6 x509 - Certificate display and signing utility
11 [B<-inform DER|PEM|NET>]
12 [B<-outform DER|PEM|NET>]
15 [B<-CAkeyform DER|PEM>]
39 [B<-signkey filename>]
45 [B<-CAserial filename>]
48 [B<-md2|-md5|-sha1|-mdc2>]
50 [B<-extfile filename>]
51 [B<-extensions section>]
55 The B<x509> command is a multi purpose certificate utility. It can be
56 used to display certificate information, convert certificates to
57 various forms, sign certificate requests like a "mini CA" or edit
58 certificate trust settings.
60 Since there are a large number of options they will split up into
64 =head1 INPUT, OUTPUT AND GENERAL PURPOSE OPTIONS
68 =item B<-inform DER|PEM|NET>
70 This specifies the input format normally the command will expect an X509
71 certificate but this can change if other options such as B<-req> are
72 present. The DER format is the DER encoding of the certificate and PEM
73 is the base64 encoding of the DER encoding with header and footer lines
74 added. The NET option is an obscure Netscape server format that is now
77 =item B<-outform DER|PEM|NET>
79 This specifies the output format, the options have the same meaning as the
84 This specifies the input filename to read a certificate from or standard input
85 if this option is not specified.
87 =item B<-out filename>
89 This specifies the output filename to write to or standard output by
92 =item B<-md2|-md5|-sha1|-mdc2>
94 the digest to use. This affects any signing or display option that uses a message
95 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options. If not
96 specified then MD5 is used. If the key being used to sign with is a DSA key then
97 this option has no effect: SHA1 is always used with DSA keys.
102 =head1 DISPLAY OPTIONS
104 Note: the B<-alias> and B<-purpose> options are also display options
105 but are described in the B<TRUST OPTIONS> section.
111 prints out the certificate in text form. Full details are output including the
112 public key, signature algorithms, issuer and subject names, serial number
113 any extensions present and any trust settings.
117 this option prevents output of the encoded version of the request.
121 this option prints out the value of the modulus of the public key
122 contained in the certificate.
126 outputs the certificate serial number.
130 outputs the "hash" of the certificate subject name. This is used in OpenSSL to
131 form an index to allow certificates in a directory to be looked up by subject
136 outputs the subject name.
140 outputs the issuer name.
142 =item B<-nameopt option>
144 option which determine how the subject or issuer names are displayed. This
145 option may be used more than once to set multiple options. See the B<NAME
146 OPTIONS> section for more information.
150 outputs the email address(es) if any.
154 prints out the start date of the certificate, that is the notBefore date.
158 prints out the expiry date of the certificate, that is the notAfter date.
162 prints out the start and expiry dates of a certificate.
164 =item B<-fingerprint>
166 prints out the digest of the DER encoded version of the whole certificate.
170 this outputs the certificate in the form of a C source file.
174 =head1 TRUST SETTINGS
176 Please note these options are currently experimental and may well change.
178 A B<trusted certificate> is an ordinary certificate which has several
179 additional pieces of information attached to it such as the permitted
180 and prohibited uses of the certificate and an "alias".
182 Normally when a certificate is being verified at least one certificate
183 must be "trusted". By default a trusted certificate must be stored
184 locally and must be a root CA: any certificate chain ending in this CA
185 is then usable for any purpose.
187 Trust settings currently are only used with a root CA. They allow a finer
188 control over the purposes the root CA can be used for. For example a CA
189 may be trusted for SSL client but not SSL server use.
191 See the description of the B<verify> utility for more information on the
192 meaning of trust settings.
194 Future versions of OpenSSL will recognize trust settings on any
195 certificate: not just root CAs.
202 this causes B<x509> to output a B<trusted> certificate. An ordinary
203 or trusted certificate can be input but by default an ordinary
204 certificate is output and any trust settings are discarded. With the
205 B<-trustout> option a trusted certificate is output. A trusted
206 certificate is automatically output if any trust settings are modified.
208 =item B<-setalias arg>
210 sets the alias of the certificate. This will allow the certificate
211 to be referred to using a nickname for example "Steve's Certificate".
215 outputs the certificate alias, if any.
219 clears all the permitted or trusted uses of the certificate.
223 clears all the prohibited or rejected uses of the certificate.
225 =item B<-addtrust arg>
227 adds a trusted certificate use. Any object name can be used here
228 but currently only B<clientAuth> (SSL client use), B<serverAuth>
229 (SSL server use) and B<emailProtection> (S/MIME email) are used.
230 Other OpenSSL applications may define additional uses.
232 =item B<-addreject arg>
234 adds a prohibited use. It accepts the same values as the B<-addtrust>
239 this option performs tests on the certificate extensions and outputs
240 the results. For a more complete description see the B<CERTIFICATE
245 =head1 SIGNING OPTIONS
247 The B<x509> utility can be used to sign certificates and requests: it
248 can thus behave like a "mini CA".
252 =item B<-signkey filename>
254 this option causes the input file to be self signed using the supplied
257 If the input file is a certificate it sets the issuer name to the
258 subject name (i.e. makes it self signed) changes the public key to the
259 supplied value and changes the start and end dates. The start date is
260 set to the current time and the end date is set to a value determined
261 by the B<-days> option. Any certificate extensions are retained unless
262 the B<-clrext> option is supplied.
264 If the input is a certificate request then a self signed certificate
265 is created using the supplied private key using the subject name in
270 delete any extensions from a certificate. This option is used when a
271 certificate is being created from another certificate (for example with
272 the B<-signkey> or the B<-CA> options). Normally all extensions are
275 =item B<-keyform PEM|DER>
277 specifies the format (DER or PEM) of the private key file used in the
282 specifies the number of days to make a certificate valid for. The default
287 converts a certificate into a certificate request. The B<-signkey> option
288 is used to pass the required private key.
292 by default a certificate is expected on input. With this option a
293 certificate request is expected instead.
295 =item B<-CA filename>
297 specifies the CA certificate to be used for signing. When this option is
298 present B<x509> behaves like a "mini CA". The input file is signed by this
299 CA using this option: that is its issuer name is set to the subject name
300 of the CA and it is digitally signed using the CAs private key.
302 This option is normally combined with the B<-req> option. Without the
303 B<-req> option the input is a certificate which must be self signed.
305 =item B<-CAkey filename>
307 sets the CA private key to sign a certificate with. If this option is
308 not specified then it is assumed that the CA private key is present in
309 the CA certificate file.
311 =item B<-CAserial filename>
313 sets the CA serial number file to use.
315 When the B<-CA> option is used to sign a certificate it uses a serial
316 number specified in a file. This file consist of one line containing
317 an even number of hex digits with the serial number to use. After each
318 use the serial number is incremented and written out to the file again.
320 The default filename consists of the CA certificate file base name with
321 ".srl" appended. For example if the CA certificate file is called
322 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
324 =item B<-CAcreateserial filename>
326 with this option the CA serial number file is created if it does not exist:
327 it will contain the serial number "02" and the certificate being signed will
328 have the 1 as its serial number. Normally if the B<-CA> option is specified
329 and the serial number file does not exist it is an error.
331 =item B<-extfile filename>
333 file containing certificate extensions to use. If not specified then
334 no extensions are added to the certificate.
336 =item B<-extensions section>
338 the section to add certificate extensions from. If this option is not
339 specified then the extensions should either be contained in the unnamed
340 (default) section or the default section should contain a variable called
341 "extensions" which contains the section to use.
347 The B<nameopt> command line switch determines how the subject and issuer
348 names are displayed. If no B<nameopt> switch is present the default "oneline"
349 format is used which is compatible with previous versions of OpenSSL.
350 Each option is described in detail below, all options can be preceded by
351 a B<-> to turn the option off. Only the first four will normally be used.
357 use the old format. This is equivalent to specifying no name options at all.
361 displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
362 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
363 B<sep_comma_plus>, B<dn_rev> and B<sname>.
367 a oneline format which is more readable than RFC2253. It is equivalent to
368 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
369 B<dump_der>, B<use_quote>, B<sep_comma_plus_spc>, B<spc_eq> and B<sname>
374 a multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
375 B<spc_eq> and B<lname>.
379 escape the "special" characters required by RFC2253 in a field That is
380 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginnging of a string
381 and a space character at the beginning or end of a string.
385 escape control characters. That is those with ASCII values less than
386 0x20 (space) and the delete (0x7f) character. They are escaped using the
387 RFC2253 \XX notation (where XX are two hex digits representing the
392 escape characters with the MSB set, that is with ASCII values larger than
397 escapes some characters by surrounding the whole string with B<"> characters,
398 without the option all escaping is done with the B<\> character.
402 convert all strings to UTF8 format first. This is required by RFC2253. If
403 you are lucky enough to have a UTF8 compatible terminal then the use
404 of this option (and B<not> setting B<esc_msb>) may result in the correct
405 display of multibyte (international) characters. Is this option is not
406 present then multibyte characters larger than 0xff will be represented
407 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
408 Also if this option is off any UTF8Strings will be converted to their
409 character form first.
413 this option does not attempt to interpret multibyte characters in any
414 way. That is their content octets are merely dumped as though one octet
415 represents each character. This is useful for diagnostic purposes but
416 will result in rather odd looking output.
420 show the type of the ASN1 character string. The type precedes the
421 field contents. For example "BMPSTRING: Hello World".
425 when this option is set any fields that need to be hexdumped will
426 be dumped using the DER encoding of the field. Otherwise just the
427 content octets will be displayed. Both options use the RFC2253
432 dump non character string types (for example OCTET STRING) if this
433 option is not set then non character string types will be displayed
434 as though each content octet repesents a single character.
438 dump all fields. This option when used with B<dump_der> allows the
439 DER encoding of the structure to be unambiguously determined.
441 =item B<dump_unknown>
443 dump any field whose OID is not recognised by OpenSSL.
445 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
448 these options determine the field separators. The first character is
449 between RDNs and the second between multiple AVAs (multiple AVAs are
450 very rare and their use is discouraged). The options ending in
451 "space" additionally place a space after the separator to make it
452 more readable. The B<sep_multiline> uses a linefeed character for
453 the RDN separator and a spaced B<+> for the AVA separator. It also
454 indents the fields by four characters.
458 reverse the fields of the DN. This is required by RFC2253. As a side
459 effect this also reverses the order of multiple AVAs but this is
462 =item B<nofname>, B<sname>, B<lname>, B<oid>
464 these options alter how the field name is displayed. B<nofname> does
465 not display the field at all. B<sname> uses the "short name" form
466 (CN for commonName for example). B<lname> uses the long form.
467 B<oid> represents the OID in numerical form and is useful for
472 places spaces round the B<=> character which follows the field
479 Note: in these examples the '\' means the example should be all on one
482 Display the contents of a certificate:
484 openssl x509 -in cert.pem -noout -text
486 Display the certificate serial number:
488 openssl x509 -in cert.pem -noout -serial
490 Display the certificate subject name:
492 openssl x509 -in cert.pem -noout -subject
494 Display the certificate subject name in RFC2253 form:
496 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
498 Display the certificate subject name in oneline form on a terminal
501 openssl x509 -in cert.pem -noout -subject -nameopt oneline -nameopt -escmsb
503 Display the certificate MD5 fingerprint:
505 openssl x509 -in cert.pem -noout -fingerprint
507 Display the certificate SHA1 fingerprint:
509 openssl x509 -sha1 -in cert.pem -noout -fingerprint
511 Convert a certificate from PEM to DER format:
513 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
515 Convert a certificate to a certificate request:
517 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
519 Convert a certificate request into a self signed certificate using
522 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
523 -signkey key.pem -out cacert.pem
525 Sign a certificate request using the CA certificate above and add user
526 certificate extensions:
528 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
529 -CA cacert.pem -CAkey key.pem -CAcreateserial
532 Set a certificate to be trusted for SSL client use and change set its alias to
535 openssl x509 -in cert.pem -addtrust sslclient \
536 -alias "Steve's Class 1 CA" -out trust.pem
540 The PEM format uses the header and footer lines:
542 -----BEGIN CERTIFICATE----
543 -----END CERTIFICATE----
545 it will also handle files containing:
547 -----BEGIN X509 CERTIFICATE----
548 -----END X509 CERTIFICATE----
550 Trusted certificates have the lines
552 -----BEGIN TRUSTED CERTIFICATE----
553 -----END TRUSTED CERTIFICATE----
555 The conversion to UTF8 format used with the name options assumes that
556 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
557 and MSIE do this as do many certificates. So although this is incorrect
558 it is more likely to display the majority of certificates correctly.
560 The B<-fingerprint> option takes the digest of the DER encoded certificate.
561 This is commonly called a "fingerprint". Because of the nature of message
562 digests the fingerprint of a certificate is unique to that certificate and
563 two certificates with the same fingerprint can be considered to be the same.
565 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
567 The B<-email> option searches the subject name and the subject alternative
568 name extension. Only unique email addresses will be printed out: it will
569 not print the same address more than once.
571 =head1 CERTIFICATE EXTENSIONS
573 The B<-purpose> option checks the certificate extensions and determines
574 what the certificate can be used for. The actual checks done are rather
575 complex and include various hacks and workarounds to handle broken
576 certificates and software.
578 The same code is used when verifying untrusted certificates in chains
579 so this section is useful if a chain is rejected by the verify code.
581 The basicConstraints extension CA flag is used to determine whether the
582 certificate can be used as a CA. If the CA flag is true then it is a CA,
583 if the CA flag is false then it is not a CA. B<All> CAs should have the
586 If the basicConstraints extension is absent then the certificate is
587 considered to be a "possible CA" other extensions are checked according
588 to the intended use of the certificate. A warning is given in this case
589 because the certificate should really not be regarded as a CA: however
590 it is allowed to be a CA to work around some broken software.
592 If the certificate is a V1 certificate (and thus has no extensions) and
593 it is self signed it is also assumed to be a CA but a warning is again
594 given: this is to work around the problem of Verisign roots which are V1
595 self signed certificates.
597 If the keyUsage extension is present then additional restraints are
598 made on the uses of the certificate. A CA certificate B<must> have the
599 keyCertSign bit set if the keyUsage extension is present.
601 The extended key usage extension places additional restrictions on the
602 certificate uses. If this extension is present (whether critical or not)
603 the key can only be used for the purposes specified.
605 A complete description of each test is given below. The comments about
606 basicConstraints and keyUsage and V1 certificates above apply to B<all>
614 The extended key usage extension must be absent or include the "web client
615 authentication" OID. keyUsage must be absent or it must have the
616 digitalSignature bit set. Netscape certificate type must be absent or it must
617 have the SSL client bit set.
619 =item B<SSL Client CA>
621 The extended key usage extension must be absent or include the "web client
622 authentication" OID. Netscape certificate type must be absent or it must have
623 the SSL CA bit set: this is used as a work around if the basicConstraints
628 The extended key usage extension must be absent or include the "web server
629 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
630 must have the digitalSignature, the keyEncipherment set or both bits set.
631 Netscape certificate type must be absent or have the SSL server bit set.
633 =item B<SSL Server CA>
635 The extended key usage extension must be absent or include the "web server
636 authentication" and/or one of the SGC OIDs. Netscape certificate type must
637 be absent or the SSL CA bit must be set: this is used as a work around if the
638 basicConstraints extension is absent.
640 =item B<Netscape SSL Server>
642 For Netscape SSL clients to connect to an SSL server it must have the
643 keyEncipherment bit set if the keyUsage extension is present. This isn't
644 always valid because some cipher suites use the key for digital signing.
645 Otherwise it is the same as a normal SSL server.
647 =item B<Common S/MIME Client Tests>
649 The extended key usage extension must be absent or include the "email
650 protection" OID. Netscape certificate type must be absent or should have the
651 S/MIME bit set. If the S/MIME bit is not set in netscape certificate type
652 then the SSL client bit is tolerated as an alternative but a warning is shown:
653 this is because some Verisign certificates don't set the S/MIME bit.
655 =item B<S/MIME Signing>
657 In addition to the common S/MIME client tests the digitalSignature bit must
658 be set if the keyUsage extension is present.
660 =item B<S/MIME Encryption>
662 In addition to the common S/MIME tests the keyEncipherment bit must be set
663 if the keyUsage extension is present.
667 The extended key usage extension must be absent or include the "email
668 protection" OID. Netscape certificate type must be absent or must have the
669 S/MIME CA bit set: this is used as a work around if the basicConstraints
674 The keyUsage extension must be absent or it must have the CRL signing bit
677 =item B<CRL Signing CA>
679 The normal CA tests apply. Except in this case the basicConstraints extension
686 Extensions in certificates are not transferred to certificate requests and
689 It is possible to produce invalid certificates or requests by specifying the
690 wrong private key or using inconsistent options in some cases: these should
693 There should be options to explicitly set such things as start and end
694 dates rather than an offset from the current time.
696 The code to implement the verify behaviour described in the B<TRUST SETTINGS>
697 is currently being developed. It thus describes the intended behaviour rather
698 than the current behaviour. It is hoped that it will represent reality in
699 OpenSSL 0.9.5 and later.
703 L<req(1)|req(1)>, L<ca(1)|ca(1)>, L<genrsa(1)|genrsa(1)>,
704 L<gendsa(1)|gendsa(1)>, L<verify(1)|verify(1)>