1X509V3_CONFIG(5ossl)                OpenSSL               X509V3_CONFIG(5ossl)
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NAME

6       x509v3_config - X509 V3 certificate extension configuration format
7

DESCRIPTION

9       Several OpenSSL commands can add extensions to a certificate or
10       certificate request based on the contents of a configuration file and
11       CLI options such as -addext.  The syntax of configuration files is
12       described in config(5).  The commands typically have an option to
13       specify the name of the configuration file, and a section within that
14       file; see the documentation of the individual command for details.
15
16       This page uses extensions as the name of the section, when needed in
17       examples.
18
19       Each entry in the extension section takes the form:
20
21        name = [critical, ]value(s)
22
23       If critical is present then the extension will be marked as critical.
24
25       If multiple entries are processed for the same extension name, later
26       entries override earlier ones with the same name.
27
28       The format of values depends on the value of name, many have a type-
29       value pairing where the type and value are separated by a colon.  There
30       are four main types of extension:
31
32        string
33        multi-valued
34        raw
35        arbitrary
36
37       Each is described in the following paragraphs.
38
39       String extensions simply have a string which contains either the value
40       itself or how it is obtained.
41
42       Multi-valued extensions have a short form and a long form. The short
43       form is a comma-separated list of names and values:
44
45        basicConstraints = critical, CA:true, pathlen:1
46
47       The long form allows the values to be placed in a separate section:
48
49        [extensions]
50        basicConstraints = critical, @basic_constraints
51
52        [basic_constraints]
53        CA = true
54        pathlen = 1
55
56       Both forms are equivalent.
57
58       If an extension is multi-value and a field value must contain a comma
59       the long form must be used otherwise the comma would be misinterpreted
60       as a field separator. For example:
61
62        subjectAltName = URI:ldap://somehost.com/CN=foo,OU=bar
63
64       will produce an error but the equivalent form:
65
66        [extensions]
67        subjectAltName = @subject_alt_section
68
69        [subject_alt_section]
70        subjectAltName = URI:ldap://somehost.com/CN=foo,OU=bar
71
72       is valid.
73
74       OpenSSL does not support multiple occurrences of the same field within
75       a section. In this example:
76
77        [extensions]
78        subjectAltName = @alt_section
79
80        [alt_section]
81        email = steve@example.com
82        email = steve@example.org
83
84       will only recognize the last value.  To specify multiple values append
85       a numeric identifier, as shown here:
86
87        [extensions]
88        subjectAltName = @alt_section
89
90        [alt_section]
91        email.1 = steve@example.com
92        email.2 = steve@example.org
93
94       The syntax of raw extensions is defined by the source code that parses
95       the extension but should be documened.  See "Certificate Policies" for
96       an example of a raw extension.
97
98       If an extension type is unsupported, then the arbitrary extension
99       syntax must be used, see the "ARBITRARY EXTENSIONS" section for more
100       details.
101

STANDARD EXTENSIONS

103       The following sections describe the syntax of each supported extension.
104       They do not define the semantics of the extension.
105
106   Basic Constraints
107       This is a multi-valued extension which indicates whether a certificate
108       is a CA certificate. The first value is CA followed by TRUE or FALSE.
109       If CA is TRUE then an optional pathlen name followed by a nonnegative
110       value can be included.
111
112       For example:
113
114        basicConstraints = CA:TRUE
115
116        basicConstraints = CA:FALSE
117
118        basicConstraints = critical, CA:TRUE, pathlen:1
119
120       A CA certificate must include the basicConstraints name with the CA
121       parameter set to TRUE. An end-user certificate must either have
122       CA:FALSE or omit the extension entirely.  The pathlen parameter
123       specifies the maximum number of CAs that can appear below this one in a
124       chain. A pathlen of zero means the CA cannot sign any sub-CA's, and can
125       only sign end-entity certificates.
126
127   Key Usage
128       Key usage is a multi-valued extension consisting of a list of names of
129       the permitted key usages.  The defined values are: "digitalSignature",
130       "nonRepudiation", "keyEncipherment", "dataEncipherment",
131       "keyAgreement", "keyCertSign", "cRLSign", "encipherOnly", and
132       "decipherOnly".
133
134       Examples:
135
136        keyUsage = digitalSignature, nonRepudiation
137
138        keyUsage = critical, keyCertSign
139
140   Extended Key Usage
141       This extension consists of a list of values indicating purposes for
142       which the certificate public key can be used.  Each value can be either
143       a short text name or an OID.  The following text names, and their
144       intended meaning, are known:
145
146        Value                  Meaning according to RFC 5280 etc.
147        -----                  ----------------------------------
148        serverAuth             SSL/TLS WWW Server Authentication
149        clientAuth             SSL/TLS WWW Client Authentication
150        codeSigning            Code Signing
151        emailProtection        E-mail Protection (S/MIME)
152        timeStamping           Trusted Timestamping
153        OCSPSigning            OCSP Signing
154        ipsecIKE               ipsec Internet Key Exchange
155        msCodeInd              Microsoft Individual Code Signing (authenticode)
156        msCodeCom              Microsoft Commercial Code Signing (authenticode)
157        msCTLSign              Microsoft Trust List Signing
158        msEFS                  Microsoft Encrypted File System
159
160       While IETF RFC 5280 says that id-kp-serverAuth and id-kp-clientAuth are
161       only for WWW use, in practice they are used for all kinds of TLS
162       clients and servers, and this is what OpenSSL assumes as well.
163
164       Examples:
165
166        extendedKeyUsage = critical, codeSigning, 1.2.3.4
167
168        extendedKeyUsage = serverAuth, clientAuth
169
170   Subject Key Identifier
171       The SKID extension specification has a value with three choices.  If
172       the value is the word none then no SKID extension will be included.  If
173       the value is the word hash, or by default for the x509, req, and ca
174       apps, the process specified in RFC 5280 section 4.2.1.2. (1) is
175       followed: The keyIdentifier is composed of the 160-bit SHA-1 hash of
176       the value of the BIT STRING subjectPublicKey (excluding the tag,
177       length, and number of unused bits).
178
179       Otherwise, the value must be a hex string (possibly with ":" separating
180       bytes) to output directly, however, this is strongly discouraged.
181
182       Example:
183
184        subjectKeyIdentifier = hash
185
186   Authority Key Identifier
187       The AKID extension specification may have the value none indicating
188       that no AKID shall be included.  Otherwise it may have the value keyid
189       or issuer or both of them, separated by ",".  Either or both can have
190       the option always, indicated by putting a colon ":" between the value
191       and this option.  For self-signed certificates the AKID is suppressed
192       unless always is present.  By default the x509, req, and ca apps behave
193       as if "none" was given for self-signed certificates and "keyid, issuer"
194       otherwise.
195
196       If keyid is present, an attempt is made to copy the subject key
197       identifier (SKID) from the issuer certificate except if the issuer
198       certificate is the same as the current one and it is not self-signed.
199       The hash of the public key related to the signing key is taken as
200       fallback if the issuer certificate is the same as the current
201       certificate.  If always is present but no value can be obtained, an
202       error is returned.
203
204       If issuer is present, and in addition it has the option always
205       specified or keyid is not present, then the issuer DN and serial number
206       are copied from the issuer certificate.
207
208       Examples:
209
210        authorityKeyIdentifier = keyid, issuer
211
212        authorityKeyIdentifier = keyid, issuer:always
213
214   Subject Alternative Name
215       This is a multi-valued extension that supports several types of name
216       identifier, including email (an email address), URI (a uniform resource
217       indicator), DNS (a DNS domain name), RID (a registered ID: OBJECT
218       IDENTIFIER), IP (an IP address), dirName (a distinguished name), and
219       otherName.  The syntax of each is described in the following
220       paragraphs.
221
222       The email option has two special values.  "copy" will automatically
223       include any email addresses contained in the certificate subject name
224       in the extension.  "move" will automatically move any email addresses
225       from the certificate subject name to the extension.
226
227       The IP address used in the IP option can be in either IPv4 or IPv6
228       format.
229
230       The value of dirName is specifies the configuration section containing
231       the distinguished name to use, as a set of name-value pairs.  Multi-
232       valued AVAs can be formed by prefacing the name with a + character.
233
234       The value of otherName can include arbitrary data associated with an
235       OID; the value should be the OID followed by a semicolon and the
236       content in specified using the syntax in ASN1_generate_nconf(3).
237
238       Examples:
239
240        subjectAltName = email:copy, email:my@example.com, URI:http://my.example.com/
241
242        subjectAltName = IP:192.168.7.1
243
244        subjectAltName = IP:13::17
245
246        subjectAltName = email:my@example.com, RID:1.2.3.4
247
248        subjectAltName = otherName:1.2.3.4;UTF8:some other identifier
249
250        [extensions]
251        subjectAltName = dirName:dir_sect
252
253        [dir_sect]
254        C = UK
255        O = My Organization
256        OU = My Unit
257        CN = My Name
258
259       Non-ASCII Email Address conforming the syntax defined in Section 3.3 of
260       RFC 6531 are provided as otherName.SmtpUTF8Mailbox. According to RFC
261       8398, the email address should be provided as UTF8String. To enforce
262       the valid representation in the certificate, the SmtpUTF8Mailbox should
263       be provided as follows
264
265        subjectAltName=@alts
266        [alts]
267        otherName = 1.3.6.1.5.5.7.8.9;FORMAT:UTF8,UTF8String:nonasciiname.example.com
268
269   Issuer Alternative Name
270       This extension supports most of the options of subject alternative
271       name; it does not support email:copy.  It also adds issuer:copy as an
272       allowed value, which copies any subject alternative names from the
273       issuer certificate, if possible.
274
275       Example:
276
277        issuerAltName = issuer:copy
278
279   Authority Info Access
280       This extension gives details about how to retrieve information that
281       related to the certificate that the CA makes available. The syntax is
282       access_id;location, where access_id is an object identifier (although
283       only a few values are well-known) and location has the same syntax as
284       subject alternative name (except that email:copy is not supported).
285
286       Possible values for access_id include OCSP (OCSP responder), caIssuers
287       (CA Issuers), ad_timestamping (AD Time Stamping), AD_DVCS (ad dvcs),
288       caRepository (CA Repository).
289
290       Examples:
291
292        authorityInfoAccess = OCSP;URI:http://ocsp.example.com/,caIssuers;URI:http://myca.example.com/ca.cer
293
294        authorityInfoAccess = OCSP;URI:http://ocsp.example.com/
295
296   CRL distribution points
297       This is a multi-valued extension whose values can be either a name-
298       value pair using the same form as subject alternative name or a single
299       value specifying the section name containing all the distribution point
300       values.
301
302       When a name-value pair is used, a DistributionPoint extension will be
303       set with the given value as the fullName field as the distributionPoint
304       value, and the reasons and cRLIssuer fields will be omitted.
305
306       When a single option is used, the value specifies the section, and that
307       section can have the following items:
308
309       fullname
310           The full name of the distribution point, in the same format as the
311           subject alternative name.
312
313       relativename
314           The value is taken as a distinguished name fragment that is set as
315           the value of the nameRelativeToCRLIssuer field.
316
317       CRLIssuer
318           The value must in the same format as the subject alternative name.
319
320       reasons
321           A multi-value field that contains the reasons for revocation. The
322           recognized values are: "keyCompromise", "CACompromise",
323           "affiliationChanged", "superseded", "cessationOfOperation",
324           "certificateHold", "privilegeWithdrawn", and "AACompromise".
325
326       Only one of fullname or relativename should be specified.
327
328       Simple examples:
329
330        crlDistributionPoints = URI:http://example.com/myca.crl
331
332        crlDistributionPoints = URI:http://example.com/myca.crl, URI:http://example.org/my.crl
333
334       Full distribution point example:
335
336        [extensions]
337        crlDistributionPoints = crldp1_section
338
339        [crldp1_section]
340        fullname = URI:http://example.com/myca.crl
341        CRLissuer = dirName:issuer_sect
342        reasons = keyCompromise, CACompromise
343
344        [issuer_sect]
345        C = UK
346        O = Organisation
347        CN = Some Name
348
349   Issuing Distribution Point
350       This extension should only appear in CRLs. It is a multi-valued
351       extension whose syntax is similar to the "section" pointed to by the
352       CRL distribution points extension. The following names have meaning:
353
354       fullname
355           The full name of the distribution point, in the same format as the
356           subject alternative name.
357
358       relativename
359           The value is taken as a distinguished name fragment that is set as
360           the value of the nameRelativeToCRLIssuer field.
361
362       onlysomereasons
363           A multi-value field that contains the reasons for revocation. The
364           recognized values are: "keyCompromise", "CACompromise",
365           "affiliationChanged", "superseded", "cessationOfOperation",
366           "certificateHold", "privilegeWithdrawn", and "AACompromise".
367
368       onlyuser, onlyCA, onlyAA, indirectCRL
369           The value for each of these names is a boolean.
370
371       Example:
372
373        [extensions]
374        issuingDistributionPoint = critical, @idp_section
375
376        [idp_section]
377        fullname = URI:http://example.com/myca.crl
378        indirectCRL = TRUE
379        onlysomereasons = keyCompromise, CACompromise
380
381   Certificate Policies
382       This is a raw extension that supports all of the defined fields of the
383       certificate extension.
384
385       Policies without qualifiers are specified by giving the OID.  Multiple
386       policies are comma-separated. For example:
387
388        certificatePolicies = 1.2.4.5, 1.1.3.4
389
390       To include policy qualifiers, use the "@section" syntax to point to a
391       section that specifies all the information.
392
393       The section referred to must include the policy OID using the name
394       policyIdentifier. cPSuri qualifiers can be included using the syntax:
395
396        CPS.nnn = value
397
398       where "nnn" is a number.
399
400       userNotice qualifiers can be set using the syntax:
401
402        userNotice.nnn = @notice
403
404       The value of the userNotice qualifier is specified in the relevant
405       section.  This section can include explicitText, organization, and
406       noticeNumbers options. explicitText and organization are text strings,
407       noticeNumbers is a comma separated list of numbers. The organization
408       and noticeNumbers options (if included) must BOTH be present. Some
409       software might require the ia5org option at the top level; this changes
410       the encoding from Displaytext to IA5String.
411
412       Example:
413
414        [extensions]
415        certificatePolicies = ia5org, 1.2.3.4, 1.5.6.7.8, @polsect
416
417        [polsect]
418        policyIdentifier = 1.3.5.8
419        CPS.1 = "http://my.host.example.com/"
420        CPS.2 = "http://my.your.example.com/"
421        userNotice.1 = @notice
422
423        [notice]
424        explicitText = "Explicit Text Here"
425        organization = "Organisation Name"
426        noticeNumbers = 1, 2, 3, 4
427
428       The character encoding of explicitText can be specified by prefixing
429       the value with UTF8, BMP, or VISIBLE followed by colon. For example:
430
431        [notice]
432        explicitText = "UTF8:Explicit Text Here"
433
434   Policy Constraints
435       This is a multi-valued extension which consisting of the names
436       requireExplicitPolicy or inhibitPolicyMapping and a non negative
437       integer value. At least one component must be present.
438
439       Example:
440
441        policyConstraints = requireExplicitPolicy:3
442
443   Inhibit Any Policy
444       This is a string extension whose value must be a non negative integer.
445
446       Example:
447
448        inhibitAnyPolicy = 2
449
450   Name Constraints
451       This is a multi-valued extension. The name should begin with the word
452       permitted or excluded followed by a ;. The rest of the name and the
453       value follows the syntax of subjectAltName except email:copy is not
454       supported and the IP form should consist of an IP addresses and subnet
455       mask separated by a /.
456
457       Examples:
458
459        nameConstraints = permitted;IP:192.168.0.0/255.255.0.0
460
461        nameConstraints = permitted;email:.example.com
462
463        nameConstraints = excluded;email:.com
464
465   OCSP No Check
466       This is a string extension. It is parsed, but ignored.
467
468       Example:
469
470        noCheck = ignored
471
472   TLS Feature (aka Must Staple)
473       This is a multi-valued extension consisting of a list of TLS extension
474       identifiers. Each identifier may be a number (0..65535) or a supported
475       name.  When a TLS client sends a listed extension, the TLS server is
476       expected to include that extension in its reply.
477
478       The supported names are: status_request and status_request_v2.
479
480       Example:
481
482        tlsfeature = status_request
483

DEPRECATED EXTENSIONS

485       The following extensions are non standard, Netscape specific and
486       largely obsolete. Their use in new applications is discouraged.
487
488   Netscape String extensions
489       Netscape Comment (nsComment) is a string extension containing a comment
490       which will be displayed when the certificate is viewed in some
491       browsers.  Other extensions of this type are: nsBaseUrl,
492       nsRevocationUrl, nsCaRevocationUrl, nsRenewalUrl, nsCaPolicyUrl and
493       nsSslServerName.
494
495   Netscape Certificate Type
496       This is a multi-valued extensions which consists of a list of flags to
497       be included. It was used to indicate the purposes for which a
498       certificate could be used. The basicConstraints, keyUsage and extended
499       key usage extensions are now used instead.
500
501       Acceptable values for nsCertType are: client, server, email, objsign,
502       reserved, sslCA, emailCA, objCA.
503

ARBITRARY EXTENSIONS

505       If an extension is not supported by the OpenSSL code then it must be
506       encoded using the arbitrary extension format. It is also possible to
507       use the arbitrary format for supported extensions. Extreme care should
508       be taken to ensure that the data is formatted correctly for the given
509       extension type.
510
511       There are two ways to encode arbitrary extensions.
512
513       The first way is to use the word ASN1 followed by the extension content
514       using the same syntax as ASN1_generate_nconf(3).  For example:
515
516        [extensions]
517        1.2.3.4 = critical, ASN1:UTF8String:Some random data
518        1.2.3.4.1 = ASN1:SEQUENCE:seq_sect
519
520        [seq_sect]
521        field1 = UTF8:field1
522        field2 = UTF8:field2
523
524       It is also possible to use the word DER to include the raw encoded data
525       in any extension.
526
527        1.2.3.4 = critical, DER:01:02:03:04
528        1.2.3.4.1 = DER:01020304
529
530       The value following DER is a hex dump of the DER encoding of the
531       extension Any extension can be placed in this form to override the
532       default behaviour.  For example:
533
534        basicConstraints = critical, DER:00:01:02:03
535

WARNINGS

537       There is no guarantee that a specific implementation will process a
538       given extension. It may therefore be sometimes possible to use
539       certificates for purposes prohibited by their extensions because a
540       specific application does not recognize or honour the values of the
541       relevant extensions.
542
543       The DER and ASN1 options should be used with caution. It is possible to
544       create invalid extensions if they are not used carefully.
545

SEE ALSO

547       openssl-req(1), openssl-ca(1), openssl-x509(1), ASN1_generate_nconf(3)
548
550       Copyright 2004-2021 The OpenSSL Project Authors. All Rights Reserved.
551
552       Licensed under the Apache License 2.0 (the "License").  You may not use
553       this file except in compliance with the License.  You can obtain a copy
554       in the file LICENSE in the source distribution or at
555       <https://www.openssl.org/source/license.html>.
556
557
558
5593.0.9                             2023-07-27              X509V3_CONFIG(5ossl)
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