ASN1_GENERATE_NCONF(3SSL) | OpenSSL | ASN1_GENERATE_NCONF(3SSL) |
ASN1_generate_nconf, ASN1_generate_v3 - ASN1 generation functions
#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);
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.
The actual data encoded is determined by the string str and the configuration information. The general format of the string is:
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.
The supported types are listed below. Unless otherwise specified only the ASCII format is permissible.
If the format is anything other than BITLIST the number of unused bits is set to zero.
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.
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.
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.
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).
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
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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>.
2023-09-13 | 1.1.1w |