7 x509 - Certificate display and signing utility
12 [B<-inform DER|PEM|NET>]
13 [B<-outform DER|PEM|NET>]
16 [B<-CAkeyform DER|PEM>]
47 [B<-signkey filename>]
54 [B<-CAserial filename>]
55 [B<-force_pubkey key>]
59 [B<-md2|-md5|-sha1|-mdc2>]
61 [B<-extfile filename>]
62 [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
81 =item B<-inform DER|PEM|NET>
83 This specifies the input format normally the command will expect an X509
84 certificate but this can change if other options such as B<-req> are
85 present. The DER format is the DER encoding of the certificate and PEM
86 is the base64 encoding of the DER encoding with header and footer lines
87 added. The NET option is an obscure Netscape server format that is now
90 =item B<-outform DER|PEM|NET>
92 This specifies the output format, the options have the same meaning as the
97 This specifies the input filename to read a certificate from or standard input
98 if this option is not specified.
100 =item B<-out filename>
102 This specifies the output filename to write to or standard output by
105 =item B<-md2|-md5|-sha1|-mdc2>
107 the digest to use. This affects any signing or display option that uses a message
108 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options. If not
109 specified then SHA1 is used. If the key being used to sign with is a DSA key
110 then this option has no effect: SHA1 is always used with DSA keys.
114 specifying an engine (by its unique B<id> string) will cause B<x509>
115 to attempt to obtain a functional reference to the specified engine,
116 thus initialising it if needed. The engine will then be set as the default
117 for all available algorithms.
121 =head2 DISPLAY OPTIONS
123 Note: the B<-alias> and B<-purpose> options are also display options
124 but are described in the B<TRUST SETTINGS> section.
130 prints out the certificate in text form. Full details are output including the
131 public key, signature algorithms, issuer and subject names, serial number
132 any extensions present and any trust settings.
134 =item B<-certopt option>
136 customise the output format used with B<-text>. The B<option> argument can be
137 a single option or multiple options separated by commas. The B<-certopt> switch
138 may be also be used more than once to set multiple options. See the B<TEXT OPTIONS>
139 section for more information.
143 this option prevents output of the encoded version of the request.
147 outputs the the certificate's SubjectPublicKeyInfo block in PEM format.
151 this option prints out the value of the modulus of the public key
152 contained in the certificate.
156 outputs the certificate serial number.
158 =item B<-subject_hash>
160 outputs the "hash" of the certificate subject name. This is used in OpenSSL to
161 form an index to allow certificates in a directory to be looked up by subject
164 =item B<-issuer_hash>
166 outputs the "hash" of the certificate issuer name.
170 outputs the OCSP hash values for the subject name and public key.
174 synonym for "-subject_hash" for backward compatibility reasons.
176 =item B<-subject_hash_old>
178 outputs the "hash" of the certificate subject name using the older algorithm
179 as used by OpenSSL versions before 1.0.0.
181 =item B<-issuer_hash_old>
183 outputs the "hash" of the certificate issuer name using the older algorithm
184 as used by OpenSSL versions before 1.0.0.
188 outputs the subject name.
192 outputs the issuer name.
194 =item B<-nameopt option>
196 option which determines how the subject or issuer names are displayed. The
197 B<option> argument can be a single option or multiple options separated by
198 commas. Alternatively the B<-nameopt> switch may be used more than once to
199 set multiple options. See the B<NAME OPTIONS> section for more information.
203 outputs the email address(es) if any.
207 outputs the OCSP responder address(es) if any.
211 prints out the start date of the certificate, that is the notBefore date.
215 prints out the expiry date of the certificate, that is the notAfter date.
219 prints out the start and expiry dates of a certificate.
221 =item B<-checkend arg>
223 checks if the certificate expires within the next B<arg> seconds and exits
224 non-zero if yes it will expire or zero if not.
226 =item B<-fingerprint>
228 Calculates and outputs the digest of the DER encoded version of the entire
229 certificate (see digest options).
230 This is commonly called a "fingerprint". Because of the nature of message
231 digests, the fingerprint of a certificate is unique to that certificate and
232 two certificates with the same fingerprint can be considered to be the same.
236 this outputs the certificate in the form of a C source file.
240 =head2 TRUST SETTINGS
242 Please note these options are currently experimental and may well change.
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. Any object name can be used here
294 but currently only B<clientAuth> (SSL client use), B<serverAuth>
295 (SSL server use) and B<emailProtection> (S/MIME email) are used.
296 Other OpenSSL applications may define additional uses.
298 =item B<-addreject arg>
300 adds a prohibited use. It accepts the same values as the B<-addtrust>
305 this option performs tests on the certificate extensions and outputs
306 the results. For a more complete description see the B<CERTIFICATE
311 =head2 SIGNING OPTIONS
313 The B<x509> utility can be used to sign certificates and requests: it
314 can thus behave like a "mini CA".
318 =item B<-signkey filename>
320 this option causes the input file to be self signed using the supplied
323 If the input file is a certificate it sets the issuer name to the
324 subject name (i.e. makes it self signed) changes the public key to the
325 supplied value and changes the start and end dates. The start date is
326 set to the current time and the end date is set to a value determined
327 by the B<-days> option. Any certificate extensions are retained unless
328 the B<-clrext> option is supplied.
330 If the input is a certificate request then a self signed certificate
331 is created using the supplied private key using the subject name in
336 the key password source. For more information about the format of B<arg>
337 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
341 delete any extensions from a certificate. This option is used when a
342 certificate is being created from another certificate (for example with
343 the B<-signkey> or the B<-CA> options). Normally all extensions are
346 =item B<-keyform PEM|DER>
348 specifies the format (DER or PEM) of the private key file used in the
353 specifies the number of days to make a certificate valid for. The default
358 converts a certificate into a certificate request. The B<-signkey> option
359 is used to pass the required private key.
363 by default a certificate is expected on input. With this option a
364 certificate request is expected instead.
366 =item B<-set_serial n>
368 specifies the serial number to use. This option can be used with either
369 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
370 option the serial number file (as specified by the B<-CAserial> or
371 B<-CAcreateserial> options) is not used.
373 The serial number can be decimal or hex (if preceded by B<0x>). Negative
374 serial numbers can also be specified but their use is not recommended.
376 =item B<-CA filename>
378 specifies the CA certificate to be used for signing. When this option is
379 present B<x509> behaves like a "mini CA". The input file is signed by this
380 CA using this option: that is its issuer name is set to the subject name
381 of the CA and it is digitally signed using the CAs private key.
383 This option is normally combined with the B<-req> option. Without the
384 B<-req> option the input is a certificate which must be self signed.
386 =item B<-CAkey filename>
388 sets the CA private key to sign a certificate with. If this option is
389 not specified then it is assumed that the CA private key is present in
390 the CA certificate file.
392 =item B<-CAserial filename>
394 sets the CA serial number file to use.
396 When the B<-CA> option is used to sign a certificate it uses a serial
397 number specified in a file. This file consist of one line containing
398 an even number of hex digits with the serial number to use. After each
399 use the serial number is incremented and written out to the file again.
401 The default filename consists of the CA certificate file base name with
402 ".srl" appended. For example if the CA certificate file is called
403 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
405 =item B<-CAcreateserial>
407 with this option the CA serial number file is created if it does not exist:
408 it will contain the serial number "02" and the certificate being signed will
409 have the 1 as its serial number. Normally if the B<-CA> option is specified
410 and the serial number file does not exist it is an error.
412 =item B<-extfile filename>
414 file containing certificate extensions to use. If not specified then
415 no extensions are added to the certificate.
417 =item B<-extensions section>
419 the section to add certificate extensions from. If this option is not
420 specified then the extensions should either be contained in the unnamed
421 (default) section or the default section should contain a variable called
422 "extensions" which contains the section to use. See the
423 L<x509v3_config(5)|x509v3_config(5)> manual page for details of the
424 extension section format.
426 =item B<-force_pubkey key>
428 when a certificate is created set its public key to B<key> instead of the
429 key in the certificate or certificate request. This option is useful for
430 creating certificates where the algorithm can't normally sign requests, for
433 The format or B<key> can be specified using the B<-keyform> option.
439 The B<nameopt> command line switch determines how the subject and issuer
440 names are displayed. If no B<nameopt> switch is present the default "oneline"
441 format is used which is compatible with previous versions of OpenSSL.
442 Each option is described in detail below, all options can be preceded by
443 a B<-> to turn the option off. Only the first four will normally be used.
449 use the old format. This is equivalent to specifying no name options at all.
453 displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
454 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
455 B<sep_comma_plus>, B<dn_rev> and B<sname>.
459 a oneline format which is more readable than RFC2253. It is equivalent to
460 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
461 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
466 a multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
467 B<space_eq>, B<lname> and B<align>.
471 escape the "special" characters required by RFC2253 in a field That is
472 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
473 and a space character at the beginning or end of a string.
477 escape control characters. That is those with ASCII values less than
478 0x20 (space) and the delete (0x7f) character. They are escaped using the
479 RFC2253 \XX notation (where XX are two hex digits representing the
484 escape characters with the MSB set, that is with ASCII values larger than
489 escapes some characters by surrounding the whole string with B<"> characters,
490 without the option all escaping is done with the B<\> character.
494 convert all strings to UTF8 format first. This is required by RFC2253. If
495 you are lucky enough to have a UTF8 compatible terminal then the use
496 of this option (and B<not> setting B<esc_msb>) may result in the correct
497 display of multibyte (international) characters. Is this option is not
498 present then multibyte characters larger than 0xff will be represented
499 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
500 Also if this option is off any UTF8Strings will be converted to their
501 character form first.
505 this option does not attempt to interpret multibyte characters in any
506 way. That is their content octets are merely dumped as though one octet
507 represents each character. This is useful for diagnostic purposes but
508 will result in rather odd looking output.
512 show the type of the ASN1 character string. The type precedes the
513 field contents. For example "BMPSTRING: Hello World".
517 when this option is set any fields that need to be hexdumped will
518 be dumped using the DER encoding of the field. Otherwise just the
519 content octets will be displayed. Both options use the RFC2253
524 dump non character string types (for example OCTET STRING) if this
525 option is not set then non character string types will be displayed
526 as though each content octet represents a single character.
530 dump all fields. This option when used with B<dump_der> allows the
531 DER encoding of the structure to be unambiguously determined.
533 =item B<dump_unknown>
535 dump any field whose OID is not recognised by OpenSSL.
537 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
540 these options determine the field separators. The first character is
541 between RDNs and the second between multiple AVAs (multiple AVAs are
542 very rare and their use is discouraged). The options ending in
543 "space" additionally place a space after the separator to make it
544 more readable. The B<sep_multiline> uses a linefeed character for
545 the RDN separator and a spaced B<+> for the AVA separator. It also
546 indents the fields by four characters. If no field separator is specified
547 then B<sep_comma_plus_space> is used by default.
551 reverse the fields of the DN. This is required by RFC2253. As a side
552 effect this also reverses the order of multiple AVAs but this is
555 =item B<nofname>, B<sname>, B<lname>, B<oid>
557 these options alter how the field name is displayed. B<nofname> does
558 not display the field at all. B<sname> uses the "short name" form
559 (CN for commonName for example). B<lname> uses the long form.
560 B<oid> represents the OID in numerical form and is useful for
565 align field values for a more readable output. Only usable with
570 places spaces round the B<=> character which follows the field
577 As well as customising the name output format, it is also possible to
578 customise the actual fields printed using the B<certopt> options when
579 the B<text> option is present. The default behaviour is to print all fields.
585 use the old format. This is equivalent to specifying no output options at all.
589 don't print header information: that is the lines saying "Certificate" and "Data".
593 don't print out the version number.
597 don't print out the serial number.
601 don't print out the signature algorithm used.
605 don't print the validity, that is the B<notBefore> and B<notAfter> fields.
609 don't print out the subject name.
613 don't print out the issuer name.
617 don't print out the public key.
621 don't give a hexadecimal dump of the certificate signature.
625 don't print out certificate trust information.
627 =item B<no_extensions>
629 don't print out any X509V3 extensions.
633 retain default extension behaviour: attempt to print out unsupported certificate extensions.
637 print an error message for unsupported certificate extensions.
641 ASN1 parse unsupported extensions.
645 hex dump unsupported extensions.
649 the value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
650 B<no_header>, and B<no_version>.
656 Note: in these examples the '\' means the example should be all on one
659 Display the contents of a certificate:
661 openssl x509 -in cert.pem -noout -text
663 Display the certificate serial number:
665 openssl x509 -in cert.pem -noout -serial
667 Display the certificate subject name:
669 openssl x509 -in cert.pem -noout -subject
671 Display the certificate subject name in RFC2253 form:
673 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
675 Display the certificate subject name in oneline form on a terminal
678 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
680 Display the certificate SHA1 fingerprint:
682 openssl x509 -sha1 -in cert.pem -noout -fingerprint
684 Convert a certificate from PEM to DER format:
686 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
688 Convert a certificate to a certificate request:
690 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
692 Convert a certificate request into a self signed certificate using
695 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
696 -signkey key.pem -out cacert.pem
698 Sign a certificate request using the CA certificate above and add user
699 certificate extensions:
701 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
702 -CA cacert.pem -CAkey key.pem -CAcreateserial
705 Set a certificate to be trusted for SSL client use and change set its alias to
708 openssl x509 -in cert.pem -addtrust clientAuth \
709 -setalias "Steve's Class 1 CA" -out trust.pem
713 The PEM format uses the header and footer lines:
715 -----BEGIN CERTIFICATE-----
716 -----END CERTIFICATE-----
718 it will also handle files containing:
720 -----BEGIN X509 CERTIFICATE-----
721 -----END X509 CERTIFICATE-----
723 Trusted certificates have the lines
725 -----BEGIN TRUSTED CERTIFICATE-----
726 -----END TRUSTED CERTIFICATE-----
728 The conversion to UTF8 format used with the name options assumes that
729 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
730 and MSIE do this as do many certificates. So although this is incorrect
731 it is more likely to display the majority of certificates correctly.
733 The B<-email> option searches the subject name and the subject alternative
734 name extension. Only unique email addresses will be printed out: it will
735 not print the same address more than once.
737 =head1 CERTIFICATE EXTENSIONS
739 The B<-purpose> option checks the certificate extensions and determines
740 what the certificate can be used for. The actual checks done are rather
741 complex and include various hacks and workarounds to handle broken
742 certificates and software.
744 The same code is used when verifying untrusted certificates in chains
745 so this section is useful if a chain is rejected by the verify code.
747 The basicConstraints extension CA flag is used to determine whether the
748 certificate can be used as a CA. If the CA flag is true then it is a CA,
749 if the CA flag is false then it is not a CA. B<All> CAs should have the
752 If the basicConstraints extension is absent then the certificate is
753 considered to be a "possible CA" other extensions are checked according
754 to the intended use of the certificate. A warning is given in this case
755 because the certificate should really not be regarded as a CA: however
756 it is allowed to be a CA to work around some broken software.
758 If the certificate is a V1 certificate (and thus has no extensions) and
759 it is self signed it is also assumed to be a CA but a warning is again
760 given: this is to work around the problem of Verisign roots which are V1
761 self signed certificates.
763 If the keyUsage extension is present then additional restraints are
764 made on the uses of the certificate. A CA certificate B<must> have the
765 keyCertSign bit set if the keyUsage extension is present.
767 The extended key usage extension places additional restrictions on the
768 certificate uses. If this extension is present (whether critical or not)
769 the key can only be used for the purposes specified.
771 A complete description of each test is given below. The comments about
772 basicConstraints and keyUsage and V1 certificates above apply to B<all>
780 The extended key usage extension must be absent or include the "web client
781 authentication" OID. keyUsage must be absent or it must have the
782 digitalSignature bit set. Netscape certificate type must be absent or it must
783 have the SSL client bit set.
785 =item B<SSL Client CA>
787 The extended key usage extension must be absent or include the "web client
788 authentication" OID. Netscape certificate type must be absent or it must have
789 the SSL CA bit set: this is used as a work around if the basicConstraints
794 The extended key usage extension must be absent or include the "web server
795 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
796 must have the digitalSignature, the keyEncipherment set or both bits set.
797 Netscape certificate type must be absent or have the SSL server bit set.
799 =item B<SSL Server CA>
801 The extended key usage extension must be absent or include the "web server
802 authentication" and/or one of the SGC OIDs. Netscape certificate type must
803 be absent or the SSL CA bit must be set: this is used as a work around if the
804 basicConstraints extension is absent.
806 =item B<Netscape SSL Server>
808 For Netscape SSL clients to connect to an SSL server it must have the
809 keyEncipherment bit set if the keyUsage extension is present. This isn't
810 always valid because some cipher suites use the key for digital signing.
811 Otherwise it is the same as a normal SSL server.
813 =item B<Common S/MIME Client Tests>
815 The extended key usage extension must be absent or include the "email
816 protection" OID. Netscape certificate type must be absent or should have the
817 S/MIME bit set. If the S/MIME bit is not set in netscape certificate type
818 then the SSL client bit is tolerated as an alternative but a warning is shown:
819 this is because some Verisign certificates don't set the S/MIME bit.
821 =item B<S/MIME Signing>
823 In addition to the common S/MIME client tests the digitalSignature bit must
824 be set if the keyUsage extension is present.
826 =item B<S/MIME Encryption>
828 In addition to the common S/MIME tests the keyEncipherment bit must be set
829 if the keyUsage extension is present.
833 The extended key usage extension must be absent or include the "email
834 protection" OID. Netscape certificate type must be absent or must have the
835 S/MIME CA bit set: this is used as a work around if the basicConstraints
840 The keyUsage extension must be absent or it must have the CRL signing bit
843 =item B<CRL Signing CA>
845 The normal CA tests apply. Except in this case the basicConstraints extension
852 Extensions in certificates are not transferred to certificate requests and
855 It is possible to produce invalid certificates or requests by specifying the
856 wrong private key or using inconsistent options in some cases: these should
859 There should be options to explicitly set such things as start and end
860 dates rather than an offset from the current time.
862 The code to implement the verify behaviour described in the B<TRUST SETTINGS>
863 is currently being developed. It thus describes the intended behaviour rather
864 than the current behaviour. It is hoped that it will represent reality in
865 OpenSSL 0.9.5 and later.
869 L<req(1)|req(1)>, L<ca(1)|ca(1)>, L<genrsa(1)|genrsa(1)>,
870 L<gendsa(1)|gendsa(1)>, L<verify(1)|verify(1)>,
871 L<x509v3_config(5)|x509v3_config(5)>
875 Before OpenSSL 0.9.8, the default digest for RSA keys was MD5.
877 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
878 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
879 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
880 canonical version of the DN using SHA1. This means that any directories using
881 the old form must have their links rebuilt using B<c_rehash> or similar.