OBJ_nid2obj(3) OpenSSL OBJ_nid2obj(3)NAME
OBJ_nid2obj, OBJ_nid2ln, OBJ_nid2sn, OBJ_obj2nid, OBJ_txt2nid,
OBJ_ln2nid, OBJ_sn2nid, OBJ_cmp, OBJ_dup, OBJ_txt2obj, OBJ_obj2txt,
OBJ_create, OBJ_cleanup - ASN1 object utility functions
ASN1_OBJECT * OBJ_nid2obj(int n);
const char * OBJ_nid2ln(int n);
const char * OBJ_nid2sn(int n);
int OBJ_obj2nid(const ASN1_OBJECT *o);
int OBJ_ln2nid(const char *ln);
int OBJ_sn2nid(const char *sn);
int OBJ_txt2nid(const char *s);
ASN1_OBJECT * OBJ_txt2obj(const char *s, int no_name);
int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name);
int OBJ_cmp(const ASN1_OBJECT *a,const ASN1_OBJECT *b);
ASN1_OBJECT * OBJ_dup(const ASN1_OBJECT *o);
int OBJ_create(const char *oid,const char *sn,const char *ln);
The ASN1 object utility functions process ASN1_OBJECT structures which
are a representation of the ASN1 OBJECT IDENTIFIER (OID) type.
OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID n to an
ASN1_OBJECT structure, its long name and its short name respectively,
or NULL is an error occurred.
OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the corresponding NID
for the object o, the long name <ln> or the short name <sn> respec‐
tively or NID_undef if an error occurred.
OBJ_txt2nid() returns NID corresponding to text string <s>. s can be a
long name, a short name or the numerical respresentation of an object.
OBJ_txt2obj() converts the text string s into an ASN1_OBJECT structure.
If no_name is 0 then long names and short names will be interpreted as
well as numerical forms. If no_name is 1 only the numerical form is
OBJ_obj2txt() converts the ASN1_OBJECT a into a textual representation.
The representation is written as a null terminated string to buf at
most buf_len bytes are written, truncating the result if necessary.
The total amount of space required is returned. If no_name is 0 then if
the object has a long or short name then that will be used, otherwise
the numerical form will be used. If no_name is 1 then the numerical
form will always be used.
OBJ_cmp() compares a to b. If the two are identical 0 is returned.
OBJ_dup() returns a copy of o.
OBJ_create() adds a new object to the internal table. oid is the numer‐
ical form of the object, sn the short name and ln the long name. A new
NID is returned for the created object.
OBJ_cleanup() cleans up OpenSSLs internal object table: this should be
called before an application exits if any new objects were added using
Objects in OpenSSL can have a short name, a long name and a numerical
identifier (NID) associated with them. A standard set of objects is
represented in an internal table. The appropriate values are defined in
the header file objects.h.
For example the OID for commonName has the following definitions:
#define SN_commonName "CN"
#define LN_commonName "commonName"
#define NID_commonName 13
New objects can be added by calling OBJ_create().
Table objects have certain advantages over other objects: for example
their NIDs can be used in a C language switch statement. They are also
static constant structures which are shared: that is there is only a
single constant structure for each table object.
Objects which are not in the table have the NID value NID_undef.
Objects do not need to be in the internal tables to be processed, the
functions OBJ_txt2obj() and OBJ_obj2txt() can process the numerical
form of an OID.
Create an object for commonName:
o = OBJ_nid2obj(NID_commonName);
Check if an object is commonName
if (OBJ_obj2nid(obj) == NID_commonName)
/* Do something */
Create a new NID and initialize an object from it:
new_nid = OBJ_create("188.8.131.52", "NewOID", "New Object Identifier");
obj = OBJ_nid2obj(new_nid);
Create a new object directly:
obj = OBJ_txt2obj("184.108.40.206", 1);
BUGSOBJ_obj2txt() is awkward and messy to use: it doesn't follow the con‐
vention of other OpenSSL functions where the buffer can be set to NULL
to determine the amount of data that should be written. Instead buf
must point to a valid buffer and buf_len should be set to a positive
value. A buffer length of 80 should be more than enough to handle any
OID encountered in practice.
RETURN VALUESOBJ_nid2obj() returns an ASN1_OBJECT structure or NULL is an error
OBJ_nid2ln() and OBJ_nid2sn() returns a valid string or NULL on error.
OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and OBJ_txt2nid() return a
NID or NID_undef on error.
0.9.7d 2003-11-20 OBJ_nid2obj(3)