ASN1_GENERATE_NCONF(3) | Library Functions Manual | ASN1_GENERATE_NCONF(3) |
ASN1_generate_nconf
,
ASN1_generate_v3
— ASN.1
generation functions
#include
<openssl/asn1.h>
ASN1_TYPE *
ASN1_generate_nconf
(char *str,
CONF *nconf);
ASN1_TYPE *
ASN1_generate_v3
(char *str,
X509V3_CTX *cnf);
These functions generate the ASN.1 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.
BOOLEAN
,
BOOL
TRUE
or
FALSE
. Additionally true
,
Y
, y
,
YES
, yes
,
false
, N
,
n
, NO
and
no
are acceptable.NULL
INTEGER
,
INT
0x
is included.ENUMERATED
,
ENUM
INTEGER
.OBJECT
,
OID
UTCTIME
,
UTC
GENERALIZEDTIME
,
GENTIME
OCTETSTRING
,
OCT
ASCII
and HEX
can be used
to specify the format of value.BITSTRING
,
BITSTR
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.
BMPSTRING
,
BMP
, GeneralString
,
IA5STRING
, IA5
,
NUMERICSTRING
, NUMERIC
,
PRINTABLESTRING
, PRINTABLE
,
T61STRING
, T61
,
TELETEXSTRING
,
UNIVERSALSTRING
, UNIV
,
UTF8String
, UTF8
,
VISIBLESTRING
, VISIBLE
ASCII
or UTF8
.SEQUENCE
,
SEQ
, SET
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:
EXPLICIT
,
EXP
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
EXPLICIT
except IMPLICIT
tagging is used instead.OCTWRAP
,
SEQWRAP
, SETWRAP
,
BITWRAP
FORMAT
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 UTF-8 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 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 that 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 an ASN.1 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
ASN1_generate_nconf
() and
ASN1_generate_v3
() were added to OpenSSL 0.9.8.
December 25, 2016 | OpenBSD-6.1 |