6 x509 - Certificate display and signing utility
14 [B<-keyform DER|PEM|ENGINE>]
16 [B<-CAkeyform DER|PEM>]
47 [B<-signkey filename>]
54 [B<-CAserial filename>]
55 [B<-force_pubkey key>]
62 [B<-extfile filename>]
63 [B<-extensions section>]
72 The B<x509> command is a multi purpose certificate utility. It can be
73 used to display certificate information, convert certificates to
74 various forms, sign certificate requests like a "mini CA" or edit
75 certificate trust settings.
77 Since there are a large number of options they will split up into
82 =head2 Input, Output, and General Purpose Options
88 Print out a usage message.
90 =item B<-inform DER|PEM>
92 This specifies the input format normally the command will expect an X509
93 certificate but this can change if other options such as B<-req> are
94 present. The DER format is the DER encoding of the certificate and PEM
95 is the base64 encoding of the DER encoding with header and footer lines
96 added. The default format is PEM.
98 =item B<-outform DER|PEM>
100 This specifies the output format, the options have the same meaning and default
101 as the B<-inform> option.
103 =item B<-in filename>
105 This specifies the input filename to read a certificate from or standard input
106 if this option is not specified.
108 =item B<-out filename>
110 This specifies the output filename to write to or standard output by
116 This affects any signing or display option that uses a message
117 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options.
118 Any digest supported by the OpenSSL B<dgst> command can be used.
119 If not specified then SHA1 is used with B<-fingerprint> or
120 the default digest for the signing algorithm is used, typically SHA256.
122 =item B<-rand file...>
124 A file or files containing random data used to seed the random number
126 Multiple files can be specified separated by an OS-dependent character.
127 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
130 =item [B<-writerand file>]
132 Writes random data to the specified I<file> upon exit.
133 This can be used with a subsequent B<-rand> flag.
137 Specifying an engine (by its unique B<id> string) will cause B<x509>
138 to attempt to obtain a functional reference to the specified engine,
139 thus initialising it if needed. The engine will then be set as the default
140 for all available algorithms.
142 =item B<-preserve_dates>
144 When signing a certificate, preserve the "notBefore" and "notAfter" dates instead
145 of adjusting them to current time and duration. Cannot be used with the B<-days> option.
149 =head2 Display Options
151 Note: the B<-alias> and B<-purpose> options are also display options
152 but are described in the B<TRUST SETTINGS> section.
158 Prints out the certificate in text form. Full details are output including the
159 public key, signature algorithms, issuer and subject names, serial number
160 any extensions present and any trust settings.
162 =item B<-ext extensions>
164 Prints out the certificate extensions in text form. Extensions are specified
165 with a comma separated string, e.g., "subjectAltName,subjectKeyIdentifier".
166 See the L<x509v3_config(5)> manual page for the extension names.
168 =item B<-certopt option>
170 Customise the output format used with B<-text>. The B<option> argument
171 can be a single option or multiple options separated by commas. The
172 B<-certopt> switch may be also be used more than once to set multiple
173 options. See the B<TEXT OPTIONS> section for more information.
177 This option prevents output of the encoded version of the certificate.
181 Outputs the certificate's SubjectPublicKeyInfo block in PEM format.
185 This option prints out the value of the modulus of the public key
186 contained in the certificate.
190 Outputs the certificate serial number.
192 =item B<-subject_hash>
194 Outputs the "hash" of the certificate subject name. This is used in OpenSSL to
195 form an index to allow certificates in a directory to be looked up by subject
198 =item B<-issuer_hash>
200 Outputs the "hash" of the certificate issuer name.
204 Outputs the OCSP hash values for the subject name and public key.
208 Synonym for "-subject_hash" for backward compatibility reasons.
210 =item B<-subject_hash_old>
212 Outputs the "hash" of the certificate subject name using the older algorithm
213 as used by OpenSSL before version 1.0.0.
215 =item B<-issuer_hash_old>
217 Outputs the "hash" of the certificate issuer name using the older algorithm
218 as used by OpenSSL before version 1.0.0.
222 Outputs the subject name.
226 Outputs the issuer name.
228 =item B<-nameopt option>
230 Option which determines how the subject or issuer names are displayed. The
231 B<option> argument can be a single option or multiple options separated by
232 commas. Alternatively the B<-nameopt> switch may be used more than once to
233 set multiple options. See the B<NAME OPTIONS> section for more information.
237 Outputs the email address(es) if any.
241 Outputs the OCSP responder address(es) if any.
245 Prints out the start date of the certificate, that is the notBefore date.
249 Prints out the expiry date of the certificate, that is the notAfter date.
253 Prints out the start and expiry dates of a certificate.
255 =item B<-checkend arg>
257 Checks if the certificate expires within the next B<arg> seconds and exits
258 non-zero if yes it will expire or zero if not.
260 =item B<-fingerprint>
262 Calculates and outputs the digest of the DER encoded version of the entire
263 certificate (see digest options).
264 This is commonly called a "fingerprint". Because of the nature of message
265 digests, the fingerprint of a certificate is unique to that certificate and
266 two certificates with the same fingerprint can be considered to be the same.
270 This outputs the certificate in the form of a C source file.
274 =head2 Trust Settings
276 A B<trusted certificate> is an ordinary certificate which has several
277 additional pieces of information attached to it such as the permitted
278 and prohibited uses of the certificate and an "alias".
280 Normally when a certificate is being verified at least one certificate
281 must be "trusted". By default a trusted certificate must be stored
282 locally and must be a root CA: any certificate chain ending in this CA
283 is then usable for any purpose.
285 Trust settings currently are only used with a root CA. They allow a finer
286 control over the purposes the root CA can be used for. For example a CA
287 may be trusted for SSL client but not SSL server use.
289 See the description of the B<verify> utility for more information on the
290 meaning of trust settings.
292 Future versions of OpenSSL will recognize trust settings on any
293 certificate: not just root CAs.
300 This causes B<x509> to output a B<trusted> certificate. An ordinary
301 or trusted certificate can be input but by default an ordinary
302 certificate is output and any trust settings are discarded. With the
303 B<-trustout> option a trusted certificate is output. A trusted
304 certificate is automatically output if any trust settings are modified.
306 =item B<-setalias arg>
308 Sets the alias of the certificate. This will allow the certificate
309 to be referred to using a nickname for example "Steve's Certificate".
313 Outputs the certificate alias, if any.
317 Clears all the permitted or trusted uses of the certificate.
321 Clears all the prohibited or rejected uses of the certificate.
323 =item B<-addtrust arg>
325 Adds a trusted certificate use.
326 Any object name can be used here but currently only B<clientAuth> (SSL client
327 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
328 B<anyExtendedKeyUsage> are used.
329 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
330 enables all purposes when trusted.
331 Other OpenSSL applications may define additional uses.
333 =item B<-addreject arg>
335 Adds a prohibited use. It accepts the same values as the B<-addtrust>
340 This option performs tests on the certificate extensions and outputs
341 the results. For a more complete description see the B<CERTIFICATE
346 =head2 Signing Options
348 The B<x509> utility can be used to sign certificates and requests: it
349 can thus behave like a "mini CA".
353 =item B<-signkey filename>
355 This option causes the input file to be self signed using the supplied
358 If the input file is a certificate it sets the issuer name to the
359 subject name (i.e. makes it self signed) changes the public key to the
360 supplied value and changes the start and end dates. The start date is
361 set to the current time and the end date is set to a value determined
362 by the B<-days> option. Any certificate extensions are retained unless
363 the B<-clrext> option is supplied; this includes, for example, any existing
364 key identifier extensions.
366 If the input is a certificate request then a self signed certificate
367 is created using the supplied private key using the subject name in
370 =item B<-sigopt nm:v>
372 Pass options to the signature algorithm during sign or verify operations.
373 Names and values of these options are algorithm-specific.
377 The key password source. For more information about the format of B<arg>
378 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
382 Delete any extensions from a certificate. This option is used when a
383 certificate is being created from another certificate (for example with
384 the B<-signkey> or the B<-CA> options). Normally all extensions are
387 =item B<-keyform PEM|DER|ENGINE>
389 Specifies the format (DER or PEM) of the private key file used in the
394 Specifies the number of days to make a certificate valid for. The default
395 is 30 days. Cannot be used with the B<-preserve_dates> option.
399 Converts a certificate into a certificate request. The B<-signkey> option
400 is used to pass the required private key.
404 By default a certificate is expected on input. With this option a
405 certificate request is expected instead.
407 =item B<-set_serial n>
409 Specifies the serial number to use. This option can be used with either
410 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
411 option the serial number file (as specified by the B<-CAserial> or
412 B<-CAcreateserial> options) is not used.
414 The serial number can be decimal or hex (if preceded by B<0x>).
416 =item B<-CA filename>
418 Specifies the CA certificate to be used for signing. When this option is
419 present B<x509> behaves like a "mini CA". The input file is signed by this
420 CA using this option: that is its issuer name is set to the subject name
421 of the CA and it is digitally signed using the CAs private key.
423 This option is normally combined with the B<-req> option. Without the
424 B<-req> option the input is a certificate which must be self signed.
426 =item B<-CAkey filename>
428 Sets the CA private key to sign a certificate with. If this option is
429 not specified then it is assumed that the CA private key is present in
430 the CA certificate file.
432 =item B<-CAserial filename>
434 Sets the CA serial number file to use.
436 When the B<-CA> option is used to sign a certificate it uses a serial
437 number specified in a file. This file consists of one line containing
438 an even number of hex digits with the serial number to use. After each
439 use the serial number is incremented and written out to the file again.
441 The default filename consists of the CA certificate file base name with
442 ".srl" appended. For example if the CA certificate file is called
443 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
445 =item B<-CAcreateserial>
447 With this option the CA serial number file is created if it does not exist:
448 it will contain the serial number "02" and the certificate being signed will
449 have the 1 as its serial number. If the B<-CA> option is specified
450 and the serial number file does not exist a random number is generated;
451 this is the recommended practice.
453 =item B<-extfile filename>
455 File containing certificate extensions to use. If not specified then
456 no extensions are added to the certificate.
458 =item B<-extensions section>
460 The section to add certificate extensions from. If this option is not
461 specified then the extensions should either be contained in the unnamed
462 (default) section or the default section should contain a variable called
463 "extensions" which contains the section to use. See the
464 L<x509v3_config(5)> manual page for details of the
465 extension section format.
467 =item B<-force_pubkey key>
469 When a certificate is created set its public key to B<key> instead of the
470 key in the certificate or certificate request. This option is useful for
471 creating certificates where the algorithm can't normally sign requests, for
474 The format or B<key> can be specified using the B<-keyform> option.
480 The B<nameopt> command line switch determines how the subject and issuer
481 names are displayed. If no B<nameopt> switch is present the default "oneline"
482 format is used which is compatible with previous versions of OpenSSL.
483 Each option is described in detail below, all options can be preceded by
484 a B<-> to turn the option off. Only the first four will normally be used.
494 Displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
495 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
496 B<sep_comma_plus>, B<dn_rev> and B<sname>.
500 A oneline format which is more readable than RFC2253. It is equivalent to
501 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
502 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
503 options. This is the I<default> of no name options are given explicitly.
507 A multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
508 B<space_eq>, B<lname> and B<align>.
512 Escape the "special" characters required by RFC2253 in a field. That is
513 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
514 and a space character at the beginning or end of a string.
518 Escape the "special" characters required by RFC2254 in a field. That is
519 the B<NUL> character as well as and B<()*>.
523 Escape control characters. That is those with ASCII values less than
524 0x20 (space) and the delete (0x7f) character. They are escaped using the
525 RFC2253 \XX notation (where XX are two hex digits representing the
530 Escape characters with the MSB set, that is with ASCII values larger than
535 Escapes some characters by surrounding the whole string with B<"> characters,
536 without the option all escaping is done with the B<\> character.
540 Convert all strings to UTF8 format first. This is required by RFC2253. If
541 you are lucky enough to have a UTF8 compatible terminal then the use
542 of this option (and B<not> setting B<esc_msb>) may result in the correct
543 display of multibyte (international) characters. Is this option is not
544 present then multibyte characters larger than 0xff will be represented
545 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
546 Also if this option is off any UTF8Strings will be converted to their
547 character form first.
551 This option does not attempt to interpret multibyte characters in any
552 way. That is their content octets are merely dumped as though one octet
553 represents each character. This is useful for diagnostic purposes but
554 will result in rather odd looking output.
558 Show the type of the ASN1 character string. The type precedes the
559 field contents. For example "BMPSTRING: Hello World".
563 When this option is set any fields that need to be hexdumped will
564 be dumped using the DER encoding of the field. Otherwise just the
565 content octets will be displayed. Both options use the RFC2253
570 Dump non character string types (for example OCTET STRING) if this
571 option is not set then non character string types will be displayed
572 as though each content octet represents a single character.
576 Dump all fields. This option when used with B<dump_der> allows the
577 DER encoding of the structure to be unambiguously determined.
579 =item B<dump_unknown>
581 Dump any field whose OID is not recognised by OpenSSL.
583 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
586 These options determine the field separators. The first character is
587 between RDNs and the second between multiple AVAs (multiple AVAs are
588 very rare and their use is discouraged). The options ending in
589 "space" additionally place a space after the separator to make it
590 more readable. The B<sep_multiline> uses a linefeed character for
591 the RDN separator and a spaced B<+> for the AVA separator. It also
592 indents the fields by four characters. If no field separator is specified
593 then B<sep_comma_plus_space> is used by default.
597 Reverse the fields of the DN. This is required by RFC2253. As a side
598 effect this also reverses the order of multiple AVAs but this is
601 =item B<nofname>, B<sname>, B<lname>, B<oid>
603 These options alter how the field name is displayed. B<nofname> does
604 not display the field at all. B<sname> uses the "short name" form
605 (CN for commonName for example). B<lname> uses the long form.
606 B<oid> represents the OID in numerical form and is useful for
611 Align field values for a more readable output. Only usable with
616 Places spaces round the B<=> character which follows the field
623 As well as customising the name output format, it is also possible to
624 customise the actual fields printed using the B<certopt> options when
625 the B<text> option is present. The default behaviour is to print all fields.
631 Use the old format. This is equivalent to specifying no output options at all.
635 Don't print header information: that is the lines saying "Certificate"
640 Don't print out the version number.
644 Don't print out the serial number.
648 Don't print out the signature algorithm used.
652 Don't print the validity, that is the B<notBefore> and B<notAfter> fields.
656 Don't print out the subject name.
660 Don't print out the issuer name.
664 Don't print out the public key.
668 Don't give a hexadecimal dump of the certificate signature.
672 Don't print out certificate trust information.
674 =item B<no_extensions>
676 Don't print out any X509V3 extensions.
680 Retain default extension behaviour: attempt to print out unsupported
681 certificate extensions.
685 Print an error message for unsupported certificate extensions.
689 ASN1 parse unsupported extensions.
693 Hex dump unsupported extensions.
697 The value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
698 B<no_header>, and B<no_version>.
704 Note: in these examples the '\' means the example should be all on one
707 Display the contents of a certificate:
709 openssl x509 -in cert.pem -noout -text
711 Display the "Subject Alternative Name" extension of a certificate:
713 openssl x509 -in cert.pem -noout -ext subjectAltName
715 Display more extensions of a certificate:
717 openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType
719 Display the certificate serial number:
721 openssl x509 -in cert.pem -noout -serial
723 Display the certificate subject name:
725 openssl x509 -in cert.pem -noout -subject
727 Display the certificate subject name in RFC2253 form:
729 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
731 Display the certificate subject name in oneline form on a terminal
734 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
736 Display the certificate SHA1 fingerprint:
738 openssl x509 -sha1 -in cert.pem -noout -fingerprint
740 Convert a certificate from PEM to DER format:
742 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
744 Convert a certificate to a certificate request:
746 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
748 Convert a certificate request into a self signed certificate using
751 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
752 -signkey key.pem -out cacert.pem
754 Sign a certificate request using the CA certificate above and add user
755 certificate extensions:
757 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
758 -CA cacert.pem -CAkey key.pem -CAcreateserial
761 Set a certificate to be trusted for SSL client use and change set its alias to
764 openssl x509 -in cert.pem -addtrust clientAuth \
765 -setalias "Steve's Class 1 CA" -out trust.pem
769 The PEM format uses the header and footer lines:
771 -----BEGIN CERTIFICATE-----
772 -----END CERTIFICATE-----
774 it will also handle files containing:
776 -----BEGIN X509 CERTIFICATE-----
777 -----END X509 CERTIFICATE-----
779 Trusted certificates have the lines
781 -----BEGIN TRUSTED CERTIFICATE-----
782 -----END TRUSTED CERTIFICATE-----
784 The conversion to UTF8 format used with the name options assumes that
785 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
786 and MSIE do this as do many certificates. So although this is incorrect
787 it is more likely to display the majority of certificates correctly.
789 The B<-email> option searches the subject name and the subject alternative
790 name extension. Only unique email addresses will be printed out: it will
791 not print the same address more than once.
793 =head1 CERTIFICATE EXTENSIONS
795 The B<-purpose> option checks the certificate extensions and determines
796 what the certificate can be used for. The actual checks done are rather
797 complex and include various hacks and workarounds to handle broken
798 certificates and software.
800 The same code is used when verifying untrusted certificates in chains
801 so this section is useful if a chain is rejected by the verify code.
803 The basicConstraints extension CA flag is used to determine whether the
804 certificate can be used as a CA. If the CA flag is true then it is a CA,
805 if the CA flag is false then it is not a CA. B<All> CAs should have the
808 If the basicConstraints extension is absent then the certificate is
809 considered to be a "possible CA" other extensions are checked according
810 to the intended use of the certificate. A warning is given in this case
811 because the certificate should really not be regarded as a CA: however
812 it is allowed to be a CA to work around some broken software.
814 If the certificate is a V1 certificate (and thus has no extensions) and
815 it is self signed it is also assumed to be a CA but a warning is again
816 given: this is to work around the problem of Verisign roots which are V1
817 self signed certificates.
819 If the keyUsage extension is present then additional restraints are
820 made on the uses of the certificate. A CA certificate B<must> have the
821 keyCertSign bit set if the keyUsage extension is present.
823 The extended key usage extension places additional restrictions on the
824 certificate uses. If this extension is present (whether critical or not)
825 the key can only be used for the purposes specified.
827 A complete description of each test is given below. The comments about
828 basicConstraints and keyUsage and V1 certificates above apply to B<all>
836 The extended key usage extension must be absent or include the "web client
837 authentication" OID. keyUsage must be absent or it must have the
838 digitalSignature bit set. Netscape certificate type must be absent or it must
839 have the SSL client bit set.
841 =item B<SSL Client CA>
843 The extended key usage extension must be absent or include the "web client
844 authentication" OID. Netscape certificate type must be absent or it must have
845 the SSL CA bit set: this is used as a work around if the basicConstraints
850 The extended key usage extension must be absent or include the "web server
851 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
852 must have the digitalSignature, the keyEncipherment set or both bits set.
853 Netscape certificate type must be absent or have the SSL server bit set.
855 =item B<SSL Server CA>
857 The extended key usage extension must be absent or include the "web server
858 authentication" and/or one of the SGC OIDs. Netscape certificate type must
859 be absent or the SSL CA bit must be set: this is used as a work around if the
860 basicConstraints extension is absent.
862 =item B<Netscape SSL Server>
864 For Netscape SSL clients to connect to an SSL server it must have the
865 keyEncipherment bit set if the keyUsage extension is present. This isn't
866 always valid because some cipher suites use the key for digital signing.
867 Otherwise it is the same as a normal SSL server.
869 =item B<Common S/MIME Client Tests>
871 The extended key usage extension must be absent or include the "email
872 protection" OID. Netscape certificate type must be absent or should have the
873 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
874 then the SSL client bit is tolerated as an alternative but a warning is shown:
875 this is because some Verisign certificates don't set the S/MIME bit.
877 =item B<S/MIME Signing>
879 In addition to the common S/MIME client tests the digitalSignature bit or
880 the nonRepudiation bit must be set if the keyUsage extension is present.
882 =item B<S/MIME Encryption>
884 In addition to the common S/MIME tests the keyEncipherment bit must be set
885 if the keyUsage extension is present.
889 The extended key usage extension must be absent or include the "email
890 protection" OID. Netscape certificate type must be absent or must have the
891 S/MIME CA bit set: this is used as a work around if the basicConstraints
896 The keyUsage extension must be absent or it must have the CRL signing bit
899 =item B<CRL Signing CA>
901 The normal CA tests apply. Except in this case the basicConstraints extension
908 Extensions in certificates are not transferred to certificate requests and
911 It is possible to produce invalid certificates or requests by specifying the
912 wrong private key or using inconsistent options in some cases: these should
915 There should be options to explicitly set such things as start and end
916 dates rather than an offset from the current time.
920 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
921 L<gendsa(1)>, L<verify(1)>,
926 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
927 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
928 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
929 canonical version of the DN using SHA1. This means that any directories using
930 the old form must have their links rebuilt using B<c_rehash> or similar.
934 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
936 Licensed under the OpenSSL license (the "License"). You may not use
937 this file except in compliance with the License. You can obtain a copy
938 in the file LICENSE in the source distribution or at
939 L<https://www.openssl.org/source/license.html>.