Updated: 2021/Apr/14


ASN1_generate_nconf(3)              OpenSSL             ASN1_generate_nconf(3)



NAME
       ASN1_generate_nconf, ASN1_generate_v3 - ASN1 generation functions

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/asn1.h>

        ASN1_TYPE *ASN1_generate_nconf(const char *str, CONF *nconf);
        ASN1_TYPE *ASN1_generate_v3(const char *str, X509V3_CTX *cnf);

DESCRIPTION
       These functions generate the ASN1 encoding of a string in an ASN1_TYPE
       structure.

       str contains the string to encode nconf or cnf contains the optional
       configuration information where additional strings will be read from.
       nconf will typically come from a config file whereas cnf is obtained
       from an X509V3_CTX structure which will typically be used by X509 v3
       certificate extension functions. cnf or nconf can be set to NULL if no
       additional configuration will be used.

GENERATION STRING FORMAT
       The actual data encoded is determined by the string str and the
       configuration information. The general format of the string is:

       [modifier,]type[:value]

       That is zero or more comma separated modifiers followed by a type
       followed by an optional colon and a value. The formats of type, value
       and modifier are explained below.

   Supported Types
       The supported types are listed below. Unless otherwise specified only
       the ASCII format is permissible.

       BOOLEAN, BOOL
           This encodes a boolean type. The value string is mandatory and
           should be TRUE or FALSE. Additionally TRUE, true, Y, y, YES, yes,
           FALSE, false, N, n, NO and no are acceptable.

       NULL
           Encode the NULL type, the value string must not be present.

       INTEGER, INT
           Encodes an ASN1 INTEGER type. The value string represents the value
           of the integer, it can be prefaced by a minus sign and is normally
           interpreted as a decimal value unless the prefix 0x is included.

       ENUMERATED, ENUM
           Encodes the ASN1 ENUMERATED type, it is otherwise identical to
           INTEGER.

       OBJECT, OID
           Encodes an ASN1 OBJECT IDENTIFIER, the value string can be a short
           name, a long name or numerical format.

       UTCTIME, UTC
           Encodes an ASN1 UTCTime structure, the value should be in the
           format YYMMDDHHMMSSZ.

       GENERALIZEDTIME, GENTIME
           Encodes an ASN1 GeneralizedTime structure, the value should be in
           the format YYYYMMDDHHMMSSZ.

       OCTETSTRING, OCT
           Encodes an ASN1 OCTET STRING. value represents the contents of this
           structure, the format strings ASCII and HEX can be used to specify
           the format of value.

       BITSTRING, BITSTR
           Encodes an ASN1 BIT STRING. value represents the contents of this
           structure, the format strings ASCII, HEX and BITLIST can be used to
           specify the format of value.

           If the format is anything other than BITLIST the number of unused
           bits is set to zero.

       UNIVERSALSTRING, UNIV, IA5, IA5STRING, UTF8, UTF8String, BMP,
       BMPSTRING, VISIBLESTRING, VISIBLE, PRINTABLESTRING, PRINTABLE, T61,
       T61STRING, TELETEXSTRING, GeneralString, NUMERICSTRING, NUMERIC
           These encode the corresponding string types. value represents the
           contents of this structure. The format can be ASCII or UTF8.

       SEQUENCE, SEQ, SET
           Formats the result as an ASN1 SEQUENCE or SET type. value should be
           a section name which will contain the contents. The field names in
           the section are ignored and the values are in the generated string
           format. If value is absent then an empty SEQUENCE will be encoded.

   Modifiers
       Modifiers affect the following structure, they can be used to add
       EXPLICIT or IMPLICIT tagging, add wrappers or to change the string
       format of the final type and value. The supported formats are
       documented below.

       EXPLICIT, EXP
           Add an explicit tag to the following structure. This string should
           be followed by a colon and the tag value to use as a decimal value.

           By following the number with U, A, P or C UNIVERSAL, APPLICATION,
           PRIVATE or CONTEXT SPECIFIC tagging can be used, the default is
           CONTEXT SPECIFIC.

       IMPLICIT, IMP
           This is the same as EXPLICIT except IMPLICIT tagging is used
           instead.

       OCTWRAP, SEQWRAP, SETWRAP, BITWRAP
           The following structure is surrounded by an OCTET STRING, a
           SEQUENCE, a SET or a BIT STRING respectively. For a BIT STRING the
           number of unused bits is set to zero.

       FORMAT
           This specifies the format of the ultimate value. It should be
           followed by a colon and one of the strings ASCII, UTF8, HEX or
           BITLIST.

           If no format specifier is included then ASCII is used. If UTF8 is
           specified then the value string must be a valid UTF8 string. For
           HEX the output must be a set of hex digits. BITLIST (which is only
           valid for a BIT STRING) is a comma separated list of the indices of
           the set bits, all other bits are zero.

RETURN VALUES
       ASN1_generate_nconf() and ASN1_generate_v3() return the encoded data as
       an ASN1_TYPE structure or NULL if an error occurred.

       The error codes that can be obtained by ERR_get_error(3).

EXAMPLES
       A simple IA5String:

        IA5STRING:Hello World

       An IA5String explicitly tagged:

        EXPLICIT:0,IA5STRING:Hello World

       An IA5String explicitly tagged using APPLICATION tagging:

        EXPLICIT:0A,IA5STRING:Hello World

       A BITSTRING with bits 1 and 5 set and all others zero:

        FORMAT:BITLIST,BITSTRING:1,5

       A more complex example using a config file to produce a SEQUENCE
       consisting of a BOOL an OID and a UTF8String:

        asn1 = SEQUENCE:seq_section

        [seq_section]

        field1 = BOOLEAN:TRUE
        field2 = OID:commonName
        field3 = UTF8:Third field

       This example produces an RSAPrivateKey structure, this is the key
       contained in the file client.pem in all OpenSSL distributions (note:
       the field names such as 'coeff' are ignored and are present just for
       clarity):

        asn1=SEQUENCE:private_key
        [private_key]
        version=INTEGER:0

        n=INTEGER:0xBB6FE79432CC6EA2D8F970675A5A87BFBE1AFF0BE63E879F2AFFB93644\
        D4D2C6D000430DEC66ABF47829E74B8C5108623A1C0EE8BE217B3AD8D36D5EB4FCA1D9

        e=INTEGER:0x010001

        d=INTEGER:0x6F05EAD2F27FFAEC84BEC360C4B928FD5F3A9865D0FCAAD291E2A52F4A\
        F810DC6373278C006A0ABBA27DC8C63BF97F7E666E27C5284D7D3B1FFFE16B7A87B51D

        p=INTEGER:0xF3929B9435608F8A22C208D86795271D54EBDFB09DDEF539AB083DA912\
        D4BD57

        q=INTEGER:0xC50016F89DFF2561347ED1186A46E150E28BF2D0F539A1594BBD7FE467\
        46EC4F

        exp1=INTEGER:0x9E7D4326C924AFC1DEA40B45650134966D6F9DFA3A7F9D698CD4ABEA\
        9C0A39B9

        exp2=INTEGER:0xBA84003BB95355AFB7C50DF140C60513D0BA51D637272E355E397779\
        E7B2458F

        coeff=INTEGER:0x30B9E4F2AFA5AC679F920FC83F1F2DF1BAF1779CF989447FABC2F5\
        628657053A

       This example is the corresponding public key in a SubjectPublicKeyInfo
       structure:

        # Start with a SEQUENCE
        asn1=SEQUENCE:pubkeyinfo

        # pubkeyinfo contains an algorithm identifier and the public key wrapped
        # in a BIT STRING
        [pubkeyinfo]
        algorithm=SEQUENCE:rsa_alg
        pubkey=BITWRAP,SEQUENCE:rsapubkey

        # algorithm ID for RSA is just an OID and a NULL
        [rsa_alg]
        algorithm=OID:rsaEncryption
        parameter=NULL

        # Actual public key: modulus and exponent
        [rsapubkey]
        n=INTEGER:0xBB6FE79432CC6EA2D8F970675A5A87BFBE1AFF0BE63E879F2AFFB93644\
        D4D2C6D000430DEC66ABF47829E74B8C5108623A1C0EE8BE217B3AD8D36D5EB4FCA1D9

        e=INTEGER:0x010001

SEE ALSO
       ERR_get_error(3)

COPYRIGHT
       Copyright 2002-2019 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



1.1.1i                            2019-06-09            ASN1_generate_nconf(3)