6 x509 - Certificate display and signing utility
11 [B<-inform DER|PEM|NET>]
12 [B<-outform DER|PEM|NET>]
15 [B<-CAkeyform DER|PEM>]
42 [B<-signkey filename>]
48 [B<-CAserial filename>]
51 [B<-md2|-md5|-sha1|-mdc2>]
53 [B<-extfile filename>]
54 [B<-extensions section>]
59 The B<x509> command is a multi purpose certificate utility. It can be
60 used to display certificate information, convert certificates to
61 various forms, sign certificate requests like a "mini CA" or edit
62 certificate trust settings.
64 Since there are a large number of options they will split up into
69 =head2 INPUT, OUTPUT AND GENERAL PURPOSE OPTIONS
73 =item B<-inform DER|PEM|NET>
75 This specifies the input format normally the command will expect an X509
76 certificate but this can change if other options such as B<-req> are
77 present. The DER format is the DER encoding of the certificate and PEM
78 is the base64 encoding of the DER encoding with header and footer lines
79 added. The NET option is an obscure Netscape server format that is now
82 =item B<-outform DER|PEM|NET>
84 This specifies the output format, the options have the same meaning as the
89 This specifies the input filename to read a certificate from or standard input
90 if this option is not specified.
92 =item B<-out filename>
94 This specifies the output filename to write to or standard output by
97 =item B<-md2|-md5|-sha1|-mdc2>
99 the digest to use. This affects any signing or display option that uses a message
100 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options. If not
101 specified then SHA1 is used. If the key being used to sign with is a DSA key
102 then this option has no effect: SHA1 is always used with DSA keys.
106 specifying an engine (by it's unique B<id> string) will cause B<req>
107 to attempt to obtain a functional reference to the specified engine,
108 thus initialising it if needed. The engine will then be set as the default
109 for all available algorithms.
113 =head2 DISPLAY OPTIONS
115 Note: the B<-alias> and B<-purpose> options are also display options
116 but are described in the B<TRUST SETTINGS> section.
122 prints out the certificate in text form. Full details are output including the
123 public key, signature algorithms, issuer and subject names, serial number
124 any extensions present and any trust settings.
126 =item B<-certopt option>
128 customise the output format used with B<-text>. The B<option> argument can be
129 a single option or multiple options separated by commas. The B<-certopt> switch
130 may be also be used more than once to set multiple options. See the B<TEXT OPTIONS>
131 section for more information.
135 this option prevents output of the encoded version of the request.
139 this option prints out the value of the modulus of the public key
140 contained in the certificate.
144 outputs the certificate serial number.
146 =item B<-subject_hash>
148 outputs the "hash" of the certificate subject name. This is used in OpenSSL to
149 form an index to allow certificates in a directory to be looked up by subject
152 =item B<-issuer_hash>
154 outputs the "hash" of the certificate issuer name.
158 synonym for "-hash" for backward compatibility reasons.
162 outputs the subject name.
166 outputs the issuer name.
168 =item B<-nameopt option>
170 option which determines how the subject or issuer names are displayed. The
171 B<option> argument can be a single option or multiple options separated by
172 commas. Alternatively the B<-nameopt> switch may be used more than once to
173 set multiple options. See the B<NAME OPTIONS> section for more information.
177 outputs the email address(es) if any.
181 prints out the start date of the certificate, that is the notBefore date.
185 prints out the expiry date of the certificate, that is the notAfter date.
189 prints out the start and expiry dates of a certificate.
191 =item B<-fingerprint>
193 prints out the digest of the DER encoded version of the whole certificate
194 (see digest options).
198 this outputs the certificate in the form of a C source file.
202 =head2 TRUST SETTINGS
204 Please note these options are currently experimental and may well change.
206 A B<trusted certificate> is an ordinary certificate which has several
207 additional pieces of information attached to it such as the permitted
208 and prohibited uses of the certificate and an "alias".
210 Normally when a certificate is being verified at least one certificate
211 must be "trusted". By default a trusted certificate must be stored
212 locally and must be a root CA: any certificate chain ending in this CA
213 is then usable for any purpose.
215 Trust settings currently are only used with a root CA. They allow a finer
216 control over the purposes the root CA can be used for. For example a CA
217 may be trusted for SSL client but not SSL server use.
219 See the description of the B<verify> utility for more information on the
220 meaning of trust settings.
222 Future versions of OpenSSL will recognize trust settings on any
223 certificate: not just root CAs.
230 this causes B<x509> to output a B<trusted> certificate. An ordinary
231 or trusted certificate can be input but by default an ordinary
232 certificate is output and any trust settings are discarded. With the
233 B<-trustout> option a trusted certificate is output. A trusted
234 certificate is automatically output if any trust settings are modified.
236 =item B<-setalias arg>
238 sets the alias of the certificate. This will allow the certificate
239 to be referred to using a nickname for example "Steve's Certificate".
243 outputs the certificate alias, if any.
247 clears all the permitted or trusted uses of the certificate.
251 clears all the prohibited or rejected uses of the certificate.
253 =item B<-addtrust arg>
255 adds a trusted certificate use. Any object name can be used here
256 but currently only B<clientAuth> (SSL client use), B<serverAuth>
257 (SSL server use) and B<emailProtection> (S/MIME email) are used.
258 Other OpenSSL applications may define additional uses.
260 =item B<-addreject arg>
262 adds a prohibited use. It accepts the same values as the B<-addtrust>
267 this option performs tests on the certificate extensions and outputs
268 the results. For a more complete description see the B<CERTIFICATE
273 =head2 SIGNING OPTIONS
275 The B<x509> utility can be used to sign certificates and requests: it
276 can thus behave like a "mini CA".
280 =item B<-signkey filename>
282 this option causes the input file to be self signed using the supplied
285 If the input file is a certificate it sets the issuer name to the
286 subject name (i.e. makes it self signed) changes the public key to the
287 supplied value and changes the start and end dates. The start date is
288 set to the current time and the end date is set to a value determined
289 by the B<-days> option. Any certificate extensions are retained unless
290 the B<-clrext> option is supplied.
292 If the input is a certificate request then a self signed certificate
293 is created using the supplied private key using the subject name in
298 delete any extensions from a certificate. This option is used when a
299 certificate is being created from another certificate (for example with
300 the B<-signkey> or the B<-CA> options). Normally all extensions are
303 =item B<-keyform PEM|DER>
305 specifies the format (DER or PEM) of the private key file used in the
310 specifies the number of days to make a certificate valid for. The default
315 converts a certificate into a certificate request. The B<-signkey> option
316 is used to pass the required private key.
320 by default a certificate is expected on input. With this option a
321 certificate request is expected instead.
323 =item B<-set_serial n>
325 specifies the serial number to use. This option can be used with either
326 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
327 option the serial number file (as specified by the B<-CAserial> or
328 B<-CAcreateserial> options) is not used.
330 The serial number can be decimal or hex (if preceded by B<0x>). Negative
331 serial numbers can also be specified but their use is not recommended.
333 =item B<-CA filename>
335 specifies the CA certificate to be used for signing. When this option is
336 present B<x509> behaves like a "mini CA". The input file is signed by this
337 CA using this option: that is its issuer name is set to the subject name
338 of the CA and it is digitally signed using the CAs private key.
340 This option is normally combined with the B<-req> option. Without the
341 B<-req> option the input is a certificate which must be self signed.
343 =item B<-CAkey filename>
345 sets the CA private key to sign a certificate with. If this option is
346 not specified then it is assumed that the CA private key is present in
347 the CA certificate file.
349 =item B<-CAserial filename>
351 sets the CA serial number file to use.
353 When the B<-CA> option is used to sign a certificate it uses a serial
354 number specified in a file. This file consist of one line containing
355 an even number of hex digits with the serial number to use. After each
356 use the serial number is incremented and written out to the file again.
358 The default filename consists of the CA certificate file base name with
359 ".srl" appended. For example if the CA certificate file is called
360 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
362 =item B<-CAcreateserial>
364 with this option the CA serial number file is created if it does not exist:
365 it will contain the serial number "02" and the certificate being signed will
366 have the 1 as its serial number. Normally if the B<-CA> option is specified
367 and the serial number file does not exist it is an error.
369 =item B<-extfile filename>
371 file containing certificate extensions to use. If not specified then
372 no extensions are added to the certificate.
374 =item B<-extensions section>
376 the section to add certificate extensions from. If this option is not
377 specified then the extensions should either be contained in the unnamed
378 (default) section or the default section should contain a variable called
379 "extensions" which contains the section to use. See the
380 L<x509v3_config(5)|x509v3_config(5)> manual page for details of the
381 extension section format.
387 The B<nameopt> command line switch determines how the subject and issuer
388 names are displayed. If no B<nameopt> switch is present the default "oneline"
389 format is used which is compatible with previous versions of OpenSSL.
390 Each option is described in detail below, all options can be preceded by
391 a B<-> to turn the option off. Only the first four will normally be used.
397 use the old format. This is equivalent to specifying no name options at all.
401 displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
402 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
403 B<sep_comma_plus>, B<dn_rev> and B<sname>.
407 a oneline format which is more readable than RFC2253. It is equivalent to
408 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
409 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
414 a multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
415 B<space_eq>, B<lname> and B<align>.
419 escape the "special" characters required by RFC2253 in a field That is
420 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
421 and a space character at the beginning or end of a string.
425 escape control characters. That is those with ASCII values less than
426 0x20 (space) and the delete (0x7f) character. They are escaped using the
427 RFC2253 \XX notation (where XX are two hex digits representing the
432 escape characters with the MSB set, that is with ASCII values larger than
437 escapes some characters by surrounding the whole string with B<"> characters,
438 without the option all escaping is done with the B<\> character.
442 convert all strings to UTF8 format first. This is required by RFC2253. If
443 you are lucky enough to have a UTF8 compatible terminal then the use
444 of this option (and B<not> setting B<esc_msb>) may result in the correct
445 display of multibyte (international) characters. Is this option is not
446 present then multibyte characters larger than 0xff will be represented
447 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
448 Also if this option is off any UTF8Strings will be converted to their
449 character form first.
453 this option does not attempt to interpret multibyte characters in any
454 way. That is their content octets are merely dumped as though one octet
455 represents each character. This is useful for diagnostic purposes but
456 will result in rather odd looking output.
460 show the type of the ASN1 character string. The type precedes the
461 field contents. For example "BMPSTRING: Hello World".
465 when this option is set any fields that need to be hexdumped will
466 be dumped using the DER encoding of the field. Otherwise just the
467 content octets will be displayed. Both options use the RFC2253
472 dump non character string types (for example OCTET STRING) if this
473 option is not set then non character string types will be displayed
474 as though each content octet represents a single character.
478 dump all fields. This option when used with B<dump_der> allows the
479 DER encoding of the structure to be unambiguously determined.
481 =item B<dump_unknown>
483 dump any field whose OID is not recognised by OpenSSL.
485 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
488 these options determine the field separators. The first character is
489 between RDNs and the second between multiple AVAs (multiple AVAs are
490 very rare and their use is discouraged). The options ending in
491 "space" additionally place a space after the separator to make it
492 more readable. The B<sep_multiline> uses a linefeed character for
493 the RDN separator and a spaced B<+> for the AVA separator. It also
494 indents the fields by four characters.
498 reverse the fields of the DN. This is required by RFC2253. As a side
499 effect this also reverses the order of multiple AVAs but this is
502 =item B<nofname>, B<sname>, B<lname>, B<oid>
504 these options alter how the field name is displayed. B<nofname> does
505 not display the field at all. B<sname> uses the "short name" form
506 (CN for commonName for example). B<lname> uses the long form.
507 B<oid> represents the OID in numerical form and is useful for
512 align field values for a more readable output. Only usable with
517 places spaces round the B<=> character which follows the field
524 As well as customising the name output format, it is also possible to
525 customise the actual fields printed using the B<certopt> options when
526 the B<text> option is present. The default behaviour is to print all fields.
532 use the old format. This is equivalent to specifying no output options at all.
536 don't print header information: that is the lines saying "Certificate" and "Data".
540 don't print out the version number.
544 don't print out the serial number.
548 don't print out the signature algorithm used.
552 don't print the validity, that is the B<notBefore> and B<notAfter> fields.
556 don't print out the subject name.
560 don't print out the issuer name.
564 don't print out the public key.
568 don't give a hexadecimal dump of the certificate signature.
572 don't print out certificate trust information.
574 =item B<no_extensions>
576 don't print out any X509V3 extensions.
580 retain default extension behaviour: attempt to print out unsupported certificate extensions.
584 print an error message for unsupported certificate extensions.
588 ASN1 parse unsupported extensions.
592 hex dump unsupported extensions.
596 the value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>, B<no_header>,
597 B<no_version>, B<no_sigdump> and B<no_signame>.
603 Note: in these examples the '\' means the example should be all on one
606 Display the contents of a certificate:
608 openssl x509 -in cert.pem -noout -text
610 Display the certificate serial number:
612 openssl x509 -in cert.pem -noout -serial
614 Display the certificate subject name:
616 openssl x509 -in cert.pem -noout -subject
618 Display the certificate subject name in RFC2253 form:
620 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
622 Display the certificate subject name in oneline form on a terminal
625 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
627 Display the certificate MD5 fingerprint:
629 openssl x509 -in cert.pem -noout -fingerprint
631 Display the certificate SHA1 fingerprint:
633 openssl x509 -sha1 -in cert.pem -noout -fingerprint
635 Convert a certificate from PEM to DER format:
637 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
639 Convert a certificate to a certificate request:
641 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
643 Convert a certificate request into a self signed certificate using
646 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
647 -signkey key.pem -out cacert.pem
649 Sign a certificate request using the CA certificate above and add user
650 certificate extensions:
652 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
653 -CA cacert.pem -CAkey key.pem -CAcreateserial
656 Set a certificate to be trusted for SSL client use and change set its alias to
659 openssl x509 -in cert.pem -addtrust clientAuth \
660 -setalias "Steve's Class 1 CA" -out trust.pem
664 The PEM format uses the header and footer lines:
666 -----BEGIN CERTIFICATE-----
667 -----END CERTIFICATE-----
669 it will also handle files containing:
671 -----BEGIN X509 CERTIFICATE-----
672 -----END X509 CERTIFICATE-----
674 Trusted certificates have the lines
676 -----BEGIN TRUSTED CERTIFICATE-----
677 -----END TRUSTED CERTIFICATE-----
679 The conversion to UTF8 format used with the name options assumes that
680 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
681 and MSIE do this as do many certificates. So although this is incorrect
682 it is more likely to display the majority of certificates correctly.
684 The B<-fingerprint> option takes the digest of the DER encoded certificate.
685 This is commonly called a "fingerprint". Because of the nature of message
686 digests the fingerprint of a certificate is unique to that certificate and
687 two certificates with the same fingerprint can be considered to be the same.
689 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
691 The B<-email> option searches the subject name and the subject alternative
692 name extension. Only unique email addresses will be printed out: it will
693 not print the same address more than once.
695 =head1 CERTIFICATE EXTENSIONS
697 The B<-purpose> option checks the certificate extensions and determines
698 what the certificate can be used for. The actual checks done are rather
699 complex and include various hacks and workarounds to handle broken
700 certificates and software.
702 The same code is used when verifying untrusted certificates in chains
703 so this section is useful if a chain is rejected by the verify code.
705 The basicConstraints extension CA flag is used to determine whether the
706 certificate can be used as a CA. If the CA flag is true then it is a CA,
707 if the CA flag is false then it is not a CA. B<All> CAs should have the
710 If the basicConstraints extension is absent then the certificate is
711 considered to be a "possible CA" other extensions are checked according
712 to the intended use of the certificate. A warning is given in this case
713 because the certificate should really not be regarded as a CA: however
714 it is allowed to be a CA to work around some broken software.
716 If the certificate is a V1 certificate (and thus has no extensions) and
717 it is self signed it is also assumed to be a CA but a warning is again
718 given: this is to work around the problem of Verisign roots which are V1
719 self signed certificates.
721 If the keyUsage extension is present then additional restraints are
722 made on the uses of the certificate. A CA certificate B<must> have the
723 keyCertSign bit set if the keyUsage extension is present.
725 The extended key usage extension places additional restrictions on the
726 certificate uses. If this extension is present (whether critical or not)
727 the key can only be used for the purposes specified.
729 A complete description of each test is given below. The comments about
730 basicConstraints and keyUsage and V1 certificates above apply to B<all>
738 The extended key usage extension must be absent or include the "web client
739 authentication" OID. keyUsage must be absent or it must have the
740 digitalSignature bit set. Netscape certificate type must be absent or it must
741 have the SSL client bit set.
743 =item B<SSL Client CA>
745 The extended key usage extension must be absent or include the "web client
746 authentication" OID. Netscape certificate type must be absent or it must have
747 the SSL CA bit set: this is used as a work around if the basicConstraints
752 The extended key usage extension must be absent or include the "web server
753 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
754 must have the digitalSignature, the keyEncipherment set or both bits set.
755 Netscape certificate type must be absent or have the SSL server bit set.
757 =item B<SSL Server CA>
759 The extended key usage extension must be absent or include the "web server
760 authentication" and/or one of the SGC OIDs. Netscape certificate type must
761 be absent or the SSL CA bit must be set: this is used as a work around if the
762 basicConstraints extension is absent.
764 =item B<Netscape SSL Server>
766 For Netscape SSL clients to connect to an SSL server it must have the
767 keyEncipherment bit set if the keyUsage extension is present. This isn't
768 always valid because some cipher suites use the key for digital signing.
769 Otherwise it is the same as a normal SSL server.
771 =item B<Common S/MIME Client Tests>
773 The extended key usage extension must be absent or include the "email
774 protection" OID. Netscape certificate type must be absent or should have the
775 S/MIME bit set. If the S/MIME bit is not set in netscape certificate type
776 then the SSL client bit is tolerated as an alternative but a warning is shown:
777 this is because some Verisign certificates don't set the S/MIME bit.
779 =item B<S/MIME Signing>
781 In addition to the common S/MIME client tests the digitalSignature bit must
782 be set if the keyUsage extension is present.
784 =item B<S/MIME Encryption>
786 In addition to the common S/MIME tests the keyEncipherment bit must be set
787 if the keyUsage extension is present.
791 The extended key usage extension must be absent or include the "email
792 protection" OID. Netscape certificate type must be absent or must have the
793 S/MIME CA bit set: this is used as a work around if the basicConstraints
798 The keyUsage extension must be absent or it must have the CRL signing bit
801 =item B<CRL Signing CA>
803 The normal CA tests apply. Except in this case the basicConstraints extension
810 Extensions in certificates are not transferred to certificate requests and
813 It is possible to produce invalid certificates or requests by specifying the
814 wrong private key or using inconsistent options in some cases: these should
817 There should be options to explicitly set such things as start and end
818 dates rather than an offset from the current time.
820 The code to implement the verify behaviour described in the B<TRUST SETTINGS>
821 is currently being developed. It thus describes the intended behaviour rather
822 than the current behaviour. It is hoped that it will represent reality in
823 OpenSSL 0.9.5 and later.
827 L<req(1)|req(1)>, L<ca(1)|ca(1)>, L<genrsa(1)|genrsa(1)>,
828 L<gendsa(1)|gendsa(1)>, L<verify(1)|verify(1)>,
829 L<x509v3_config(5)|x509v3_config(5)>
833 Before OpenSSL 0.9.8, the default digest for RSA keys was MD5.