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>]
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.
369 The key password source. For more information about the format of B<arg>
370 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
374 Delete any extensions from a certificate. This option is used when a
375 certificate is being created from another certificate (for example with
376 the B<-signkey> or the B<-CA> options). Normally all extensions are
379 =item B<-keyform PEM|DER>
381 Specifies the format (DER or PEM) of the private key file used in the
386 Specifies the number of days to make a certificate valid for. The default
387 is 30 days. Cannot be used with the B<-preserve_dates> option.
391 Converts a certificate into a certificate request. The B<-signkey> option
392 is used to pass the required private key.
396 By default a certificate is expected on input. With this option a
397 certificate request is expected instead.
399 =item B<-set_serial n>
401 Specifies the serial number to use. This option can be used with either
402 the B<-signkey> or B<-CA> options. If used in conjunction with the B<-CA>
403 option the serial number file (as specified by the B<-CAserial> or
404 B<-CAcreateserial> options) is not used.
406 The serial number can be decimal or hex (if preceded by B<0x>).
408 =item B<-CA filename>
410 Specifies the CA certificate to be used for signing. When this option is
411 present B<x509> behaves like a "mini CA". The input file is signed by this
412 CA using this option: that is its issuer name is set to the subject name
413 of the CA and it is digitally signed using the CAs private key.
415 This option is normally combined with the B<-req> option. Without the
416 B<-req> option the input is a certificate which must be self signed.
418 =item B<-CAkey filename>
420 Sets the CA private key to sign a certificate with. If this option is
421 not specified then it is assumed that the CA private key is present in
422 the CA certificate file.
424 =item B<-CAserial filename>
426 Sets the CA serial number file to use.
428 When the B<-CA> option is used to sign a certificate it uses a serial
429 number specified in a file. This file consists of one line containing
430 an even number of hex digits with the serial number to use. After each
431 use the serial number is incremented and written out to the file again.
433 The default filename consists of the CA certificate file base name with
434 ".srl" appended. For example if the CA certificate file is called
435 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
437 =item B<-CAcreateserial>
439 With this option the CA serial number file is created if it does not exist:
440 it will contain the serial number "02" and the certificate being signed will
441 have the 1 as its serial number. If the B<-CA> option is specified
442 and the serial number file does not exist a random number is generated;
443 this is the recommended practice.
445 =item B<-extfile filename>
447 File containing certificate extensions to use. If not specified then
448 no extensions are added to the certificate.
450 =item B<-extensions section>
452 The section to add certificate extensions from. If this option is not
453 specified then the extensions should either be contained in the unnamed
454 (default) section or the default section should contain a variable called
455 "extensions" which contains the section to use. See the
456 L<x509v3_config(5)> manual page for details of the
457 extension section format.
461 Generate a certificate from scratch, not using an input certificate
462 or certificate request. So the B<-in> option must not be used in this case.
463 Instead, the B<-subj> and <-force_pubkey> options need to be given.
465 =item B<-force_pubkey filename>
467 When a certificate is created set its public key to the key in B<filename>
468 instead of the key contained in the input or given with the B<-signkey> option.
470 This option is useful for creating self-issued certificates that are not
471 self-signed, for instance when the key cannot be used for signing, such as DH.
472 It can also be used in conjunction with b<-new> and B<-subj> to directly
473 generate a certificate containing any desired public key.
475 The format of the key file can be specified using the B<-keyform> option.
479 When a certificate is created set its subject name to the given value.
480 The arg must be formatted as I</type0=value0/type1=value1/type2=...>.
481 Keyword characters may be escaped by \ (backslash), and whitespace is retained.
482 Empty values are permitted, but the corresponding type will not be included
483 in the certificate. Giving a single I</> will lead to an empty sequence of RDNs
486 Unless the B<-CA> option is given the issuer is set to the same value.
488 This option can be used in conjunction with the B<-force_pubkey> option
489 to create a certificate even without providing an input certificate
490 or certificate request.
496 The B<nameopt> command line switch determines how the subject and issuer
497 names are displayed. If no B<nameopt> switch is present the default "oneline"
498 format is used which is compatible with previous versions of OpenSSL.
499 Each option is described in detail below, all options can be preceded by
500 a B<-> to turn the option off. Only the first four will normally be used.
510 Displays names compatible with RFC2253 equivalent to B<esc_2253>, B<esc_ctrl>,
511 B<esc_msb>, B<utf8>, B<dump_nostr>, B<dump_unknown>, B<dump_der>,
512 B<sep_comma_plus>, B<dn_rev> and B<sname>.
516 A oneline format which is more readable than RFC2253. It is equivalent to
517 specifying the B<esc_2253>, B<esc_ctrl>, B<esc_msb>, B<utf8>, B<dump_nostr>,
518 B<dump_der>, B<use_quote>, B<sep_comma_plus_space>, B<space_eq> and B<sname>
519 options. This is the I<default> of no name options are given explicitly.
523 A multiline format. It is equivalent B<esc_ctrl>, B<esc_msb>, B<sep_multiline>,
524 B<space_eq>, B<lname> and B<align>.
528 Escape the "special" characters required by RFC2253 in a field. That is
529 B<,+"E<lt>E<gt>;>. Additionally B<#> is escaped at the beginning of a string
530 and a space character at the beginning or end of a string.
534 Escape the "special" characters required by RFC2254 in a field. That is
535 the B<NUL> character as well as and B<()*>.
539 Escape control characters. That is those with ASCII values less than
540 0x20 (space) and the delete (0x7f) character. They are escaped using the
541 RFC2253 \XX notation (where XX are two hex digits representing the
546 Escape characters with the MSB set, that is with ASCII values larger than
551 Escapes some characters by surrounding the whole string with B<"> characters,
552 without the option all escaping is done with the B<\> character.
556 Convert all strings to UTF8 format first. This is required by RFC2253. If
557 you are lucky enough to have a UTF8 compatible terminal then the use
558 of this option (and B<not> setting B<esc_msb>) may result in the correct
559 display of multibyte (international) characters. Is this option is not
560 present then multibyte characters larger than 0xff will be represented
561 using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits.
562 Also if this option is off any UTF8Strings will be converted to their
563 character form first.
567 This option does not attempt to interpret multibyte characters in any
568 way. That is their content octets are merely dumped as though one octet
569 represents each character. This is useful for diagnostic purposes but
570 will result in rather odd looking output.
574 Show the type of the ASN1 character string. The type precedes the
575 field contents. For example "BMPSTRING: Hello World".
579 When this option is set any fields that need to be hexdumped will
580 be dumped using the DER encoding of the field. Otherwise just the
581 content octets will be displayed. Both options use the RFC2253
586 Dump non character string types (for example OCTET STRING) if this
587 option is not set then non character string types will be displayed
588 as though each content octet represents a single character.
592 Dump all fields. This option when used with B<dump_der> allows the
593 DER encoding of the structure to be unambiguously determined.
595 =item B<dump_unknown>
597 Dump any field whose OID is not recognised by OpenSSL.
599 =item B<sep_comma_plus>, B<sep_comma_plus_space>, B<sep_semi_plus_space>,
602 These options determine the field separators. The first character is
603 between Relative Distinguished Names (RDNs) and the second is between
604 multiple Attribute Value Assertions (AVAs, multiple AVAs are
605 very rare and their use is discouraged). The options ending in
606 "space" additionally place a space after the separator to make it
607 more readable. The B<sep_multiline> uses a linefeed character for
608 the RDN separator and a spaced B<+> for the AVA separator. It also
609 indents the fields by four characters. If no field separator is specified
610 then B<sep_comma_plus_space> is used by default.
614 Reverse the fields of the DN. This is required by RFC2253. As a side
615 effect this also reverses the order of multiple AVAs but this is
618 =item B<nofname>, B<sname>, B<lname>, B<oid>
620 These options alter how the field name is displayed. B<nofname> does
621 not display the field at all. B<sname> uses the "short name" form
622 (CN for commonName for example). B<lname> uses the long form.
623 B<oid> represents the OID in numerical form and is useful for
628 Align field values for a more readable output. Only usable with
633 Places spaces round the B<=> character which follows the field
640 As well as customising the name output format, it is also possible to
641 customise the actual fields printed using the B<certopt> options when
642 the B<text> option is present. The default behaviour is to print all fields.
648 Use the old format. This is equivalent to specifying no output options at all.
652 Don't print header information: that is the lines saying "Certificate"
657 Don't print out the version number.
661 Don't print out the serial number.
665 Don't print out the signature algorithm used.
669 Don't print the validity, that is the B<notBefore> and B<notAfter> fields.
673 Don't print out the subject name.
677 Don't print out the issuer name.
681 Don't print out the public key.
685 Don't give a hexadecimal dump of the certificate signature.
689 Don't print out certificate trust information.
691 =item B<no_extensions>
693 Don't print out any X509V3 extensions.
697 Retain default extension behaviour: attempt to print out unsupported
698 certificate extensions.
702 Print an error message for unsupported certificate extensions.
706 ASN1 parse unsupported extensions.
710 Hex dump unsupported extensions.
714 The value used by the B<ca> utility, equivalent to B<no_issuer>, B<no_pubkey>,
715 B<no_header>, and B<no_version>.
721 Note: in these examples the '\' means the example should be all on one
724 Display the contents of a certificate:
726 openssl x509 -in cert.pem -noout -text
728 Display the "Subject Alternative Name" extension of a certificate:
730 openssl x509 -in cert.pem -noout -ext subjectAltName
732 Display more extensions of a certificate:
734 openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType
736 Display the certificate serial number:
738 openssl x509 -in cert.pem -noout -serial
740 Display the certificate subject name:
742 openssl x509 -in cert.pem -noout -subject
744 Display the certificate subject name in RFC2253 form:
746 openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
748 Display the certificate subject name in oneline form on a terminal
751 openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb
753 Display the certificate SHA1 fingerprint:
755 openssl x509 -sha1 -in cert.pem -noout -fingerprint
757 Convert a certificate from PEM to DER format:
759 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
761 Convert a certificate to a certificate request:
763 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
765 Convert a certificate request into a self signed certificate using
768 openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \
769 -signkey key.pem -out cacert.pem
771 Sign a certificate request using the CA certificate above and add user
772 certificate extensions:
774 openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \
775 -CA cacert.pem -CAkey key.pem -CAcreateserial
778 Set a certificate to be trusted for SSL client use and change set its alias to
781 openssl x509 -in cert.pem -addtrust clientAuth \
782 -setalias "Steve's Class 1 CA" -out trust.pem
786 The PEM format uses the header and footer lines:
788 -----BEGIN CERTIFICATE-----
789 -----END CERTIFICATE-----
791 it will also handle files containing:
793 -----BEGIN X509 CERTIFICATE-----
794 -----END X509 CERTIFICATE-----
796 Trusted certificates have the lines
798 -----BEGIN TRUSTED CERTIFICATE-----
799 -----END TRUSTED CERTIFICATE-----
801 The conversion to UTF8 format used with the name options assumes that
802 T61Strings use the ISO8859-1 character set. This is wrong but Netscape
803 and MSIE do this as do many certificates. So although this is incorrect
804 it is more likely to display the majority of certificates correctly.
806 The B<-email> option searches the subject name and the subject alternative
807 name extension. Only unique email addresses will be printed out: it will
808 not print the same address more than once.
810 =head1 CERTIFICATE EXTENSIONS
812 The B<-purpose> option checks the certificate extensions and determines
813 what the certificate can be used for. The actual checks done are rather
814 complex and include various hacks and workarounds to handle broken
815 certificates and software.
817 The same code is used when verifying untrusted certificates in chains
818 so this section is useful if a chain is rejected by the verify code.
820 The basicConstraints extension CA flag is used to determine whether the
821 certificate can be used as a CA. If the CA flag is true then it is a CA,
822 if the CA flag is false then it is not a CA. B<All> CAs should have the
825 If the basicConstraints extension is absent then the certificate is
826 considered to be a "possible CA" other extensions are checked according
827 to the intended use of the certificate. A warning is given in this case
828 because the certificate should really not be regarded as a CA: however
829 it is allowed to be a CA to work around some broken software.
831 If the certificate is a V1 certificate (and thus has no extensions) and
832 it is self signed it is also assumed to be a CA but a warning is again
833 given: this is to work around the problem of Verisign roots which are V1
834 self signed certificates.
836 If the keyUsage extension is present then additional restraints are
837 made on the uses of the certificate. A CA certificate B<must> have the
838 keyCertSign bit set if the keyUsage extension is present.
840 The extended key usage extension places additional restrictions on the
841 certificate uses. If this extension is present (whether critical or not)
842 the key can only be used for the purposes specified.
844 A complete description of each test is given below. The comments about
845 basicConstraints and keyUsage and V1 certificates above apply to B<all>
853 The extended key usage extension must be absent or include the "web client
854 authentication" OID. keyUsage must be absent or it must have the
855 digitalSignature bit set. Netscape certificate type must be absent or it must
856 have the SSL client bit set.
858 =item B<SSL Client CA>
860 The extended key usage extension must be absent or include the "web client
861 authentication" OID. Netscape certificate type must be absent or it must have
862 the SSL CA bit set: this is used as a work around if the basicConstraints
867 The extended key usage extension must be absent or include the "web server
868 authentication" and/or one of the SGC OIDs. keyUsage must be absent or it
869 must have the digitalSignature, the keyEncipherment set or both bits set.
870 Netscape certificate type must be absent or have the SSL server bit set.
872 =item B<SSL Server CA>
874 The extended key usage extension must be absent or include the "web server
875 authentication" and/or one of the SGC OIDs. Netscape certificate type must
876 be absent or the SSL CA bit must be set: this is used as a work around if the
877 basicConstraints extension is absent.
879 =item B<Netscape SSL Server>
881 For Netscape SSL clients to connect to an SSL server it must have the
882 keyEncipherment bit set if the keyUsage extension is present. This isn't
883 always valid because some cipher suites use the key for digital signing.
884 Otherwise it is the same as a normal SSL server.
886 =item B<Common S/MIME Client Tests>
888 The extended key usage extension must be absent or include the "email
889 protection" OID. Netscape certificate type must be absent or should have the
890 S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type
891 then the SSL client bit is tolerated as an alternative but a warning is shown:
892 this is because some Verisign certificates don't set the S/MIME bit.
894 =item B<S/MIME Signing>
896 In addition to the common S/MIME client tests the digitalSignature bit or
897 the nonRepudiation bit must be set if the keyUsage extension is present.
899 =item B<S/MIME Encryption>
901 In addition to the common S/MIME tests the keyEncipherment bit must be set
902 if the keyUsage extension is present.
906 The extended key usage extension must be absent or include the "email
907 protection" OID. Netscape certificate type must be absent or must have the
908 S/MIME CA bit set: this is used as a work around if the basicConstraints
913 The keyUsage extension must be absent or it must have the CRL signing bit
916 =item B<CRL Signing CA>
918 The normal CA tests apply. Except in this case the basicConstraints extension
925 Extensions in certificates are not transferred to certificate requests and
928 It is possible to produce invalid certificates or requests by specifying the
929 wrong private key or using inconsistent options in some cases: these should
932 There should be options to explicitly set such things as start and end
933 dates rather than an offset from the current time.
937 L<req(1)>, L<ca(1)>, L<genrsa(1)>,
938 L<gendsa(1)>, L<verify(1)>,
943 The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
944 before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
945 of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
946 canonical version of the DN using SHA1. This means that any directories using
947 the old form must have their links rebuilt using B<c_rehash> or similar.
951 Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
953 Licensed under the Apache License 2.0 (the "License"). You may not use
954 this file except in compliance with the License. You can obtain a copy
955 in the file LICENSE in the source distribution or at
956 L<https://www.openssl.org/source/license.html>.