L<gendsa(1)>, L<verify(1)>,
890 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
891 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
892 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
893 canonical version of the DN using SHA1. This means that any directories using
894 the old form must have their links rebuilt using B<c_rehash> or similar.
898 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
900 Licensed under the OpenSSL license (the "License"). You may not use
901 this file except in compliance with the License. You can obtain a copy
902 in the file LICENSE in the source distribution or at
903 L<https://www.openssl.org/source/license.html>.