6 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
80 =item B<-inform DER|PEM|NET>
82 This specifies the input format normally the command will expect an X509
83 certificate but this can change if other options such as B<-req> are
84 present. The DER format is the DER encoding of the certificate and PEM
85 is the base64 encoding of the DER encoding with header and footer lines
86 added. The NET option is an obscure Netscape server format that is now
89 =item B<-outform DER|PEM|NET>
91 This specifies the output format, the options have the same meaning as the
96 This specifies the input filename to read a certificate from or standard input
97 if this option is not specified.
99 =item B<-out filename>
101 This specifies the output filename to write to or standard output by
107 This affects any signing or display option that uses a message
108 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options.
109 Any digest supported by the OpenSSL B<dgst> command can be used.
110 If not specified then SHA1 is used.
111 Note that if a DSA key is used for signing, then this flag is ignored
116 specifying an engine (by its unique B<id> string) will cause B<x509>
117 to attempt to obtain a functional reference to the specified engine,
118 thus initialising it if needed. The engine will then be set as the default
119 for all available algorithms.
123 =head2 DISPLAY OPTIONS
125 Note: the B<-alias> and B<-purpose> options are also display options
126 but are described in the B<TRUST SETTINGS> section.
132 prints out the certificate in text form. Full details are output including the
133 public key, signature algorithms, issuer and subject names, serial number
134 any extensions present and any trust settings.
136 =item B<-certopt option>
138 customise the output format used with B<-text>. The B<option> argument can be
139 a single option or multiple options separated by commas. The B<-certopt> switch
140 may be also be used more than once to set multiple options. See the B<TEXT OPTIONS>
141 section for more information.
145 this option prevents output of the encoded version of the request.
149 outputs the the certificate's SubjectPublicKeyInfo block in PEM format.
153 this option prints out the value of the modulus of the public key
154 contained in the certificate.
158 outputs the certificate serial number.
160 =item B<-subject_hash>
162 outputs the "hash" of the certificate subject name. This is used in OpenSSL to
163 form an index to allow certificates in a directory to be looked up by subject
166 =item B<-issuer_hash>
168 outputs the "hash" of the certificate issuer name.
172 outputs the OCSP hash values for the subject name and public key.
176 synonym for "-subject_hash" for backward compatibility reasons.
178 =item B<-subject_hash_old>
180 outputs the "hash" of the certificate subject name using the older algorithm
181 as used by OpenSSL versions before 1.0.0.
183 =item B<-issuer_hash_old>
185 outputs the "hash" of the certificate issuer name using the older algorithm
186 as used by OpenSSL versions before 1.0.0.
190 outputs the subject name.
194 outputs the issuer name.
196 =item B<-nameopt option>
198 option which determines how the subject or issuer names are displayed. The
199 B<option> argument can be a single option or multiple options separated by
200 commas. Alternatively the B<-nameopt> switch may be used more than once to
201 set multiple options. See the B<NAME OPTIONS> section for more information.
205 outputs the email address(es) if any.
209 outputs the OCSP responder address(es) if any.
213 prints out the start date of the certificate, that is the notBefore date.
217 prints out the expiry date of the certificate, that is the notAfter date.
221 prints out the start and expiry dates of a certificate.
223 =item B<-checkend arg>
225 checks if the certificate expires within the next B<arg> seconds and exits
226 non-zero if yes it will expire or zero if not.
228 =item B<-fingerprint>
230 prints out the digest of the DER encoded version of the whole certificate
231 (see digest options).
235 this outputs the certificate in the form of a C source file.
239 =head2 TRUST SETTINGS
241 Please note these options are currently experimental and may well change.
243 A B<trusted certificate> is an ordinary certificate which has several
244 additional pieces of information attached to it such as the permitted
245 and prohibited uses of the certificate and an "alias".
247 Normally when a certificate is being verified at least one certificate
248 must be "trusted". By default a trusted certificate must be stored
249 locally and must be a root CA: any certificate chain ending in this CA
250 is then usable for any purpose.
252 Trust settings currently are only used with a root CA. They allow a finer
253 control over the purposes the root CA can be used for. For example a CA
254 may be trusted for SSL client but not SSL server use.
256 See the description of the B<verify> utility for more information on the
257 meaning of trust settings.
259 Future versions of OpenSSL will recognize trust settings on any
260 certificate: not just root CAs.
267 this causes B<x509> to output a B<trusted> certificate. An ordinary
268 or trusted certificate can be input but by default an ordinary
269 certificate is output and any trust settings are discarded. With the
270 B<-trustout> option a trusted certificate is output. A trusted
271 certificate is automatically output if any trust settings are modified.
273 =item B<-setalias arg>
275 sets the alias of the certificate. This will allow the certificate
276 to be referred to using a nickname for example "Steve's Certificate".
280 outputs the certificate alias, if any.
284 clears all the permitted or trusted uses of the certificate.
288 clears all the prohibited or rejected uses of the certificate.
290 =item B<-addtrust arg>
292 adds a trusted certificate use.
293 Any object name can be used here but currently only B<clientAuth> (SSL client
294 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
295 B<anyExtendedKeyUsage> are used.
296 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
297 enables all purposes when trusted.
298 Other OpenSSL applications may define additional uses.
300 =item B<-addreject arg>
302 adds a prohibited use. It accepts the same values as the B<-addtrust>
307 this option performs tests on the certificate extensions and outputs
308 the results. For a more complete description see the B<CERTIFICATE
313 =head2 SIGNING OPTIONS
315 The B<x509> utility can be used to sign certificates and requests: it
316 can thus behave like a "mini CA".
320 =item B<-signkey filename>
322 this option causes the input file to be self signed using the supplied
325 If the input file is a certificate it sets the issuer name to the
326 subject name (i.e. makes it self signed) changes the public key to the
327 supplied value and changes the start and end dates. The start date is
328 set to the current time and the end date is set to a value determined
329 by the B<-days> option. Any certificate extensions are retained unless
330 the B<-clrext> option is supplied.
332 If the input is a certificate request then a self signed certificate
333 is created using the supplied private key using the subject name in
338 the key password source. For more information about the format of B<arg>
339 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
343 delete any extensions from a certificate. This option is used when a
344 certificate is being created from another certificate (for example with
345 the B<-signkey> or the B<-CA> options). Normally all extensions are
348 =item B<-keyform PEM|DER>
350 specifies the format (DER or PEM) of the private key file used in the
355 specifies the number of days to make a certificate valid for. The default
360 converts a certificate into a certificate request. The B<-signkey> option
361 is used to pass the required private key.
365 by default a certificate is expected on input. With this option a
366 certificate request is expected instead.
368 =item B<-set_serial n>
370 specifies the serial number to use. This option can be used with either
371 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
372 option the serial number file (as specified by the B<-CAserial> or
373 B<-CAcreateserial> options) is not used.
375 The serial number can be decimal or hex (if preceded by B<0x>).
377 =item B<-CA filename>
379 specifies the CA certificate to be used for signing. When this option is
380 present B<x509> behaves like a "mini CA". The input file is signed by this
381 CA using this option: that is its issuer name is set to the subject name
382 of the CA and it is digitally signed using the CAs private key.
384 This option is normally combined with the B<-req> option. Without the
385 B<-req> option the input is a certificate which must be self signed.
387 =item B<-CAkey filename>
389 sets the CA private key to sign a certificate with. If this option is
390 not specified then it is assumed that the CA private key is present in
391 the CA certificate file.
393 =item B<-CAserial filename>
395 sets the CA serial number file to use.
397 When the B<-CA> option is used to sign a certificate it uses a serial
398 number specified in a file. This file consist of one line containing
399 an even number of hex digits with the serial number to use. After each
400 use the serial number is incremented and written out to the file again.
402 The default filename consists of the CA certificate file base name with
403 ".srl" appended. For example if the CA certificate file is called
404 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
406 =item B<-CAcreateserial>
408 with this option the CA serial number file is created if it does not exist:
409 it will contain the serial number "02" and the certificate being signed will
410 have the 1 as its serial number. If the B<-CA> option is specified
411 and the serial number file does not exist a random number is generated;
412 this is the recommended practice.
414 =item B<-extfile filename>
416 file containing certificate extensions to use. If not specified then
417 no extensions are added to the certificate.
419 =item B<-extensions section>
421 the section to add certificate extensions from. If this option is not
422 specified then the extensions should either be contained in the unnamed
423 (default) section or the default section should contain a variable called
424 "extensions" which contains the section to use. See the
425 L<x509v3_config(5)> manual page for details of the
426 extension section format.
428 =item B<-force_pubkey key>
430 when a certificate is created set its public key to B<key> instead of the
431 key in the certificate or certificate request. This option is useful for
432 creating certificates where the algorithm can't normally sign requests, for
435 The format or B<key> can be specified using the B<-keyform> option.
441 The B<nameopt> command line switch determines how the subject and issuer
442 names are displayed. If no B<nameopt> switch is present the default "oneline"
443 format is used which is compatible with previous versions of OpenSSL.
444 Each option is described in detail below, all options can be preceded by
445 a B<-> to turn the option off. Only the first four will normally be used.
455 displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
456 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
457 B<sep_comma_plus>, B<dn_rev> and B<sname>.
461 a oneline format which is more readable than RFC2253. It is equivalent to
462 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
463 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
464 options. This is the I<default> of no name options are given explicitely.
468 a multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
469 B<space_eq>, B<lname> and B<align>.
473 escape the "special" characters required by RFC2253 in a field That is
474 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
475 and a space character at the beginning or end of a string.
479 escape control characters. That is those with ASCII values less than
480 0x20 (space) and the delete (0x7f) character. They are escaped using the
481 RFC2253 \XX notation (where XX are two hex digits representing the
486 escape characters with the MSB set, that is with ASCII values larger than
491 escapes some characters by surrounding the whole string with B<"> characters,
492 without the option all escaping is done with the B<\> character.
496 convert all strings to UTF8 format first. This is required by RFC2253. If
497 you are lucky enough to have a UTF8 compatible terminal then the use
498 of this option (and B<not> setting B<esc_msb>) may result in the correct
499 display of multibyte (international) characters. Is this option is not
500 present then multibyte characters larger than 0xff will be represented
501 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
502 Also if this option is off any UTF8Strings will be converted to their
503 character form first.
507 this option does not attempt to interpret multibyte characters in any
508 way. That is their content octets are merely dumped as though one octet
509 represents each character. This is useful for diagnostic purposes but
510 will result in rather odd looking output.
514 show the type of the ASN1 character string. The type precedes the
515 field contents. For example "BMPSTRING: Hello World".
519 when this option is set any fields that need to be hexdumped will
520 be dumped using the DER encoding of the field. Otherwise just the
521 content octets will be displayed. Both options use the RFC2253
526 dump non character string types (for example OCTET STRING) if this
527 option is not set then non character string types will be displayed
528 as though each content octet represents a single character.
532 dump all fields. This option when used with B<dump_der> allows the
533 DER encoding of the structure to be unambiguously determined.
535 =item B<dump_unknown>
537 dump any field whose OID is not recognised by OpenSSL.
539 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
542 these options determine the field separators. The first character is
543 between RDNs and the second between multiple AVAs (multiple AVAs are
544 very rare and their use is discouraged). The options ending in
545 "space" additionally place a space after the separator to make it
546 more readable. The B<sep_multiline> uses a linefeed character for
547 the RDN separator and a spaced B<+> for the AVA separator. It also
548 indents the fields by four characters. If no field separator is specified
549 then B<sep_comma_plus_space> is used by default.
553 reverse the fields of the DN. This is required by RFC2253. As a side
554 effect this also reverses the order of multiple AVAs but this is
557 =item B<nofname>, B<sname>, B<lname>, B<oid>
559 these options alter how the field name is displayed. B<nofname> does
560 not display the field at all. B<sname> uses the "short name" form
561 (CN for commonName for example). B<lname> uses the long form.
562 B<oid> represents the OID in numerical form and is useful for
567 align field values for a more readable output. Only usable with
572 places spaces round the B<=> character which follows the field
579 As well as customising the name output format, it is also possible to
580 customise the actual fields printed using the B<certopt> options when
581 the B<text> option is present. The default behaviour is to print all fields.
587 use the old format. This is equivalent to specifying no output options at all.
591 don't print header information: that is the lines saying "Certificate" and "Data".
595 don't print out the version number.
599 don't print out the serial number.
603 don't print out the signature algorithm used.
607 don't print the validity, that is the B<notBefore> and B<notAfter> fields.
611 don't print out the subject name.
615 don't print out the issuer name.
619 don't print out the public key.
623 don't give a hexadecimal dump of the certificate signature.
627 don't print out certificate trust information.
629 =item B<no_extensions>
631 don't print out any X509V3 extensions.
635 retain default extension behaviour: attempt to print out unsupported certificate extensions.
639 print an error message for unsupported certificate extensions.
643 ASN1 parse unsupported extensions.
647 hex dump unsupported extensions.
651 the value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>, B<no_header>,
652 B<no_version>, B<no_sigdump> and B<no_signame>.
658 Note: in these examples the '\' means the example should be all on one
661 Display the contents of a certificate:
663 openssl x509 -in cert.pem -noout -text
665 Display the certificate serial number:
667 openssl x509 -in cert.pem -noout -serial
669 Display the certificate subject name:
671 openssl x509 -in cert.pem -noout -subject
673 Display the certificate subject name in RFC2253 form:
675 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
677 Display the certificate subject name in oneline form on a terminal
680 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
682 Display the certificate MD5 fingerprint:
684 openssl x509 -in cert.pem -noout -fingerprint
686 Display the certificate SHA1 fingerprint:
688 openssl x509 -sha1 -in cert.pem -noout -fingerprint
690 Convert a certificate from PEM to DER format:
692 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
694 Convert a certificate to a certificate request:
696 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
698 Convert a certificate request into a self signed certificate using
701 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
702 -signkey key.pem -out cacert.pem
704 Sign a certificate request using the CA certificate above and add user
705 certificate extensions:
707 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
708 -CA cacert.pem -CAkey key.pem -CAcreateserial
711 Set a certificate to be trusted for SSL client use and change set its alias to
714 openssl x509 -in cert.pem -addtrust clientAuth \
715 -setalias "Steve's Class 1 CA" -out trust.pem
719 The PEM format uses the header and footer lines:
721 -----BEGIN CERTIFICATE-----
722 -----END CERTIFICATE-----
724 it will also handle files containing:
726 -----BEGIN X509 CERTIFICATE-----
727 -----END X509 CERTIFICATE-----
729 Trusted certificates have the lines
731 -----BEGIN TRUSTED CERTIFICATE-----
732 -----END TRUSTED CERTIFICATE-----
734 The conversion to UTF8 format used with the name options assumes that
735 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
736 and MSIE do this as do many certificates. So although this is incorrect
737 it is more likely to display the majority of certificates correctly.
739 The B<-fingerprint> option takes the digest of the DER encoded certificate.
740 This is commonly called a "fingerprint". Because of the nature of message
741 digests the fingerprint of a certificate is unique to that certificate and
742 two certificates with the same fingerprint can be considered to be the same.
744 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
746 The B<-email> option searches the subject name and the subject alternative
747 name extension. Only unique email addresses will be printed out: it will
748 not print the same address more than once.
750 =head1 CERTIFICATE EXTENSIONS
752 The B<-purpose> option checks the certificate extensions and determines
753 what the certificate can be used for. The actual checks done are rather
754 complex and include various hacks and workarounds to handle broken
755 certificates and software.
757 The same code is used when verifying untrusted certificates in chains
758 so this section is useful if a chain is rejected by the verify code.
760 The basicConstraints extension CA flag is used to determine whether the
761 certificate can be used as a CA. If the CA flag is true then it is a CA,
762 if the CA flag is false then it is not a CA. B<All> CAs should have the
765 If the basicConstraints extension is absent then the certificate is
766 considered to be a "possible CA" other extensions are checked according
767 to the intended use of the certificate. A warning is given in this case
768 because the certificate should really not be regarded as a CA: however
769 it is allowed to be a CA to work around some broken software.
771 If the certificate is a V1 certificate (and thus has no extensions) and
772 it is self signed it is also assumed to be a CA but a warning is again
773 given: this is to work around the problem of Verisign roots which are V1
774 self signed certificates.
776 If the keyUsage extension is present then additional restraints are
777 made on the uses of the certificate. A CA certificate B<must> have the
778 keyCertSign bit set if the keyUsage extension is present.
780 The extended key usage extension places additional restrictions on the
781 certificate uses. If this extension is present (whether critical or not)
782 the key can only be used for the purposes specified.
784 A complete description of each test is given below. The comments about
785 basicConstraints and keyUsage and V1 certificates above apply to B<all>
793 The extended key usage extension must be absent or include the "web client
794 authentication" OID. keyUsage must be absent or it must have the
795 digitalSignature bit set. Netscape certificate type must be absent or it must
796 have the SSL client bit set.
798 =item B<SSL Client CA>
800 The extended key usage extension must be absent or include the "web client
801 authentication" OID. Netscape certificate type must be absent or it must have
802 the SSL CA bit set: this is used as a work around if the basicConstraints
807 The extended key usage extension must be absent or include the "web server
808 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
809 must have the digitalSignature, the keyEncipherment set or both bits set.
810 Netscape certificate type must be absent or have the SSL server bit set.
812 =item B<SSL Server CA>
814 The extended key usage extension must be absent or include the "web server
815 authentication" and/or one of the SGC OIDs. Netscape certificate type must
816 be absent or the SSL CA bit must be set: this is used as a work around if the
817 basicConstraints extension is absent.
819 =item B<Netscape SSL Server>
821 For Netscape SSL clients to connect to an SSL server it must have the
822 keyEncipherment bit set if the keyUsage extension is present. This isn't
823 always valid because some cipher suites use the key for digital signing.
824 Otherwise it is the same as a normal SSL server.
826 =item B<Common S/MIME Client Tests>
828 The extended key usage extension must be absent or include the "email
829 protection" OID. Netscape certificate type must be absent or should have the
830 S/MIME bit set. If the S/MIME bit is not set in netscape certificate type
831 then the SSL client bit is tolerated as an alternative but a warning is shown:
832 this is because some Verisign certificates don't set the S/MIME bit.
834 =item B<S/MIME Signing>
836 In addition to the common S/MIME client tests the digitalSignature bit must
837 be set if the keyUsage extension is present.
839 =item B<S/MIME Encryption>
841 In addition to the common S/MIME tests the keyEncipherment bit must be set
842 if the keyUsage extension is present.
846 The extended key usage extension must be absent or include the "email
847 protection" OID. Netscape certificate type must be absent or must have the
848 S/MIME CA bit set: this is used as a work around if the basicConstraints
853 The keyUsage extension must be absent or it must have the CRL signing bit
856 =item B<CRL Signing CA>
858 The normal CA tests apply. Except in this case the basicConstraints extension
865 Extensions in certificates are not transferred to certificate requests and
868 It is possible to produce invalid certificates or requests by specifying the
869 wrong private key or using inconsistent options in some cases: these should
872 There should be options to explicitly set such things as start and end
873 dates rather than an offset from the current time.
877 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
878 L<gendsa(1)>, L<verify(1)>,
883 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
884 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
885 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
886 canonical version of the DN using SHA1. This means that any directories using
887 the old form must have their links rebuilt using B<c_rehash> or similar.