6 x509 - Certificate display and signing utility
11 [B<-inform DER|PEM|NET>]
12 [B<-outform DER|PEM|NET>]
15 [B<-CAkeyform DER|PEM>]
44 [B<-signkey filename>]
51 [B<-CAserial filename>]
55 [B<-md2|-md5|-sha1|-mdc2>]
57 [B<-extfile filename>]
58 [B<-extensions section>]
63 The B<x509> command is a multi purpose certificate utility. It can be
64 used to display certificate information, convert certificates to
65 various forms, sign certificate requests like a "mini CA" or edit
66 certificate trust settings.
68 Since there are a large number of options they will split up into
73 =head2 INPUT, OUTPUT AND GENERAL PURPOSE OPTIONS
77 =item B<-inform DER|PEM|NET>
79 This specifies the input format normally the command will expect an X509
80 certificate but this can change if other options such as B<-req> are
81 present. The DER format is the DER encoding of the certificate and PEM
82 is the base64 encoding of the DER encoding with header and footer lines
83 added. The NET option is an obscure Netscape server format that is now
86 =item B<-outform DER|PEM|NET>
88 This specifies the output format, the options have the same meaning as the
93 This specifies the input filename to read a certificate from or standard input
94 if this option is not specified.
96 =item B<-out filename>
98 This specifies the output filename to write to or standard output by
101 =item B<-md2|-md5|-sha1|-mdc2>
103 the digest to use. This affects any signing or display option that uses a message
104 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options. If not
105 specified then SHA1 is used. If the key being used to sign with is a DSA key
106 then this option has no effect: SHA1 is always used with DSA keys.
110 specifying an engine (by it's unique B<id> string) will cause B<req>
111 to attempt to obtain a functional reference to the specified engine,
112 thus initialising it if needed. The engine will then be set as the default
113 for all available algorithms.
117 =head2 DISPLAY OPTIONS
119 Note: the B<-alias> and B<-purpose> options are also display options
120 but are described in the B<TRUST SETTINGS> section.
126 prints out the certificate in text form. Full details are output including the
127 public key, signature algorithms, issuer and subject names, serial number
128 any extensions present and any trust settings.
130 =item B<-certopt option>
132 customise the output format used with B<-text>. The B<option> argument can be
133 a single option or multiple options separated by commas. The B<-certopt> switch
134 may be also be used more than once to set multiple options. See the B<TEXT OPTIONS>
135 section for more information.
139 this option prevents output of the encoded version of the request.
143 this option prints out the value of the modulus of the public key
144 contained in the certificate.
148 outputs the certificate serial number.
150 =item B<-subject_hash>
152 outputs the "hash" of the certificate subject name. This is used in OpenSSL to
153 form an index to allow certificates in a directory to be looked up by subject
156 =item B<-issuer_hash>
158 outputs the "hash" of the certificate issuer name.
162 outputs the OCSP hash values for the subject name and public key.
166 synonym for "-subject_hash" for backward compatibility reasons.
170 outputs the subject name.
174 outputs the issuer name.
176 =item B<-nameopt option>
178 option which determines how the subject or issuer names are displayed. The
179 B<option> argument can be a single option or multiple options separated by
180 commas. Alternatively the B<-nameopt> switch may be used more than once to
181 set multiple options. See the B<NAME OPTIONS> section for more information.
185 outputs the email address(es) if any.
189 prints out the start date of the certificate, that is the notBefore date.
193 prints out the expiry date of the certificate, that is the notAfter date.
197 prints out the start and expiry dates of a certificate.
199 =item B<-checkend arg>
201 checks if the certificate expires within the next B<arg> seconds and exits
202 non-zero if yes it will expire or zero if not.
204 =item B<-fingerprint>
206 prints out the digest of the DER encoded version of the whole certificate
207 (see digest options).
211 this outputs the certificate in the form of a C source file.
215 =head2 TRUST SETTINGS
217 Please note these options are currently experimental and may well change.
219 A B<trusted certificate> is an ordinary certificate which has several
220 additional pieces of information attached to it such as the permitted
221 and prohibited uses of the certificate and an "alias".
223 Normally when a certificate is being verified at least one certificate
224 must be "trusted". By default a trusted certificate must be stored
225 locally and must be a root CA: any certificate chain ending in this CA
226 is then usable for any purpose.
228 Trust settings currently are only used with a root CA. They allow a finer
229 control over the purposes the root CA can be used for. For example a CA
230 may be trusted for SSL client but not SSL server use.
232 See the description of the B<verify> utility for more information on the
233 meaning of trust settings.
235 Future versions of OpenSSL will recognize trust settings on any
236 certificate: not just root CAs.
243 this causes B<x509> to output a B<trusted> certificate. An ordinary
244 or trusted certificate can be input but by default an ordinary
245 certificate is output and any trust settings are discarded. With the
246 B<-trustout> option a trusted certificate is output. A trusted
247 certificate is automatically output if any trust settings are modified.
249 =item B<-setalias arg>
251 sets the alias of the certificate. This will allow the certificate
252 to be referred to using a nickname for example "Steve's Certificate".
256 outputs the certificate alias, if any.
260 clears all the permitted or trusted uses of the certificate.
264 clears all the prohibited or rejected uses of the certificate.
266 =item B<-addtrust arg>
268 adds a trusted certificate use. Any object name can be used here
269 but currently only B<clientAuth> (SSL client use), B<serverAuth>
270 (SSL server use) and B<emailProtection> (S/MIME email) are used.
271 Other OpenSSL applications may define additional uses.
273 =item B<-addreject arg>
275 adds a prohibited use. It accepts the same values as the B<-addtrust>
280 this option performs tests on the certificate extensions and outputs
281 the results. For a more complete description see the B<CERTIFICATE
286 =head2 SIGNING OPTIONS
288 The B<x509> utility can be used to sign certificates and requests: it
289 can thus behave like a "mini CA".
293 =item B<-signkey filename>
295 this option causes the input file to be self signed using the supplied
298 If the input file is a certificate it sets the issuer name to the
299 subject name (i.e. makes it self signed) changes the public key to the
300 supplied value and changes the start and end dates. The start date is
301 set to the current time and the end date is set to a value determined
302 by the B<-days> option. Any certificate extensions are retained unless
303 the B<-clrext> option is supplied.
305 If the input is a certificate request then a self signed certificate
306 is created using the supplied private key using the subject name in
311 the key password source. For more information about the format of B<arg>
312 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
316 delete any extensions from a certificate. This option is used when a
317 certificate is being created from another certificate (for example with
318 the B<-signkey> or the B<-CA> options). Normally all extensions are
321 =item B<-keyform PEM|DER>
323 specifies the format (DER or PEM) of the private key file used in the
328 specifies the number of days to make a certificate valid for. The default
333 converts a certificate into a certificate request. The B<-signkey> option
334 is used to pass the required private key.
338 by default a certificate is expected on input. With this option a
339 certificate request is expected instead.
341 =item B<-set_serial n>
343 specifies the serial number to use. This option can be used with either
344 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
345 option the serial number file (as specified by the B<-CAserial> or
346 B<-CAcreateserial> options) is not used.
348 The serial number can be decimal or hex (if preceded by B<0x>). Negative
349 serial numbers can also be specified but their use is not recommended.
351 =item B<-CA filename>
353 specifies the CA certificate to be used for signing. When this option is
354 present B<x509> behaves like a "mini CA". The input file is signed by this
355 CA using this option: that is its issuer name is set to the subject name
356 of the CA and it is digitally signed using the CAs private key.
358 This option is normally combined with the B<-req> option. Without the
359 B<-req> option the input is a certificate which must be self signed.
361 =item B<-CAkey filename>
363 sets the CA private key to sign a certificate with. If this option is
364 not specified then it is assumed that the CA private key is present in
365 the CA certificate file.
367 =item B<-CAserial filename>
369 sets the CA serial number file to use.
371 When the B<-CA> option is used to sign a certificate it uses a serial
372 number specified in a file. This file consist of one line containing
373 an even number of hex digits with the serial number to use. After each
374 use the serial number is incremented and written out to the file again.
376 The default filename consists of the CA certificate file base name with
377 ".srl" appended. For example if the CA certificate file is called
378 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
380 =item B<-CAcreateserial>
382 with this option the CA serial number file is created if it does not exist:
383 it will contain the serial number "02" and the certificate being signed will
384 have the 1 as its serial number. Normally if the B<-CA> option is specified
385 and the serial number file does not exist it is an error.
387 =item B<-extfile filename>
389 file containing certificate extensions to use. If not specified then
390 no extensions are added to the certificate.
392 =item B<-extensions section>
394 the section to add certificate extensions from. If this option is not
395 specified then the extensions should either be contained in the unnamed
396 (default) section or the default section should contain a variable called
397 "extensions" which contains the section to use.
403 The B<nameopt> command line switch determines how the subject and issuer
404 names are displayed. If no B<nameopt> switch is present the default "oneline"
405 format is used which is compatible with previous versions of OpenSSL.
406 Each option is described in detail below, all options can be preceded by
407 a B<-> to turn the option off. Only the first four will normally be used.
413 use the old format. This is equivalent to specifying no name options at all.
417 displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
418 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
419 B<sep_comma_plus>, B<dn_rev> and B<sname>.
423 a oneline format which is more readable than RFC2253. It is equivalent to
424 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
425 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
430 a multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
431 B<space_eq>, B<lname> and B<align>.
435 escape the "special" characters required by RFC2253 in a field That is
436 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
437 and a space character at the beginning or end of a string.
441 escape control characters. That is those with ASCII values less than
442 0x20 (space) and the delete (0x7f) character. They are escaped using the
443 RFC2253 \XX notation (where XX are two hex digits representing the
448 escape characters with the MSB set, that is with ASCII values larger than
453 escapes some characters by surrounding the whole string with B<"> characters,
454 without the option all escaping is done with the B<\> character.
458 convert all strings to UTF8 format first. This is required by RFC2253. If
459 you are lucky enough to have a UTF8 compatible terminal then the use
460 of this option (and B<not> setting B<esc_msb>) may result in the correct
461 display of multibyte (international) characters. Is this option is not
462 present then multibyte characters larger than 0xff will be represented
463 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
464 Also if this option is off any UTF8Strings will be converted to their
465 character form first.
469 this option does not attempt to interpret multibyte characters in any
470 way. That is their content octets are merely dumped as though one octet
471 represents each character. This is useful for diagnostic purposes but
472 will result in rather odd looking output.
476 show the type of the ASN1 character string. The type precedes the
477 field contents. For example "BMPSTRING: Hello World".
481 when this option is set any fields that need to be hexdumped will
482 be dumped using the DER encoding of the field. Otherwise just the
483 content octets will be displayed. Both options use the RFC2253
488 dump non character string types (for example OCTET STRING) if this
489 option is not set then non character string types will be displayed
490 as though each content octet represents a single character.
494 dump all fields. This option when used with B<dump_der> allows the
495 DER encoding of the structure to be unambiguously determined.
497 =item B<dump_unknown>
499 dump any field whose OID is not recognised by OpenSSL.
501 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
504 these options determine the field separators. The first character is
505 between RDNs and the second between multiple AVAs (multiple AVAs are
506 very rare and their use is discouraged). The options ending in
507 "space" additionally place a space after the separator to make it
508 more readable. The B<sep_multiline> uses a linefeed character for
509 the RDN separator and a spaced B<+> for the AVA separator. It also
510 indents the fields by four characters.
514 reverse the fields of the DN. This is required by RFC2253. As a side
515 effect this also reverses the order of multiple AVAs but this is
518 =item B<nofname>, B<sname>, B<lname>, B<oid>
520 these options alter how the field name is displayed. B<nofname> does
521 not display the field at all. B<sname> uses the "short name" form
522 (CN for commonName for example). B<lname> uses the long form.
523 B<oid> represents the OID in numerical form and is useful for
528 align field values for a more readable output. Only usable with
533 places spaces round the B<=> character which follows the field
540 As well as customising the name output format, it is also possible to
541 customise the actual fields printed using the B<certopt> options when
542 the B<text> option is present. The default behaviour is to print all fields.
548 use the old format. This is equivalent to specifying no output options at all.
552 don't print header information: that is the lines saying "Certificate" and "Data".
556 don't print out the version number.
560 don't print out the serial number.
564 don't print out the signature algorithm used.
568 don't print the validity, that is the B<notBefore> and B<notAfter> fields.
572 don't print out the subject name.
576 don't print out the issuer name.
580 don't print out the public key.
584 don't give a hexadecimal dump of the certificate signature.
588 don't print out certificate trust information.
590 =item B<no_extensions>
592 don't print out any X509V3 extensions.
596 retain default extension behaviour: attempt to print out unsupported certificate extensions.
600 print an error message for unsupported certificate extensions.
604 ASN1 parse unsupported extensions.
608 hex dump unsupported extensions.
612 the value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>, B<no_header>,
613 B<no_version>, B<no_sigdump> and B<no_signame>.
619 Note: in these examples the '\' means the example should be all on one
622 Display the contents of a certificate:
624 openssl x509 -in cert.pem -noout -text
626 Display the certificate serial number:
628 openssl x509 -in cert.pem -noout -serial
630 Display the certificate subject name:
632 openssl x509 -in cert.pem -noout -subject
634 Display the certificate subject name in RFC2253 form:
636 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
638 Display the certificate subject name in oneline form on a terminal
641 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
643 Display the certificate MD5 fingerprint:
645 openssl x509 -in cert.pem -noout -fingerprint
647 Display the certificate SHA1 fingerprint:
649 openssl x509 -sha1 -in cert.pem -noout -fingerprint
651 Convert a certificate from PEM to DER format:
653 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
655 Convert a certificate to a certificate request:
657 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
659 Convert a certificate request into a self signed certificate using
662 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
663 -signkey key.pem -out cacert.pem
665 Sign a certificate request using the CA certificate above and add user
666 certificate extensions:
668 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
669 -CA cacert.pem -CAkey key.pem -CAcreateserial
672 Set a certificate to be trusted for SSL client use and change set its alias to
675 openssl x509 -in cert.pem -addtrust clientAuth \
676 -setalias "Steve's Class 1 CA" -out trust.pem
680 The PEM format uses the header and footer lines:
682 -----BEGIN CERTIFICATE-----
683 -----END CERTIFICATE-----
685 it will also handle files containing:
687 -----BEGIN X509 CERTIFICATE-----
688 -----END X509 CERTIFICATE-----
690 Trusted certificates have the lines
692 -----BEGIN TRUSTED CERTIFICATE-----
693 -----END TRUSTED CERTIFICATE-----
695 The conversion to UTF8 format used with the name options assumes that
696 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
697 and MSIE do this as do many certificates. So although this is incorrect
698 it is more likely to display the majority of certificates correctly.
700 The B<-fingerprint> option takes the digest of the DER encoded certificate.
701 This is commonly called a "fingerprint". Because of the nature of message
702 digests the fingerprint of a certificate is unique to that certificate and
703 two certificates with the same fingerprint can be considered to be the same.
705 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
707 The B<-email> option searches the subject name and the subject alternative
708 name extension. Only unique email addresses will be printed out: it will
709 not print the same address more than once.
711 =head1 CERTIFICATE EXTENSIONS
713 The B<-purpose> option checks the certificate extensions and determines
714 what the certificate can be used for. The actual checks done are rather
715 complex and include various hacks and workarounds to handle broken
716 certificates and software.
718 The same code is used when verifying untrusted certificates in chains
719 so this section is useful if a chain is rejected by the verify code.
721 The basicConstraints extension CA flag is used to determine whether the
722 certificate can be used as a CA. If the CA flag is true then it is a CA,
723 if the CA flag is false then it is not a CA. B<All> CAs should have the
726 If the basicConstraints extension is absent then the certificate is
727 considered to be a "possible CA" other extensions are checked according
728 to the intended use of the certificate. A warning is given in this case
729 because the certificate should really not be regarded as a CA: however
730 it is allowed to be a CA to work around some broken software.
732 If the certificate is a V1 certificate (and thus has no extensions) and
733 it is self signed it is also assumed to be a CA but a warning is again
734 given: this is to work around the problem of Verisign roots which are V1
735 self signed certificates.
737 If the keyUsage extension is present then additional restraints are
738 made on the uses of the certificate. A CA certificate B<must> have the
739 keyCertSign bit set if the keyUsage extension is present.
741 The extended key usage extension places additional restrictions on the
742 certificate uses. If this extension is present (whether critical or not)
743 the key can only be used for the purposes specified.
745 A complete description of each test is given below. The comments about
746 basicConstraints and keyUsage and V1 certificates above apply to B<all>
754 The extended key usage extension must be absent or include the "web client
755 authentication" OID. keyUsage must be absent or it must have the
756 digitalSignature bit set. Netscape certificate type must be absent or it must
757 have the SSL client bit set.
759 =item B<SSL Client CA>
761 The extended key usage extension must be absent or include the "web client
762 authentication" OID. Netscape certificate type must be absent or it must have
763 the SSL CA bit set: this is used as a work around if the basicConstraints
768 The extended key usage extension must be absent or include the "web server
769 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
770 must have the digitalSignature, the keyEncipherment set or both bits set.
771 Netscape certificate type must be absent or have the SSL server bit set.
773 =item B<SSL Server CA>
775 The extended key usage extension must be absent or include the "web server
776 authentication" and/or one of the SGC OIDs. Netscape certificate type must
777 be absent or the SSL CA bit must be set: this is used as a work around if the
778 basicConstraints extension is absent.
780 =item B<Netscape SSL Server>
782 For Netscape SSL clients to connect to an SSL server it must have the
783 keyEncipherment bit set if the keyUsage extension is present. This isn't
784 always valid because some cipher suites use the key for digital signing.
785 Otherwise it is the same as a normal SSL server.
787 =item B<Common S/MIME Client Tests>
789 The extended key usage extension must be absent or include the "email
790 protection" OID. Netscape certificate type must be absent or should have the
791 S/MIME bit set. If the S/MIME bit is not set in netscape certificate type
792 then the SSL client bit is tolerated as an alternative but a warning is shown:
793 this is because some Verisign certificates don't set the S/MIME bit.
795 =item B<S/MIME Signing>
797 In addition to the common S/MIME client tests the digitalSignature bit must
798 be set if the keyUsage extension is present.
800 =item B<S/MIME Encryption>
802 In addition to the common S/MIME tests the keyEncipherment bit must be set
803 if the keyUsage extension is present.
807 The extended key usage extension must be absent or include the "email
808 protection" OID. Netscape certificate type must be absent or must have the
809 S/MIME CA bit set: this is used as a work around if the basicConstraints
814 The keyUsage extension must be absent or it must have the CRL signing bit
817 =item B<CRL Signing CA>
819 The normal CA tests apply. Except in this case the basicConstraints extension
826 Extensions in certificates are not transferred to certificate requests and
829 It is possible to produce invalid certificates or requests by specifying the
830 wrong private key or using inconsistent options in some cases: these should
833 There should be options to explicitly set such things as start and end
834 dates rather than an offset from the current time.
836 The code to implement the verify behaviour described in the B<TRUST SETTINGS>
837 is currently being developed. It thus describes the intended behaviour rather
838 than the current behaviour. It is hoped that it will represent reality in
839 OpenSSL 0.9.5 and later.
843 L<req(1)|req(1)>, L<ca(1)|ca(1)>, L<genrsa(1)|genrsa(1)>,
844 L<gendsa(1)|gendsa(1)>, L<verify(1)|verify(1)>
848 Before OpenSSL 0.9.8, the default digest for RSA keys was MD5.