Visit Our UNIX and Linux User Community

Linux and UNIX Man Pages

Test Your Knowledge in Computers #729
Difficulty: Medium
BASIC stands for Basic All-purpose Symbolic Instruction Code.
True or False?
Linux & Unix Commands - Search Man Pages

asn1_generate_nconf(3ssl) [bsd man page]

ASN1_generate_nconf(3SSL)					      OpenSSL						 ASN1_generate_nconf(3SSL)

NAME
ASN1_generate_nconf, ASN1_generate_v3 - ASN1 generation functions SYNOPSIS
#include <openssl/asn1.h> ASN1_TYPE *ASN1_generate_nconf(char *str, CONF *nconf); ASN1_TYPE *ASN1_generate_v3(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 wherease 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 preceded 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. 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 consiting 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 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). SEE ALSO
ERR_get_error(3) HISTORY
ASN1_generate_nconf() and ASN1_generate_v3() were added to OpenSSL 0.9.8 1.0.1e 2014-08-06 ASN1_generate_nconf(3SSL)

Featured Tech Videos