5 openssl-x509 - Certificate display and signing utility
15 [B<-CAkeyform DER|PEM>]
46 [B<-signkey filename>]
53 [B<-CAserial filename>]
55 [B<-force_pubkey filename>]
63 [B<-extfile filename>]
64 [B<-extensions section>]
73 The B<x509> command is a multi purpose certificate utility. It can be
74 used to display certificate information, convert certificates to
75 various forms, sign certificate requests like a "mini CA" or edit
76 certificate trust settings.
78 Since there are a large number of options they will split up into
83 =head2 Input, Output, and General Purpose Options
89 Print out a usage message.
91 =item B<-inform DER|PEM>
93 This specifies the input format normally the command will expect an X509
94 certificate but this can change if other options such as B<-req> are
95 present. The DER format is the DER encoding of the certificate and PEM
96 is the base64 encoding of the DER encoding with header and footer lines
97 added. The default format is PEM.
99 =item B<-outform DER|PEM>
101 This specifies the output format, the options have the same meaning and default
102 as the B<-inform> option.
104 =item B<-in filename>
106 This specifies the input filename to read a certificate from or standard input
107 if this option is not specified.
109 =item B<-out filename>
111 This specifies the output filename to write to or standard output by
117 This affects any signing or display option that uses a message
118 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options.
119 Any digest supported by the OpenSSL B<dgst> command can be used.
120 If not specified then SHA1 is used with B<-fingerprint> or
121 the default digest for the signing algorithm is used, typically SHA256.
123 =item B<-rand file...>
125 A file or files containing random data used to seed the random number
127 Multiple files can be specified separated by an OS-dependent character.
128 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
131 =item [B<-writerand file>]
133 Writes random data to the specified I<file> upon exit.
134 This can be used with a subsequent B<-rand> flag.
138 Specifying an engine (by its unique B<id> string) will cause B<x509>
139 to attempt to obtain a functional reference to the specified engine,
140 thus initialising it if needed. The engine will then be set as the default
141 for all available algorithms.
143 =item B<-preserve_dates>
145 When signing a certificate, preserve the "notBefore" and "notAfter" dates
146 instead of adjusting them to current time and duration.
147 Cannot be used with the B<-days> option.
151 =head2 Display Options
153 Note: the B<-alias> and B<-purpose> options are also display options
154 but are described in the B<TRUST SETTINGS> section.
160 Prints out the certificate in text form. Full details are output including the
161 public key, signature algorithms, issuer and subject names, serial number
162 any extensions present and any trust settings.
164 =item B<-ext extensions>
166 Prints out the certificate extensions in text form. Extensions are specified
167 with a comma separated string, e.g., "subjectAltName,subjectKeyIdentifier".
168 See the L<x509v3_config(5)> manual page for the extension names.
170 =item B<-certopt option>
172 Customise the output format used with B<-text>. The B<option> argument
173 can be a single option or multiple options separated by commas. The
174 B<-certopt> switch may be also be used more than once to set multiple
175 options. See the B<TEXT OPTIONS> section for more information.
179 This option prevents output of the encoded version of the certificate.
183 Outputs the certificate's SubjectPublicKeyInfo block in PEM format.
187 This option prints out the value of the modulus of the public key
188 contained in the certificate.
192 Outputs the certificate serial number.
194 =item B<-subject_hash>
196 Outputs the "hash" of the certificate subject name. This is used in OpenSSL to
197 form an index to allow certificates in a directory to be looked up by subject
200 =item B<-issuer_hash>
202 Outputs the "hash" of the certificate issuer name.
206 Outputs the OCSP hash values for the subject name and public key.
210 Synonym for "-subject_hash" for backward compatibility reasons.
212 =item B<-subject_hash_old>
214 Outputs the "hash" of the certificate subject name using the older algorithm
215 as used by OpenSSL before version 1.0.0.
217 =item B<-issuer_hash_old>
219 Outputs the "hash" of the certificate issuer name using the older algorithm
220 as used by OpenSSL before version 1.0.0.
224 Outputs the subject name.
228 Outputs the issuer name.
230 =item B<-nameopt option>
232 Option which determines how the subject or issuer names are displayed. The
233 B<option> argument can be a single option or multiple options separated by
234 commas. Alternatively the B<-nameopt> switch may be used more than once to
235 set multiple options. See the B<NAME OPTIONS> section for more information.
239 Outputs the email address(es) if any.
243 Outputs the OCSP responder address(es) if any.
247 Prints out the start date of the certificate, that is the notBefore date.
251 Prints out the expiry date of the certificate, that is the notAfter date.
255 Prints out the start and expiry dates of a certificate.
257 =item B<-checkend arg>
259 Checks if the certificate expires within the next B<arg> seconds and exits
260 non-zero if yes it will expire or zero if not.
262 =item B<-fingerprint>
264 Calculates and outputs the digest of the DER encoded version of the entire
265 certificate (see digest options).
266 This is commonly called a "fingerprint". Because of the nature of message
267 digests, the fingerprint of a certificate is unique to that certificate and
268 two certificates with the same fingerprint can be considered to be the same.
272 This outputs the certificate in the form of a C source file.
276 =head2 Trust Settings
278 A B<trusted certificate> is an ordinary certificate which has several
279 additional pieces of information attached to it such as the permitted
280 and prohibited uses of the certificate and an "alias".
282 Normally when a certificate is being verified at least one certificate
283 must be "trusted". By default a trusted certificate must be stored
284 locally and must be a root CA: any certificate chain ending in this CA
285 is then usable for any purpose.
287 Trust settings currently are only used with a root CA. They allow a finer
288 control over the purposes the root CA can be used for. For example a CA
289 may be trusted for SSL client but not SSL server use.
291 See the description of the B<verify> utility for more information on the
292 meaning of trust settings.
294 Future versions of OpenSSL will recognize trust settings on any
295 certificate: not just root CAs.
302 This causes B<x509> to output a B<trusted> certificate. An ordinary
303 or trusted certificate can be input but by default an ordinary
304 certificate is output and any trust settings are discarded. With the
305 B<-trustout> option a trusted certificate is output. A trusted
306 certificate is automatically output if any trust settings are modified.
308 =item B<-setalias arg>
310 Sets the alias of the certificate. This will allow the certificate
311 to be referred to using a nickname for example "Steve's Certificate".
315 Outputs the certificate alias, if any.
319 Clears all the permitted or trusted uses of the certificate.
323 Clears all the prohibited or rejected uses of the certificate.
325 =item B<-addtrust arg>
327 Adds a trusted certificate use.
328 Any object name can be used here but currently only B<clientAuth> (SSL client
329 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
330 B<anyExtendedKeyUsage> are used.
331 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
332 enables all purposes when trusted.
333 Other OpenSSL applications may define additional uses.
335 =item B<-addreject arg>
337 Adds a prohibited use. It accepts the same values as the B<-addtrust>
342 This option performs tests on the certificate extensions and outputs
343 the results. For a more complete description see the B<CERTIFICATE
348 =head2 Signing Options
350 The B<x509> utility can be used to sign certificates and requests: it
351 can thus behave like a "mini CA".
355 =item B<-signkey filename>
357 This option causes the input file to be self signed using the supplied
360 It sets the issuer name to the subject name (i.e., makes it self-issued)
361 and changes the public key to the supplied value (unless overridden by
362 B<-force_pubkey>). It sets the validity start date to the current time
363 and the end date to a value determined by the B<-days> option.
364 It retains any certificate extensions unless the B<-clrext> option is supplied;
365 this includes, for example, any existing key identifier extensions.
367 =item B<-sigopt nm:v>
369 Pass options to the signature algorithm during sign or verify operations.
370 Names and values of these options are algorithm-specific.
374 The key password source. For more information about the format of B<arg>
375 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
379 Delete any extensions from a certificate. This option is used when a
380 certificate is being created from another certificate (for example with
381 the B<-signkey> or the B<-CA> options). Normally all extensions are
384 =item B<-keyform PEM|DER>
386 Specifies the format (DER or PEM) of the private key file used in the
391 Specifies the number of days to make a certificate valid for. The default
392 is 30 days. Cannot be used with the B<-preserve_dates> option.
396 Converts a certificate into a certificate request. The B<-signkey> option
397 is used to pass the required private key.
401 By default a certificate is expected on input. With this option a
402 certificate request is expected instead.
404 =item B<-set_serial n>
406 Specifies the serial number to use. This option can be used with either
407 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
408 option the serial number file (as specified by the B<-CAserial> or
409 B<-CAcreateserial> options) is not used.
411 The serial number can be decimal or hex (if preceded by B<0x>).
413 =item B<-CA filename>
415 Specifies the CA certificate to be used for signing. When this option is
416 present B<x509> behaves like a "mini CA". The input file is signed by this
417 CA using this option: that is its issuer name is set to the subject name
418 of the CA and it is digitally signed using the CAs private key.
420 This option is normally combined with the B<-req> option. Without the
421 B<-req> option the input is a certificate which must be self signed.
423 =item B<-CAkey filename>
425 Sets the CA private key to sign a certificate with. If this option is
426 not specified then it is assumed that the CA private key is present in
427 the CA certificate file.
429 =item B<-CAserial filename>
431 Sets the CA serial number file to use.
433 When the B<-CA> option is used to sign a certificate it uses a serial
434 number specified in a file. This file consists of one line containing
435 an even number of hex digits with the serial number to use. After each
436 use the serial number is incremented and written out to the file again.
438 The default filename consists of the CA certificate file base name with
439 ".srl" appended. For example if the CA certificate file is called
440 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
442 =item B<-CAcreateserial>
444 With this option the CA serial number file is created if it does not exist:
445 it will contain the serial number "02" and the certificate being signed will
446 have the 1 as its serial number. If the B<-CA> option is specified
447 and the serial number file does not exist a random number is generated;
448 this is the recommended practice.
450 =item B<-extfile filename>
452 File containing certificate extensions to use. If not specified then
453 no extensions are added to the certificate.
455 =item B<-extensions section>
457 The section to add certificate extensions from. If this option is not
458 specified then the extensions should either be contained in the unnamed
459 (default) section or the default section should contain a variable called
460 "extensions" which contains the section to use. See the
461 L<x509v3_config(5)> manual page for details of the
462 extension section format.
466 Generate a certificate from scratch, not using an input certificate
467 or certificate request. So the B<-in> option must not be used in this case.
468 Instead, the B<-subj> and <-force_pubkey> options need to be given.
470 =item B<-force_pubkey filename>
472 When a certificate is created set its public key to the key in B<filename>
473 instead of the key contained in the input or given with the B<-signkey> option.
475 This option is useful for creating self-issued certificates that are not
476 self-signed, for instance when the key cannot be used for signing, such as DH.
477 It can also be used in conjunction with b<-new> and B<-subj> to directly
478 generate a certificate containing any desired public key.
480 The format of the key file can be specified using the B<-keyform> option.
484 When a certificate is created set its subject name to the given value.
485 The arg must be formatted as I</type0=value0/type1=value1/type2=...>.
486 Keyword characters may be escaped by \ (backslash), and whitespace is retained.
487 Empty values are permitted, but the corresponding type will not be included
488 in the certificate. Giving a single I</> will lead to an empty sequence of RDNs
491 Unless the B<-CA> option is given the issuer is set to the same value.
493 This option can be used in conjunction with the B<-force_pubkey> option
494 to create a certificate even without providing an input certificate
495 or certificate request.
501 The B<nameopt> command line switch determines how the subject and issuer
502 names are displayed. If no B<nameopt> switch is present the default "oneline"
503 format is used which is compatible with previous versions of OpenSSL.
504 Each option is described in detail below, all options can be preceded by
505 a B<-> to turn the option off. Only the first four will normally be used.
515 Displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
516 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
517 B<sep_comma_plus>, B<dn_rev> and B<sname>.
521 A oneline format which is more readable than RFC2253. It is equivalent to
522 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
523 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
524 options. This is the I<default> of no name options are given explicitly.
528 A multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
529 B<space_eq>, B<lname> and B<align>.
533 Escape the "special" characters required by RFC2253 in a field. That is
534 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
535 and a space character at the beginning or end of a string.
539 Escape the "special" characters required by RFC2254 in a field. That is
540 the B<NUL> character as well as and B<()*>.
544 Escape control characters. That is those with ASCII values less than
545 0x20 (space) and the delete (0x7f) character. They are escaped using the
546 RFC2253 \XX notation (where XX are two hex digits representing the
551 Escape characters with the MSB set, that is with ASCII values larger than
556 Escapes some characters by surrounding the whole string with B<"> characters,
557 without the option all escaping is done with the B<\> character.
561 Convert all strings to UTF8 format first. This is required by RFC2253. If
562 you are lucky enough to have a UTF8 compatible terminal then the use
563 of this option (and B<not> setting B<esc_msb>) may result in the correct
564 display of multibyte (international) characters. Is this option is not
565 present then multibyte characters larger than 0xff will be represented
566 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
567 Also if this option is off any UTF8Strings will be converted to their
568 character form first.
572 This option does not attempt to interpret multibyte characters in any
573 way. That is their content octets are merely dumped as though one octet
574 represents each character. This is useful for diagnostic purposes but
575 will result in rather odd looking output.
579 Show the type of the ASN1 character string. The type precedes the
580 field contents. For example "BMPSTRING: Hello World".
584 When this option is set any fields that need to be hexdumped will
585 be dumped using the DER encoding of the field. Otherwise just the
586 content octets will be displayed. Both options use the RFC2253
591 Dump non character string types (for example OCTET STRING) if this
592 option is not set then non character string types will be displayed
593 as though each content octet represents a single character.
597 Dump all fields. This option when used with B<dump_der> allows the
598 DER encoding of the structure to be unambiguously determined.
600 =item B<dump_unknown>
602 Dump any field whose OID is not recognised by OpenSSL.
604 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
607 These options determine the field separators. The first character is
608 between Relative Distinguished Names (RDNs) and the second is between
609 multiple Attribute Value Assertions (AVAs, multiple AVAs are
610 very rare and their use is discouraged). The options ending in
611 "space" additionally place a space after the separator to make it
612 more readable. The B<sep_multiline> uses a linefeed character for
613 the RDN separator and a spaced B<+> for the AVA separator. It also
614 indents the fields by four characters. If no field separator is specified
615 then B<sep_comma_plus_space> is used by default.
619 Reverse the fields of the DN. This is required by RFC2253. As a side
620 effect this also reverses the order of multiple AVAs but this is
623 =item B<nofname>, B<sname>, B<lname>, B<oid>
625 These options alter how the field name is displayed. B<nofname> does
626 not display the field at all. B<sname> uses the "short name" form
627 (CN for commonName for example). B<lname> uses the long form.
628 B<oid> represents the OID in numerical form and is useful for
633 Align field values for a more readable output. Only usable with
638 Places spaces round the B<=> character which follows the field
645 As well as customising the name output format, it is also possible to
646 customise the actual fields printed using the B<certopt> options when
647 the B<text> option is present. The default behaviour is to print all fields.
653 Use the old format. This is equivalent to specifying no output options at all.
657 Don't print header information: that is the lines saying "Certificate"
662 Don't print out the version number.
666 Don't print out the serial number.
670 Don't print out the signature algorithm used.
674 Don't print the validity, that is the B<notBefore> and B<notAfter> fields.
678 Don't print out the subject name.
682 Don't print out the issuer name.
686 Don't print out the public key.
690 Don't give a hexadecimal dump of the certificate signature.
694 Don't print out certificate trust information.
696 =item B<no_extensions>
698 Don't print out any X509V3 extensions.
702 Retain default extension behaviour: attempt to print out unsupported
703 certificate extensions.
707 Print an error message for unsupported certificate extensions.
711 ASN1 parse unsupported extensions.
715 Hex dump unsupported extensions.
719 The value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
720 B<no_header>, and B<no_version>.
726 Note: in these examples the '\' means the example should be all on one
729 Display the contents of a certificate:
731 openssl x509 -in cert.pem -noout -text
733 Display the "Subject Alternative Name" extension of a certificate:
735 openssl x509 -in cert.pem -noout -ext subjectAltName
737 Display more extensions of a certificate:
739 openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType
741 Display the certificate serial number:
743 openssl x509 -in cert.pem -noout -serial
745 Display the certificate subject name:
747 openssl x509 -in cert.pem -noout -subject
749 Display the certificate subject name in RFC2253 form:
751 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
753 Display the certificate subject name in oneline form on a terminal
756 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
758 Display the certificate SHA1 fingerprint:
760 openssl x509 -sha1 -in cert.pem -noout -fingerprint
762 Convert a certificate from PEM to DER format:
764 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
766 Convert a certificate to a certificate request:
768 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
770 Convert a certificate request into a self signed certificate using
773 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
774 -signkey key.pem -out cacert.pem
776 Sign a certificate request using the CA certificate above and add user
777 certificate extensions:
779 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
780 -CA cacert.pem -CAkey key.pem -CAcreateserial
783 Set a certificate to be trusted for SSL client use and change set its alias to
786 openssl x509 -in cert.pem -addtrust clientAuth \
787 -setalias "Steve's Class 1 CA" -out trust.pem
791 The PEM format uses the header and footer lines:
793 -----BEGIN CERTIFICATE-----
794 -----END CERTIFICATE-----
796 it will also handle files containing:
798 -----BEGIN X509 CERTIFICATE-----
799 -----END X509 CERTIFICATE-----
801 Trusted certificates have the lines
803 -----BEGIN TRUSTED CERTIFICATE-----
804 -----END TRUSTED CERTIFICATE-----
806 The conversion to UTF8 format used with the name options assumes that
807 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
808 and MSIE do this as do many certificates. So although this is incorrect
809 it is more likely to display the majority of certificates correctly.
811 The B<-email> option searches the subject name and the subject alternative
812 name extension. Only unique email addresses will be printed out: it will
813 not print the same address more than once.
815 =head1 CERTIFICATE EXTENSIONS
817 The B<-purpose> option checks the certificate extensions and determines
818 what the certificate can be used for. The actual checks done are rather
819 complex and include various hacks and workarounds to handle broken
820 certificates and software.
822 The same code is used when verifying untrusted certificates in chains
823 so this section is useful if a chain is rejected by the verify code.
825 The basicConstraints extension CA flag is used to determine whether the
826 certificate can be used as a CA. If the CA flag is true then it is a CA,
827 if the CA flag is false then it is not a CA. B<All> CAs should have the
830 If the basicConstraints extension is absent then the certificate is
831 considered to be a "possible CA" other extensions are checked according
832 to the intended use of the certificate. A warning is given in this case
833 because the certificate should really not be regarded as a CA: however
834 it is allowed to be a CA to work around some broken software.
836 If the certificate is a V1 certificate (and thus has no extensions) and
837 it is self signed it is also assumed to be a CA but a warning is again
838 given: this is to work around the problem of Verisign roots which are V1
839 self signed certificates.
841 If the keyUsage extension is present then additional restraints are
842 made on the uses of the certificate. A CA certificate B<must> have the
843 keyCertSign bit set if the keyUsage extension is present.
845 The extended key usage extension places additional restrictions on the
846 certificate uses. If this extension is present (whether critical or not)
847 the key can only be used for the purposes specified.
849 A complete description of each test is given below. The comments about
850 basicConstraints and keyUsage and V1 certificates above apply to B<all>
858 The extended key usage extension must be absent or include the "web client
859 authentication" OID. keyUsage must be absent or it must have the
860 digitalSignature bit set. Netscape certificate type must be absent or it must
861 have the SSL client bit set.
863 =item B<SSL Client CA>
865 The extended key usage extension must be absent or include the "web client
866 authentication" OID. Netscape certificate type must be absent or it must have
867 the SSL CA bit set: this is used as a work around if the basicConstraints
872 The extended key usage extension must be absent or include the "web server
873 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
874 must have the digitalSignature, the keyEncipherment set or both bits set.
875 Netscape certificate type must be absent or have the SSL server bit set.
877 =item B<SSL Server CA>
879 The extended key usage extension must be absent or include the "web server
880 authentication" and/or one of the SGC OIDs. Netscape certificate type must
881 be absent or the SSL CA bit must be set: this is used as a work around if the
882 basicConstraints extension is absent.
884 =item B<Netscape SSL Server>
886 For Netscape SSL clients to connect to an SSL server it must have the
887 keyEncipherment bit set if the keyUsage extension is present. This isn't
888 always valid because some cipher suites use the key for digital signing.
889 Otherwise it is the same as a normal SSL server.
891 =item B<Common S/MIME Client Tests>
893 The extended key usage extension must be absent or include the "email
894 protection" OID. Netscape certificate type must be absent or should have the
895 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
896 then the SSL client bit is tolerated as an alternative but a warning is shown:
897 this is because some Verisign certificates don't set the S/MIME bit.
899 =item B<S/MIME Signing>
901 In addition to the common S/MIME client tests the digitalSignature bit or
902 the nonRepudiation bit must be set if the keyUsage extension is present.
904 =item B<S/MIME Encryption>
906 In addition to the common S/MIME tests the keyEncipherment bit must be set
907 if the keyUsage extension is present.
911 The extended key usage extension must be absent or include the "email
912 protection" OID. Netscape certificate type must be absent or must have the
913 S/MIME CA bit set: this is used as a work around if the basicConstraints
918 The keyUsage extension must be absent or it must have the CRL signing bit
921 =item B<CRL Signing CA>
923 The normal CA tests apply. Except in this case the basicConstraints extension
930 Extensions in certificates are not transferred to certificate requests and
933 It is possible to produce invalid certificates or requests by specifying the
934 wrong private key or using inconsistent options in some cases: these should
937 There should be options to explicitly set such things as start and end
938 dates rather than an offset from the current time.
945 L<openssl-genrsa(1)>,
946 L<openssl-gendsa(1)>,
947 L<openssl-verify(1)>,
952 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
953 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
954 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
955 canonical version of the DN using SHA1. This means that any directories using
956 the old form must have their links rebuilt using B<c_rehash> or similar.
960 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
962 Licensed under the Apache License 2.0 (the "License"). You may not use
963 this file except in compliance with the License. You can obtain a copy
964 in the file LICENSE in the source distribution or at
965 L<https://www.openssl.org/source/license.html>.