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           Several of the OpenSSL utilities can add extensions to a certificate or
           certificate request based on the contents of a configuration file.
           Typically the application will contain an option to point to an
           extension section. Each line of the extension section takes the form:
            extension_name=[critical,] extension_options
           If critical is present then the extension will be critical.
           The format of extension_options depends on the value of extension_name.
           There are four main types of extension: string extensions, multi-valued
           extensions, raw and arbitrary extensions.
           String extensions simply have a string which contains either the value
           itself or how it is obtained.
           For example:
            nsComment="This is a Comment"
           Multi-valued extensions have a short form and a long form. The short
           form is a list of names and values:
           The long form allows the values to be placed in a separate section:
           Both forms are equivalent.
           The syntax of raw extensions is governed by the extension code: it can
           for example contain data in multiple sections. The correct syntax to
           use is defined by the extension code itself: check out the certificate
           policies extension for an example.
           If an extension type is unsupported then the arbitrary extension syntax
           must be used, see the ARBITRARY EXTENSIONS section for more details.


           The following sections describe each supported extension in detail.
       Basic Constraints.
           This is a multi valued extension which indicates whether a certificate
           or exclude the extension entirely. Some software may require the
           inclusion of basicConstraints with CA set to FALSE for end entity
           The pathlen parameter indicates the maximum number of CAs that can
           appear below this one in a chain. So if you have a CA with a pathlen of
           zero it can only be used to sign end user certificates and not further
       Key Usage.
           Key usage is a multi valued extension consisting of a list of names of
           the permitted key usages.
           The supporte names are: digitalSignature, nonRepudiation,
           keyEncipherment, dataEncipherment, keyAgreement, keyCertSign, cRLSign,
           encipherOnly and decipherOnly.
            keyUsage=digitalSignature, nonRepudiation
            keyUsage=critical, keyCertSign
       Extended Key Usage.
           This extensions consists of a list of usages indicating purposes for
           which the certificate public key can be used for,
           These can either be object short names of the dotted numerical form of
           OIDs.  While any OID can be used only certain values make sense. In
           particular the following PKIX, NS and MS values are meaningful:
            Value                  Meaning
            -----                  -------
            serverAuth             SSL/TLS Web Server Authentication.
            clientAuth             SSL/TLS Web Client Authentication.
            codeSigning            Code signing.
            emailProtection        E-mail Protection (S/MIME).
            timeStamping           Trusted Timestamping
            msCodeInd              Microsoft Individual Code Signing (authenticode)
            msCodeCom              Microsoft Commercial Code Signing (authenticode)
            msCTLSign              Microsoft Trust List Signing
            msSGC                  Microsoft Server Gated Crypto
            msEFS                  Microsoft Encrypted File System
            nsSGC                  Netscape Server Gated Crypto
       Subject Key Identifier.
           This is really a string extension and can take two possible values.
           present then an error is returned if the option fails.
           The issuer option copies the issuer and serial number from the issuer
           certificate. This will only be done if the keyid option fails or is not
           included unless the "always" flag will always include the value.
       Subject Alternative Name.
           The subject alternative name extension allows various literal values to
           be included in the configuration file. These include email (an email
           address) URI a uniform resource indicator, DNS (a DNS domain name), RID
           (a registered ID: OBJECT IDENTIFIER), IP (an IP address), dirName (a
           distinguished name) and otherName.
           The email option include a special 'copy' value. This will
           automatically include and email addresses contained in the certificate
           subject name in the extension.
           The IP address used in the IP options can be in either IPv4 or IPv6
           The value of dirName should point to a section containing the
           distinguished name to use as a set of name value pairs. Multi values
           AVAs can be formed by preceeding the name with a + character.
           otherName can include arbitrary data associated with an OID: the value
           should be the OID followed by a semicolon and the content in standard
           ASN1_generate_nconf(3) format.
            subjectAltName=otherName:;UTF8:some other identifier
            O=My Organization
            OU=My Unit
            CN=My Name
       Issuer Alternative Name.
           The issuer alternative name option supports all the literal options of
           subject alternative name. It does not support the email:copy option
           because that would not make sense. It does support an additional
            authorityInfoAccess = OCSP;URI:
            authorityInfoAccess = caIssuers;URI:
       CRL distribution points.
           This is a multi-valued extension whose options can be either in
           name:value pair using the same form as subject alternative name or a
           single value representing a section name containing all the
           distribution point fields.
           For a name:value pair a new DistributionPoint with the fullName field
           set to the given value both the cRLissuer and reasons fields are
           omitted in this case.
           In the single option case the section indicated contains values for
           each field. In this section:
           If the name is "fullname" the value field should contain the full name
           of the distribution point in the same format as subject alternative
           If the name is "relativename" then the value field should contain a
           section name whose contents represent a DN fragment to be placed in
           this field.
           The name "CRLIssuer" if present should contain a value for this field
           in subject alternative name format.
           If the name is "reasons" the value field should consist of a comma
           separated field containing the reasons. Valid reasons are:
           "keyCompromise", "CACompromise", "affiliationChanged", "superseded",
           "cessationOfOperation", "certificateHold", "privilegeWithdrawn" and
           Simple examples:
           Full distribution point example:
            reasons=keyCompromise, CACompromise
           The names "onlyuser", "onlyCA", "onlyAA" and "indirectCRL" are also
           accepted the values should be a boolean value (TRUE or FALSE) to
           indicate the value of the corresponding field.
            issuingDistributionPoint=critical, @idp_section
            onlysomereasons=keyCompromise, CACompromise
            CN=Some Name
       Certificate Policies.
           This is a raw extension. All the fields of this extension can be set by
           using the appropriate syntax.
           If you follow the PKIX recommendations and just using one OID then you
           just include the value of that OID. Multiple OIDs can be set separated
           by commas, for example:
           If you wish to include qualifiers then the policy OID and qualifiers
           need to be specified in a separate section: this is done by using the
           @section syntax instead of a literal OID value.
           The section referred to must include the policy OID using the name
           policyIdentifier, cPSuri qualifiers can be included using the syntax:
           userNotice qualifiers can be set using the syntax:
           The value of the userNotice qualifier is specified in the relevant
           section.  This section can include explicitText, organization and
           noticeNumbers options. explicitText and organization are text strings,
           noticeNumbers is a comma separated list of numbers. The organization
           and noticeNumbers options (if included) must BOTH be present. If you
           use the userNotice option with IE5 then you need the 'ia5org' option at
           the top level to modify the encoding: otherwise it will not be
           interpreted properly.
           The ia5org option changes the type of the organization field. In
           RFC2459 it can only be of type DisplayText. In RFC3280 IA5Strring is
           also permissible.  Some software (for example some versions of MSIE)
           may require ia5org.
       Policy Constraints
           This is a multi-valued extension which consisting of the names
           requireExplicitPolicy or inhibitPolicyMapping and a non negative intger
           value. At least one component must be present.
            policyConstraints = requireExplicitPolicy:3
       Inhibit Any Policy
           This is a string extension whose value must be a non negative integer.
            inhibitAnyPolicy = 2
       Name Constraints
           The name constraints extension is a multi-valued extension. The name
           should begin with the word permitted or excluded followed by a ;. The
           rest of the name and the value follows the syntax of subjectAltName
           except email:copy is not supported and the IP form should consist of an
           IP addresses and subnet mask separated by a /.
           issuingDistributionPoint = idp_section
       OCSP No Check
           The OCSP No Check extension is a string extension but its value is
            noCheck = ignored


           The following extensions are non standard, Netscape specific and
           largely obsolete. Their use in new applications is discouraged.
       Netscape String extensions.
           be included. It was used to indicate the purposes for which a
           certificate could be used. The basicConstraints, keyUsage and extended
           key usage extensions are now used instead.
           Acceptable values for nsCertType are: client, server, email, objsign,
           reserved, sslCA, emailCA, objCA.


           If an extension is not supported by the OpenSSL code then it must be
           encoded using the arbitrary extension format. It is also possible to
           use the arbitrary format for supported extensions. Extreme care should
           be taken to ensure that the data is formatted correctly for the given
           extension type.
           There are two ways to encode arbitrary extensions.
           The first way is to use the word ASN1 followed by the extension content
           using the same syntax as ASN1_generate_nconf(3).  For example:
  ,ASN1:UTF8String:Some random data
            field1 = UTF8:field1
            field2 = UTF8:field2
           It is also possible to use the word DER to include the raw encoded data
           in any extension.
           The value following DER is a hex dump of the DER encoding of the
           extension Any extension can be placed in this form to override the
           default behaviour.  For example:


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


           If an extension is multi-value and a field value must contain a comma
           Due to the behaviour of the OpenSSL conf library the same field name
           can only occur once in a section. This means that:
           will only recognize the last value. This can be worked around by using
           the form:


           The X509v3 extension code was first added to OpenSSL 0.9.2.
           Policy mappings, inhibit any policy and name constraints support was
           added in OpenSSL 0.9.8
           The directoryName and otherName option as well as the ASN1 option for
           arbitrary extensions was added in OpenSSL 0.9.8


           req(1), ca(1), x509(1), ASN1_generate_nconf(3)

    1.0.1e 2013-02-11 X509V3_CONFIG(5)


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