6 x509 - Certificate display and signing utility
11 [B<-inform DER|PEM|NET>]
12 [B<-outform DER|PEM|NET>]
15 [B<-CAkeyform DER|PEM>]
40 [B<-signkey filename>]
46 [B<-CAserial filename>]
49 [B<-md2|-md5|-sha1|-mdc2>]
51 [B<-extfile filename>]
52 [B<-extensions section>]
56 The B<x509> command is a multi purpose certificate utility. It can be
57 used to display certificate information, convert certificates to
58 various forms, sign certificate requests like a "mini CA" or edit
59 certificate trust settings.
61 Since there are a large number of options they will split up into
66 =head2 INPUT, OUTPUT AND GENERAL PURPOSE OPTIONS
70 =item B<-inform DER|PEM|NET>
72 This specifies the input format normally the command will expect an X509
73 certificate but this can change if other options such as B<-req> are
74 present. The DER format is the DER encoding of the certificate and PEM
75 is the base64 encoding of the DER encoding with header and footer lines
76 added. The NET option is an obscure Netscape server format that is now
79 =item B<-outform DER|PEM|NET>
81 This specifies the output format, the options have the same meaning as the
86 This specifies the input filename to read a certificate from or standard input
87 if this option is not specified.
89 =item B<-out filename>
91 This specifies the output filename to write to or standard output by
94 =item B<-md2|-md5|-sha1|-mdc2>
96 the digest to use. This affects any signing or display option that uses a message
97 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options. If not
98 specified then MD5 is used. If the key being used to sign with is a DSA key then
99 this option has no effect: SHA1 is always used with DSA keys.
104 =head2 DISPLAY OPTIONS
106 Note: the B<-alias> and B<-purpose> options are also display options
107 but are described in the B<TRUST SETTINGS> section.
113 prints out the certificate in text form. Full details are output including the
114 public key, signature algorithms, issuer and subject names, serial number
115 any extensions present and any trust settings.
117 =item B<-certopt option>
119 customise the output format used with B<-text>. The B<option> argument can be
120 a single option or multiple options separated by commas. The B<-certopt> switch
121 may be also be used more than once to set multiple options. See the B<TEXT OPTIONS>
122 section for more information.
126 this option prevents output of the encoded version of the request.
130 this option prints out the value of the modulus of the public key
131 contained in the certificate.
135 outputs the certificate serial number.
139 outputs the "hash" of the certificate subject name. This is used in OpenSSL to
140 form an index to allow certificates in a directory to be looked up by subject
145 outputs the subject name.
149 outputs the issuer name.
151 =item B<-nameopt option>
153 option which determines how the subject or issuer names are displayed. The
154 B<option> argument can be a single option or multiple options separated by
155 commas. Alternatively the B<-nameopt> switch may be used more than once to
156 set multiple options. See the B<NAME OPTIONS> section for more information.
160 outputs the email address(es) if any.
164 prints out the start date of the certificate, that is the notBefore date.
168 prints out the expiry date of the certificate, that is the notAfter date.
172 prints out the start and expiry dates of a certificate.
174 =item B<-fingerprint>
176 prints out the digest of the DER encoded version of the whole certificate
177 (see digest options).
181 this outputs the certificate in the form of a C source file.
185 =head2 TRUST SETTINGS
187 Please note these options are currently experimental and may well change.
189 A B<trusted certificate> is an ordinary certificate which has several
190 additional pieces of information attached to it such as the permitted
191 and prohibited uses of the certificate and an "alias".
193 Normally when a certificate is being verified at least one certificate
194 must be "trusted". By default a trusted certificate must be stored
195 locally and must be a root CA: any certificate chain ending in this CA
196 is then usable for any purpose.
198 Trust settings currently are only used with a root CA. They allow a finer
199 control over the purposes the root CA can be used for. For example a CA
200 may be trusted for SSL client but not SSL server use.
202 See the description of the B<verify> utility for more information on the
203 meaning of trust settings.
205 Future versions of OpenSSL will recognize trust settings on any
206 certificate: not just root CAs.
213 this causes B<x509> to output a B<trusted> certificate. An ordinary
214 or trusted certificate can be input but by default an ordinary
215 certificate is output and any trust settings are discarded. With the
216 B<-trustout> option a trusted certificate is output. A trusted
217 certificate is automatically output if any trust settings are modified.
219 =item B<-setalias arg>
221 sets the alias of the certificate. This will allow the certificate
222 to be referred to using a nickname for example "Steve's Certificate".
226 outputs the certificate alias, if any.
230 clears all the permitted or trusted uses of the certificate.
234 clears all the prohibited or rejected uses of the certificate.
236 =item B<-addtrust arg>
238 adds a trusted certificate use. Any object name can be used here
239 but currently only B<clientAuth> (SSL client use), B<serverAuth>
240 (SSL server use) and B<emailProtection> (S/MIME email) are used.
241 Other OpenSSL applications may define additional uses.
243 =item B<-addreject arg>
245 adds a prohibited use. It accepts the same values as the B<-addtrust>
250 this option performs tests on the certificate extensions and outputs
251 the results. For a more complete description see the B<CERTIFICATE
256 =head2 SIGNING OPTIONS
258 The B<x509> utility can be used to sign certificates and requests: it
259 can thus behave like a "mini CA".
263 =item B<-signkey filename>
265 this option causes the input file to be self signed using the supplied
268 If the input file is a certificate it sets the issuer name to the
269 subject name (i.e. makes it self signed) changes the public key to the
270 supplied value and changes the start and end dates. The start date is
271 set to the current time and the end date is set to a value determined
272 by the B<-days> option. Any certificate extensions are retained unless
273 the B<-clrext> option is supplied.
275 If the input is a certificate request then a self signed certificate
276 is created using the supplied private key using the subject name in
281 delete any extensions from a certificate. This option is used when a
282 certificate is being created from another certificate (for example with
283 the B<-signkey> or the B<-CA> options). Normally all extensions are
286 =item B<-keyform PEM|DER>
288 specifies the format (DER or PEM) of the private key file used in the
293 specifies the number of days to make a certificate valid for. The default
298 converts a certificate into a certificate request. The B<-signkey> option
299 is used to pass the required private key.
303 by default a certificate is expected on input. With this option a
304 certificate request is expected instead.
306 =item B<-set_serial n>
308 specifies the serial number to use. This option can be used with either
309 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
310 option the serial number file (as specified by the B<-CAserial> or
311 B<-CAcreateserial> options) is not used.
313 The serial number can be decimal or hex (if preceded by B<0x>). Negative
314 serial numbers can also be specified but their use is not recommended.
316 =item B<-CA filename>
318 specifies the CA certificate to be used for signing. When this option is
319 present B<x509> behaves like a "mini CA". The input file is signed by this
320 CA using this option: that is its issuer name is set to the subject name
321 of the CA and it is digitally signed using the CAs private key.
323 This option is normally combined with the B<-req> option. Without the
324 B<-req> option the input is a certificate which must be self signed.
326 =item B<-CAkey filename>
328 sets the CA private key to sign a certificate with. If this option is
329 not specified then it is assumed that the CA private key is present in
330 the CA certificate file.
332 =item B<-CAserial filename>
334 sets the CA serial number file to use.
336 When the B<-CA> option is used to sign a certificate it uses a serial
337 number specified in a file. This file consist of one line containing
338 an even number of hex digits with the serial number to use. After each
339 use the serial number is incremented and written out to the file again.
341 The default filename consists of the CA certificate file base name with
342 ".srl" appended. For example if the CA certificate file is called
343 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
345 =item B<-CAcreateserial>
347 with this option the CA serial number file is created if it does not exist:
348 it will contain the serial number "02" and the certificate being signed will
349 have the 1 as its serial number. Normally if the B<-CA> option is specified
350 and the serial number file does not exist it is an error.
352 =item B<-extfile filename>
354 file containing certificate extensions to use. If not specified then
355 no extensions are added to the certificate.
357 =item B<-extensions section>
359 the section to add certificate extensions from. If this option is not
360 specified then the extensions should either be contained in the unnamed
361 (default) section or the default section should contain a variable called
362 "extensions" which contains the section to use.
368 The B<nameopt> command line switch determines how the subject and issuer
369 names are displayed. If no B<nameopt> switch is present the default "oneline"
370 format is used which is compatible with previous versions of OpenSSL.
371 Each option is described in detail below, all options can be preceded by
372 a B<-> to turn the option off. Only the first four will normally be used.
378 use the old format. This is equivalent to specifying no name options at all.
382 displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
383 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
384 B<sep_comma_plus>, B<dn_rev> and B<sname>.
388 a oneline format which is more readable than RFC2253. It is equivalent to
389 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
390 B<dump_der>, B<use_quote>, B<sep_comma_plus_spc>, B<spc_eq> and B<sname>
395 a multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
396 B<spc_eq>, B<lname> and B<align>.
400 escape the "special" characters required by RFC2253 in a field That is
401 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
402 and a space character at the beginning or end of a string.
406 escape control characters. That is those with ASCII values less than
407 0x20 (space) and the delete (0x7f) character. They are escaped using the
408 RFC2253 \XX notation (where XX are two hex digits representing the
413 escape characters with the MSB set, that is with ASCII values larger than
418 escapes some characters by surrounding the whole string with B<"> characters,
419 without the option all escaping is done with the B<\> character.
423 convert all strings to UTF8 format first. This is required by RFC2253. If
424 you are lucky enough to have a UTF8 compatible terminal then the use
425 of this option (and B<not> setting B<esc_msb>) may result in the correct
426 display of multibyte (international) characters. Is this option is not
427 present then multibyte characters larger than 0xff will be represented
428 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
429 Also if this option is off any UTF8Strings will be converted to their
430 character form first.
434 this option does not attempt to interpret multibyte characters in any
435 way. That is their content octets are merely dumped as though one octet
436 represents each character. This is useful for diagnostic purposes but
437 will result in rather odd looking output.
441 show the type of the ASN1 character string. The type precedes the
442 field contents. For example "BMPSTRING: Hello World".
446 when this option is set any fields that need to be hexdumped will
447 be dumped using the DER encoding of the field. Otherwise just the
448 content octets will be displayed. Both options use the RFC2253
453 dump non character string types (for example OCTET STRING) if this
454 option is not set then non character string types will be displayed
455 as though each content octet represents a single character.
459 dump all fields. This option when used with B<dump_der> allows the
460 DER encoding of the structure to be unambiguously determined.
462 =item B<dump_unknown>
464 dump any field whose OID is not recognised by OpenSSL.
466 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
469 these options determine the field separators. The first character is
470 between RDNs and the second between multiple AVAs (multiple AVAs are
471 very rare and their use is discouraged). The options ending in
472 "space" additionally place a space after the separator to make it
473 more readable. The B<sep_multiline> uses a linefeed character for
474 the RDN separator and a spaced B<+> for the AVA separator. It also
475 indents the fields by four characters.
479 reverse the fields of the DN. This is required by RFC2253. As a side
480 effect this also reverses the order of multiple AVAs but this is
483 =item B<nofname>, B<sname>, B<lname>, B<oid>
485 these options alter how the field name is displayed. B<nofname> does
486 not display the field at all. B<sname> uses the "short name" form
487 (CN for commonName for example). B<lname> uses the long form.
488 B<oid> represents the OID in numerical form and is useful for
493 align field values for a more readable output. Only usable with
498 places spaces round the B<=> character which follows the field
505 As well as customising the name output format, it is also possible to
506 customise the actual fields printed using the B<certopt> options when
507 the B<text> option is present. The default behaviour is to print all fields.
513 use the old format. This is equivalent to specifying no output options at all.
517 don't print header information: that is the lines saying "Certificate" and "Data".
521 don't print out the version number.
525 don't print out the serial number.
529 don't print out the signature algorithm used.
533 don't print the validity, that is the B<notBefore> and B<notAfter> fields.
537 don't print out the subject name.
541 don't print out the issuer name.
545 don't print out the public key.
549 don't give a hexadecimal dump of the certificate signature.
553 don't print out certificate trust information.
555 =item B<no_extensions>
557 don't print out any X509V3 extensions.
561 retain default extension behaviour: attempt to print out unsupported certificate extensions.
565 print an error message for unsupported certificate extensions.
569 ASN1 parse unsupported extensions.
573 hex dump unsupported extensions.
577 the value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>, B<no_header>,
578 B<no_version>, B<no_sigdump> and B<no_signame>.
584 Note: in these examples the '\' means the example should be all on one
587 Display the contents of a certificate:
589 openssl x509 -in cert.pem -noout -text
591 Display the certificate serial number:
593 openssl x509 -in cert.pem -noout -serial
595 Display the certificate subject name:
597 openssl x509 -in cert.pem -noout -subject
599 Display the certificate subject name in RFC2253 form:
601 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
603 Display the certificate subject name in oneline form on a terminal
606 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-escmsb
608 Display the certificate MD5 fingerprint:
610 openssl x509 -in cert.pem -noout -fingerprint
612 Display the certificate SHA1 fingerprint:
614 openssl x509 -sha1 -in cert.pem -noout -fingerprint
616 Convert a certificate from PEM to DER format:
618 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
620 Convert a certificate to a certificate request:
622 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
624 Convert a certificate request into a self signed certificate using
627 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
628 -signkey key.pem -out cacert.pem
630 Sign a certificate request using the CA certificate above and add user
631 certificate extensions:
633 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
634 -CA cacert.pem -CAkey key.pem -CAcreateserial
637 Set a certificate to be trusted for SSL client use and change set its alias to
640 openssl x509 -in cert.pem -addtrust sslclient \
641 -alias "Steve's Class 1 CA" -out trust.pem
645 The PEM format uses the header and footer lines:
647 -----BEGIN CERTIFICATE-----
648 -----END CERTIFICATE-----
650 it will also handle files containing:
652 -----BEGIN X509 CERTIFICATE-----
653 -----END X509 CERTIFICATE-----
655 Trusted certificates have the lines
657 -----BEGIN TRUSTED CERTIFICATE-----
658 -----END TRUSTED CERTIFICATE-----
660 The conversion to UTF8 format used with the name options assumes that
661 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
662 and MSIE do this as do many certificates. So although this is incorrect
663 it is more likely to display the majority of certificates correctly.
665 The B<-fingerprint> option takes the digest of the DER encoded certificate.
666 This is commonly called a "fingerprint". Because of the nature of message
667 digests the fingerprint of a certificate is unique to that certificate and
668 two certificates with the same fingerprint can be considered to be the same.
670 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
672 The B<-email> option searches the subject name and the subject alternative
673 name extension. Only unique email addresses will be printed out: it will
674 not print the same address more than once.
676 =head1 CERTIFICATE EXTENSIONS
678 The B<-purpose> option checks the certificate extensions and determines
679 what the certificate can be used for. The actual checks done are rather
680 complex and include various hacks and workarounds to handle broken
681 certificates and software.
683 The same code is used when verifying untrusted certificates in chains
684 so this section is useful if a chain is rejected by the verify code.
686 The basicConstraints extension CA flag is used to determine whether the
687 certificate can be used as a CA. If the CA flag is true then it is a CA,
688 if the CA flag is false then it is not a CA. B<All> CAs should have the
691 If the basicConstraints extension is absent then the certificate is
692 considered to be a "possible CA" other extensions are checked according
693 to the intended use of the certificate. A warning is given in this case
694 because the certificate should really not be regarded as a CA: however
695 it is allowed to be a CA to work around some broken software.
697 If the certificate is a V1 certificate (and thus has no extensions) and
698 it is self signed it is also assumed to be a CA but a warning is again
699 given: this is to work around the problem of Verisign roots which are V1
700 self signed certificates.
702 If the keyUsage extension is present then additional restraints are
703 made on the uses of the certificate. A CA certificate B<must> have the
704 keyCertSign bit set if the keyUsage extension is present.
706 The extended key usage extension places additional restrictions on the
707 certificate uses. If this extension is present (whether critical or not)
708 the key can only be used for the purposes specified.
710 A complete description of each test is given below. The comments about
711 basicConstraints and keyUsage and V1 certificates above apply to B<all>
719 The extended key usage extension must be absent or include the "web client
720 authentication" OID. keyUsage must be absent or it must have the
721 digitalSignature bit set. Netscape certificate type must be absent or it must
722 have the SSL client bit set.
724 =item B<SSL Client CA>
726 The extended key usage extension must be absent or include the "web client
727 authentication" OID. Netscape certificate type must be absent or it must have
728 the SSL CA bit set: this is used as a work around if the basicConstraints
733 The extended key usage extension must be absent or include the "web server
734 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
735 must have the digitalSignature, the keyEncipherment set or both bits set.
736 Netscape certificate type must be absent or have the SSL server bit set.
738 =item B<SSL Server CA>
740 The extended key usage extension must be absent or include the "web server
741 authentication" and/or one of the SGC OIDs. Netscape certificate type must
742 be absent or the SSL CA bit must be set: this is used as a work around if the
743 basicConstraints extension is absent.
745 =item B<Netscape SSL Server>
747 For Netscape SSL clients to connect to an SSL server it must have the
748 keyEncipherment bit set if the keyUsage extension is present. This isn't
749 always valid because some cipher suites use the key for digital signing.
750 Otherwise it is the same as a normal SSL server.
752 =item B<Common S/MIME Client Tests>
754 The extended key usage extension must be absent or include the "email
755 protection" OID. Netscape certificate type must be absent or should have the
756 S/MIME bit set. If the S/MIME bit is not set in netscape certificate type
757 then the SSL client bit is tolerated as an alternative but a warning is shown:
758 this is because some Verisign certificates don't set the S/MIME bit.
760 =item B<S/MIME Signing>
762 In addition to the common S/MIME client tests the digitalSignature bit must
763 be set if the keyUsage extension is present.
765 =item B<S/MIME Encryption>
767 In addition to the common S/MIME tests the keyEncipherment bit must be set
768 if the keyUsage extension is present.
772 The extended key usage extension must be absent or include the "email
773 protection" OID. Netscape certificate type must be absent or must have the
774 S/MIME CA bit set: this is used as a work around if the basicConstraints
779 The keyUsage extension must be absent or it must have the CRL signing bit
782 =item B<CRL Signing CA>
784 The normal CA tests apply. Except in this case the basicConstraints extension
791 Extensions in certificates are not transferred to certificate requests and
794 It is possible to produce invalid certificates or requests by specifying the
795 wrong private key or using inconsistent options in some cases: these should
798 There should be options to explicitly set such things as start and end
799 dates rather than an offset from the current time.
801 The code to implement the verify behaviour described in the B<TRUST SETTINGS>
802 is currently being developed. It thus describes the intended behaviour rather
803 than the current behaviour. It is hoped that it will represent reality in
804 OpenSSL 0.9.5 and later.
808 L<req(1)|req(1)>, L<ca(1)|ca(1)>, L<genrsa(1)|genrsa(1)>,
809 L<gendsa(1)|gendsa(1)>, L<verify(1)|verify(1)>