6 x509 - Certificate display and signing utility
16 [B<-CAkeyform DER|PEM>]
47 [B<-signkey filename>]
54 [B<-CAserial filename>]
56 [B<-force_pubkey filename>]
64 [B<-extfile filename>]
65 [B<-extensions section>]
74 The B<x509> command is a multi purpose certificate utility. It can be
75 used to display certificate information, convert certificates to
76 various forms, sign certificate requests like a "mini CA" or edit
77 certificate trust settings.
79 Since there are a large number of options they will split up into
84 =head2 Input, Output, and General Purpose Options
90 Print out a usage message.
92 =item B<-inform DER|PEM>
94 This specifies the input format normally the command will expect an X509
95 certificate but this can change if other options such as B<-req> are
96 present. The DER format is the DER encoding of the certificate and PEM
97 is the base64 encoding of the DER encoding with header and footer lines
98 added. The default format is PEM.
100 =item B<-outform DER|PEM>
102 This specifies the output format, the options have the same meaning and default
103 as the B<-inform> option.
105 =item B<-in filename>
107 This specifies the input filename to read a certificate from or standard input
108 if this option is not specified.
110 =item B<-out filename>
112 This specifies the output filename to write to or standard output by
118 This affects any signing or display option that uses a message
119 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options.
120 Any digest supported by the OpenSSL B<dgst> command can be used.
121 If not specified then SHA1 is used with B<-fingerprint> or
122 the default digest for the signing algorithm is used, typically SHA256.
124 =item B<-rand file...>
126 A file or files containing random data used to seed the random number
128 Multiple files can be specified separated by an OS-dependent character.
129 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
132 =item [B<-writerand file>]
134 Writes random data to the specified I<file> upon exit.
135 This can be used with a subsequent B<-rand> flag.
139 Specifying an engine (by its unique B<id> string) will cause B<x509>
140 to attempt to obtain a functional reference to the specified engine,
141 thus initialising it if needed. The engine will then be set as the default
142 for all available algorithms.
144 =item B<-preserve_dates>
146 When signing a certificate, preserve the "notBefore" and "notAfter" dates
147 instead of adjusting them to current time and duration.
148 Cannot be used with the B<-days> option.
152 =head2 Display Options
154 Note: the B<-alias> and B<-purpose> options are also display options
155 but are described in the B<TRUST SETTINGS> section.
161 Prints out the certificate in text form. Full details are output including the
162 public key, signature algorithms, issuer and subject names, serial number
163 any extensions present and any trust settings.
165 =item B<-ext extensions>
167 Prints out the certificate extensions in text form. Extensions are specified
168 with a comma separated string, e.g., "subjectAltName,subjectKeyIdentifier".
169 See the L<x509v3_config(5)> manual page for the extension names.
171 =item B<-certopt option>
173 Customise the output format used with B<-text>. The B<option> argument
174 can be a single option or multiple options separated by commas. The
175 B<-certopt> switch may be also be used more than once to set multiple
176 options. See the B<TEXT OPTIONS> section for more information.
180 This option prevents output of the encoded version of the certificate.
184 Outputs the certificate's SubjectPublicKeyInfo block in PEM format.
188 This option prints out the value of the modulus of the public key
189 contained in the certificate.
193 Outputs the certificate serial number.
195 =item B<-subject_hash>
197 Outputs the "hash" of the certificate subject name. This is used in OpenSSL to
198 form an index to allow certificates in a directory to be looked up by subject
201 =item B<-issuer_hash>
203 Outputs the "hash" of the certificate issuer name.
207 Outputs the OCSP hash values for the subject name and public key.
211 Synonym for "-subject_hash" for backward compatibility reasons.
213 =item B<-subject_hash_old>
215 Outputs the "hash" of the certificate subject name using the older algorithm
216 as used by OpenSSL before version 1.0.0.
218 =item B<-issuer_hash_old>
220 Outputs the "hash" of the certificate issuer name using the older algorithm
221 as used by OpenSSL before version 1.0.0.
225 Outputs the subject name.
229 Outputs the issuer name.
231 =item B<-nameopt option>
233 Option which determines how the subject or issuer names are displayed. The
234 B<option> argument can be a single option or multiple options separated by
235 commas. Alternatively the B<-nameopt> switch may be used more than once to
236 set multiple options. See the B<NAME OPTIONS> section for more information.
240 Outputs the email address(es) if any.
244 Outputs the OCSP responder address(es) if any.
248 Prints out the start date of the certificate, that is the notBefore date.
252 Prints out the expiry date of the certificate, that is the notAfter date.
256 Prints out the start and expiry dates of a certificate.
258 =item B<-checkend arg>
260 Checks if the certificate expires within the next B<arg> seconds and exits
261 non-zero if yes it will expire or zero if not.
263 =item B<-fingerprint>
265 Calculates and outputs the digest of the DER encoded version of the entire
266 certificate (see digest options).
267 This is commonly called a "fingerprint". Because of the nature of message
268 digests, the fingerprint of a certificate is unique to that certificate and
269 two certificates with the same fingerprint can be considered to be the same.
273 This outputs the certificate in the form of a C source file.
277 =head2 Trust Settings
279 A B<trusted certificate> is an ordinary certificate which has several
280 additional pieces of information attached to it such as the permitted
281 and prohibited uses of the certificate and an "alias".
283 Normally when a certificate is being verified at least one certificate
284 must be "trusted". By default a trusted certificate must be stored
285 locally and must be a root CA: any certificate chain ending in this CA
286 is then usable for any purpose.
288 Trust settings currently are only used with a root CA. They allow a finer
289 control over the purposes the root CA can be used for. For example a CA
290 may be trusted for SSL client but not SSL server use.
292 See the description of the B<verify> utility for more information on the
293 meaning of trust settings.
295 Future versions of OpenSSL will recognize trust settings on any
296 certificate: not just root CAs.
303 This causes B<x509> to output a B<trusted> certificate. An ordinary
304 or trusted certificate can be input but by default an ordinary
305 certificate is output and any trust settings are discarded. With the
306 B<-trustout> option a trusted certificate is output. A trusted
307 certificate is automatically output if any trust settings are modified.
309 =item B<-setalias arg>
311 Sets the alias of the certificate. This will allow the certificate
312 to be referred to using a nickname for example "Steve's Certificate".
316 Outputs the certificate alias, if any.
320 Clears all the permitted or trusted uses of the certificate.
324 Clears all the prohibited or rejected uses of the certificate.
326 =item B<-addtrust arg>
328 Adds a trusted certificate use.
329 Any object name can be used here but currently only B<clientAuth> (SSL client
330 use), B<serverAuth> (SSL server use), B<emailProtection> (S/MIME email) and
331 B<anyExtendedKeyUsage> are used.
332 As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or
333 enables all purposes when trusted.
334 Other OpenSSL applications may define additional uses.
336 =item B<-addreject arg>
338 Adds a prohibited use. It accepts the same values as the B<-addtrust>
343 This option performs tests on the certificate extensions and outputs
344 the results. For a more complete description see the B<CERTIFICATE
349 =head2 Signing Options
351 The B<x509> utility can be used to sign certificates and requests: it
352 can thus behave like a "mini CA".
356 =item B<-signkey filename>
358 This option causes the input file to be self signed using the supplied
361 It sets the issuer name to the subject name (i.e., makes it self-issued)
362 and changes the public key to the supplied value (unless overridden by
363 B<-force_pubkey>). It sets the validity start date to the current time
364 and the end date to a value determined by the B<-days> option.
365 It retains any certificate extensions unless the B<-clrext> option is supplied;
366 this includes, for example, any existing key identifier extensions.
368 =item B<-sigopt nm:v>
370 Pass options to the signature algorithm during sign or verify operations.
371 Names and values of these options are algorithm-specific.
375 The key password source. For more information about the format of B<arg>
376 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
380 Delete any extensions from a certificate. This option is used when a
381 certificate is being created from another certificate (for example with
382 the B<-signkey> or the B<-CA> options). Normally all extensions are
385 =item B<-keyform PEM|DER>
387 Specifies the format (DER or PEM) of the private key file used in the
392 Specifies the number of days to make a certificate valid for. The default
393 is 30 days. Cannot be used with the B<-preserve_dates> option.
397 Converts a certificate into a certificate request. The B<-signkey> option
398 is used to pass the required private key.
402 By default a certificate is expected on input. With this option a
403 certificate request is expected instead.
405 =item B<-set_serial n>
407 Specifies the serial number to use. This option can be used with either
408 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
409 option the serial number file (as specified by the B<-CAserial> or
410 B<-CAcreateserial> options) is not used.
412 The serial number can be decimal or hex (if preceded by B<0x>).
414 =item B<-CA filename>
416 Specifies the CA certificate to be used for signing. When this option is
417 present B<x509> behaves like a "mini CA". The input file is signed by this
418 CA using this option: that is its issuer name is set to the subject name
419 of the CA and it is digitally signed using the CAs private key.
421 This option is normally combined with the B<-req> option. Without the
422 B<-req> option the input is a certificate which must be self signed.
424 =item B<-CAkey filename>
426 Sets the CA private key to sign a certificate with. If this option is
427 not specified then it is assumed that the CA private key is present in
428 the CA certificate file.
430 =item B<-CAserial filename>
432 Sets the CA serial number file to use.
434 When the B<-CA> option is used to sign a certificate it uses a serial
435 number specified in a file. This file consists of one line containing
436 an even number of hex digits with the serial number to use. After each
437 use the serial number is incremented and written out to the file again.
439 The default filename consists of the CA certificate file base name with
440 ".srl" appended. For example if the CA certificate file is called
441 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
443 =item B<-CAcreateserial>
445 With this option the CA serial number file is created if it does not exist:
446 it will contain the serial number "02" and the certificate being signed will
447 have the 1 as its serial number. If the B<-CA> option is specified
448 and the serial number file does not exist a random number is generated;
449 this is the recommended practice.
451 =item B<-extfile filename>
453 File containing certificate extensions to use. If not specified then
454 no extensions are added to the certificate.
456 =item B<-extensions section>
458 The section to add certificate extensions from. If this option is not
459 specified then the extensions should either be contained in the unnamed
460 (default) section or the default section should contain a variable called
461 "extensions" which contains the section to use. See the
462 L<x509v3_config(5)> manual page for details of the
463 extension section format.
467 Generate a certificate from scratch, not using an input certificate
468 or certificate request. So the B<-in> option must not be used in this case.
469 Instead, the B<-subj> and <-force_pubkey> options need to be given.
471 =item B<-force_pubkey filename>
473 When a certificate is created set its public key to the key in B<filename>
474 instead of the key contained in the input or given with the B<-signkey> option.
476 This option is useful for creating self-issued certificates that are not
477 self-signed, for instance when the key cannot be used for signing, such as DH.
478 It can also be used in conjunction with b<-new> and B<-subj> to directly
479 generate a certificate containing any desired public key.
481 The format of the key file can be specified using the B<-keyform> option.
485 When a certificate is created set its subject name to the given value.
486 The arg must be formatted as I</type0=value0/type1=value1/type2=...>.
487 Keyword characters may be escaped by \ (backslash), and whitespace is retained.
488 Empty values are permitted, but the corresponding type will not be included
489 in the certificate. Giving a single I</> will lead to an empty sequence of RDNs
492 Unless the B<-CA> option is given the issuer is set to the same value.
494 This option can be used in conjunction with the B<-force_pubkey> option
495 to create a certificate even without providing an input certificate
496 or certificate request.
502 The B<nameopt> command line switch determines how the subject and issuer
503 names are displayed. If no B<nameopt> switch is present the default "oneline"
504 format is used which is compatible with previous versions of OpenSSL.
505 Each option is described in detail below, all options can be preceded by
506 a B<-> to turn the option off. Only the first four will normally be used.
516 Displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
517 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
518 B<sep_comma_plus>, B<dn_rev> and B<sname>.
522 A oneline format which is more readable than RFC2253. It is equivalent to
523 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
524 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
525 options. This is the I<default> of no name options are given explicitly.
529 A multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
530 B<space_eq>, B<lname> and B<align>.
534 Escape the "special" characters required by RFC2253 in a field. That is
535 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
536 and a space character at the beginning or end of a string.
540 Escape the "special" characters required by RFC2254 in a field. That is
541 the B<NUL> character as well as and B<()*>.
545 Escape control characters. That is those with ASCII values less than
546 0x20 (space) and the delete (0x7f) character. They are escaped using the
547 RFC2253 \XX notation (where XX are two hex digits representing the
552 Escape characters with the MSB set, that is with ASCII values larger than
557 Escapes some characters by surrounding the whole string with B<"> characters,
558 without the option all escaping is done with the B<\> character.
562 Convert all strings to UTF8 format first. This is required by RFC2253. If
563 you are lucky enough to have a UTF8 compatible terminal then the use
564 of this option (and B<not> setting B<esc_msb>) may result in the correct
565 display of multibyte (international) characters. Is this option is not
566 present then multibyte characters larger than 0xff will be represented
567 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
568 Also if this option is off any UTF8Strings will be converted to their
569 character form first.
573 This option does not attempt to interpret multibyte characters in any
574 way. That is their content octets are merely dumped as though one octet
575 represents each character. This is useful for diagnostic purposes but
576 will result in rather odd looking output.
580 Show the type of the ASN1 character string. The type precedes the
581 field contents. For example "BMPSTRING: Hello World".
585 When this option is set any fields that need to be hexdumped will
586 be dumped using the DER encoding of the field. Otherwise just the
587 content octets will be displayed. Both options use the RFC2253
592 Dump non character string types (for example OCTET STRING) if this
593 option is not set then non character string types will be displayed
594 as though each content octet represents a single character.
598 Dump all fields. This option when used with B<dump_der> allows the
599 DER encoding of the structure to be unambiguously determined.
601 =item B<dump_unknown>
603 Dump any field whose OID is not recognised by OpenSSL.
605 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
608 These options determine the field separators. The first character is
609 between Relative Distinguished Names (RDNs) and the second is between
610 multiple Attribute Value Assertions (AVAs, multiple AVAs are
611 very rare and their use is discouraged). The options ending in
612 "space" additionally place a space after the separator to make it
613 more readable. The B<sep_multiline> uses a linefeed character for
614 the RDN separator and a spaced B<+> for the AVA separator. It also
615 indents the fields by four characters. If no field separator is specified
616 then B<sep_comma_plus_space> is used by default.
620 Reverse the fields of the DN. This is required by RFC2253. As a side
621 effect this also reverses the order of multiple AVAs but this is
624 =item B<nofname>, B<sname>, B<lname>, B<oid>
626 These options alter how the field name is displayed. B<nofname> does
627 not display the field at all. B<sname> uses the "short name" form
628 (CN for commonName for example). B<lname> uses the long form.
629 B<oid> represents the OID in numerical form and is useful for
634 Align field values for a more readable output. Only usable with
639 Places spaces round the B<=> character which follows the field
646 As well as customising the name output format, it is also possible to
647 customise the actual fields printed using the B<certopt> options when
648 the B<text> option is present. The default behaviour is to print all fields.
654 Use the old format. This is equivalent to specifying no output options at all.
658 Don't print header information: that is the lines saying "Certificate"
663 Don't print out the version number.
667 Don't print out the serial number.
671 Don't print out the signature algorithm used.
675 Don't print the validity, that is the B<notBefore> and B<notAfter> fields.
679 Don't print out the subject name.
683 Don't print out the issuer name.
687 Don't print out the public key.
691 Don't give a hexadecimal dump of the certificate signature.
695 Don't print out certificate trust information.
697 =item B<no_extensions>
699 Don't print out any X509V3 extensions.
703 Retain default extension behaviour: attempt to print out unsupported
704 certificate extensions.
708 Print an error message for unsupported certificate extensions.
712 ASN1 parse unsupported extensions.
716 Hex dump unsupported extensions.
720 The value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
721 B<no_header>, and B<no_version>.
727 Note: in these examples the '\' means the example should be all on one
730 Display the contents of a certificate:
732 openssl x509 -in cert.pem -noout -text
734 Display the "Subject Alternative Name" extension of a certificate:
736 openssl x509 -in cert.pem -noout -ext subjectAltName
738 Display more extensions of a certificate:
740 openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType
742 Display the certificate serial number:
744 openssl x509 -in cert.pem -noout -serial
746 Display the certificate subject name:
748 openssl x509 -in cert.pem -noout -subject
750 Display the certificate subject name in RFC2253 form:
752 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
754 Display the certificate subject name in oneline form on a terminal
757 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
759 Display the certificate SHA1 fingerprint:
761 openssl x509 -sha1 -in cert.pem -noout -fingerprint
763 Convert a certificate from PEM to DER format:
765 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
767 Convert a certificate to a certificate request:
769 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
771 Convert a certificate request into a self signed certificate using
774 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
775 -signkey key.pem -out cacert.pem
777 Sign a certificate request using the CA certificate above and add user
778 certificate extensions:
780 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
781 -CA cacert.pem -CAkey key.pem -CAcreateserial
784 Set a certificate to be trusted for SSL client use and change set its alias to
787 openssl x509 -in cert.pem -addtrust clientAuth \
788 -setalias "Steve's Class 1 CA" -out trust.pem
792 The PEM format uses the header and footer lines:
794 -----BEGIN CERTIFICATE-----
795 -----END CERTIFICATE-----
797 it will also handle files containing:
799 -----BEGIN X509 CERTIFICATE-----
800 -----END X509 CERTIFICATE-----
802 Trusted certificates have the lines
804 -----BEGIN TRUSTED CERTIFICATE-----
805 -----END TRUSTED CERTIFICATE-----
807 The conversion to UTF8 format used with the name options assumes that
808 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
809 and MSIE do this as do many certificates. So although this is incorrect
810 it is more likely to display the majority of certificates correctly.
812 The B<-email> option searches the subject name and the subject alternative
813 name extension. Only unique email addresses will be printed out: it will
814 not print the same address more than once.
816 =head1 CERTIFICATE EXTENSIONS
818 The B<-purpose> option checks the certificate extensions and determines
819 what the certificate can be used for. The actual checks done are rather
820 complex and include various hacks and workarounds to handle broken
821 certificates and software.
823 The same code is used when verifying untrusted certificates in chains
824 so this section is useful if a chain is rejected by the verify code.
826 The basicConstraints extension CA flag is used to determine whether the
827 certificate can be used as a CA. If the CA flag is true then it is a CA,
828 if the CA flag is false then it is not a CA. B<All> CAs should have the
831 If the basicConstraints extension is absent then the certificate is
832 considered to be a "possible CA" other extensions are checked according
833 to the intended use of the certificate. A warning is given in this case
834 because the certificate should really not be regarded as a CA: however
835 it is allowed to be a CA to work around some broken software.
837 If the certificate is a V1 certificate (and thus has no extensions) and
838 it is self signed it is also assumed to be a CA but a warning is again
839 given: this is to work around the problem of Verisign roots which are V1
840 self signed certificates.
842 If the keyUsage extension is present then additional restraints are
843 made on the uses of the certificate. A CA certificate B<must> have the
844 keyCertSign bit set if the keyUsage extension is present.
846 The extended key usage extension places additional restrictions on the
847 certificate uses. If this extension is present (whether critical or not)
848 the key can only be used for the purposes specified.
850 A complete description of each test is given below. The comments about
851 basicConstraints and keyUsage and V1 certificates above apply to B<all>
859 The extended key usage extension must be absent or include the "web client
860 authentication" OID. keyUsage must be absent or it must have the
861 digitalSignature bit set. Netscape certificate type must be absent or it must
862 have the SSL client bit set.
864 =item B<SSL Client CA>
866 The extended key usage extension must be absent or include the "web client
867 authentication" OID. Netscape certificate type must be absent or it must have
868 the SSL CA bit set: this is used as a work around if the basicConstraints
873 The extended key usage extension must be absent or include the "web server
874 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
875 must have the digitalSignature, the keyEncipherment set or both bits set.
876 Netscape certificate type must be absent or have the SSL server bit set.
878 =item B<SSL Server CA>
880 The extended key usage extension must be absent or include the "web server
881 authentication" and/or one of the SGC OIDs. Netscape certificate type must
882 be absent or the SSL CA bit must be set: this is used as a work around if the
883 basicConstraints extension is absent.
885 =item B<Netscape SSL Server>
887 For Netscape SSL clients to connect to an SSL server it must have the
888 keyEncipherment bit set if the keyUsage extension is present. This isn't
889 always valid because some cipher suites use the key for digital signing.
890 Otherwise it is the same as a normal SSL server.
892 =item B<Common S/MIME Client Tests>
894 The extended key usage extension must be absent or include the "email
895 protection" OID. Netscape certificate type must be absent or should have the
896 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
897 then the SSL client bit is tolerated as an alternative but a warning is shown:
898 this is because some Verisign certificates don't set the S/MIME bit.
900 =item B<S/MIME Signing>
902 In addition to the common S/MIME client tests the digitalSignature bit or
903 the nonRepudiation bit must be set if the keyUsage extension is present.
905 =item B<S/MIME Encryption>
907 In addition to the common S/MIME tests the keyEncipherment bit must be set
908 if the keyUsage extension is present.
912 The extended key usage extension must be absent or include the "email
913 protection" OID. Netscape certificate type must be absent or must have the
914 S/MIME CA bit set: this is used as a work around if the basicConstraints
919 The keyUsage extension must be absent or it must have the CRL signing bit
922 =item B<CRL Signing CA>
924 The normal CA tests apply. Except in this case the basicConstraints extension
931 Extensions in certificates are not transferred to certificate requests and
934 It is possible to produce invalid certificates or requests by specifying the
935 wrong private key or using inconsistent options in some cases: these should
938 There should be options to explicitly set such things as start and end
939 dates rather than an offset from the current time.
943 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
944 L<gendsa(1)>, L<verify(1)>,
949 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
950 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
951 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
952 canonical version of the DN using SHA1. This means that any directories using
953 the old form must have their links rebuilt using B<c_rehash> or similar.
957 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
959 Licensed under the Apache License 2.0 (the "License"). You may not use
960 this file except in compliance with the License. You can obtain a copy
961 in the file LICENSE in the source distribution or at
962 L<https://www.openssl.org/source/license.html>.