6 OBJ_length, OBJ_get0_data, OBJ_nid2obj, OBJ_nid2ln,
7 OBJ_nid2sn, OBJ_obj2nid, OBJ_txt2nid, OBJ_ln2nid, OBJ_sn2nid, OBJ_cmp,
8 OBJ_dup, OBJ_txt2obj, OBJ_obj2txt, OBJ_create, OBJ_cleanup
9 - ASN1 object utility functions
13 #include <openssl/objects.h>
15 ASN1_OBJECT *OBJ_nid2obj(int n);
16 const char *OBJ_nid2ln(int n);
17 const char *OBJ_nid2sn(int n);
19 int OBJ_obj2nid(const ASN1_OBJECT *o);
20 int OBJ_ln2nid(const char *ln);
21 int OBJ_sn2nid(const char *sn);
23 int OBJ_txt2nid(const char *s);
25 ASN1_OBJECT *OBJ_txt2obj(const char *s, int no_name);
26 int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name);
28 int i2t_ASN1_OBJECT(char *buf, int buf_len, ASN1_OBJECT *a);
30 int OBJ_cmp(const ASN1_OBJECT *a, const ASN1_OBJECT *b);
31 ASN1_OBJECT *OBJ_dup(const ASN1_OBJECT *o);
33 int OBJ_create(const char *oid, const char *sn, const char *ln);
35 size_t OBJ_length(const ASN1_OBJECT *obj);
36 const unsigned char *OBJ_get0_data(const ASN1_OBJECT *obj);
40 #if OPENSSL_API_COMPAT < 0x10100000L
41 void OBJ_cleanup(void)
46 The ASN1 object utility functions process ASN1_OBJECT structures which are
47 a representation of the ASN1 OBJECT IDENTIFIER (OID) type.
49 OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID B<n> to
50 an ASN1_OBJECT structure, its long name and its short name respectively,
51 or B<NULL> is an error occurred.
53 OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the corresponding NID
54 for the object B<o>, the long name <ln> or the short name <sn> respectively
55 or NID_undef if an error occurred.
57 OBJ_txt2nid() returns NID corresponding to text string <s>. B<s> can be
58 a long name, a short name or the numerical representation of an object.
60 OBJ_txt2obj() converts the text string B<s> into an ASN1_OBJECT structure.
61 If B<no_name> is 0 then long names and short names will be interpreted
62 as well as numerical forms. If B<no_name> is 1 only the numerical form
65 OBJ_obj2txt() converts the B<ASN1_OBJECT> B<a> into a textual representation.
66 The representation is written as a null terminated string to B<buf>
67 at most B<buf_len> bytes are written, truncating the result if necessary.
68 The total amount of space required is returned. If B<no_name> is 0 then
69 if the object has a long or short name then that will be used, otherwise
70 the numerical form will be used. If B<no_name> is 1 then the numerical
71 form will always be used.
73 i2t_ASN1_OBJECT() is the same as OBJ_obj2txt() with the B<no_name> set to zero.
75 OBJ_cmp() compares B<a> to B<b>. If the two are identical 0 is returned.
77 OBJ_dup() returns a copy of B<o>.
79 OBJ_create() adds a new object to the internal table. B<oid> is the
80 numerical form of the object, B<sn> the short name and B<ln> the
81 long name. A new NID is returned for the created object.
83 OBJ_length() returns the size of the content octets of B<obj>.
85 OBJ_get0_data() returns a pointer to the content octets of B<obj>.
86 The returned pointer is an internal pointer which B<must not> be freed.
88 In OpenSSL versions prior to 1.1.0 OBJ_cleanup() cleaned up OpenSSLs internal
89 object table and was called before an application exits if any new objects were
90 added using OBJ_create(). This function is deprecated in version 1.1.0 and now
91 does nothing if called. No explicit de-initialisation is now required. See
92 L<OPENSSL_init_crypto(3)> for further information.
96 Objects in OpenSSL can have a short name, a long name and a numerical
97 identifier (NID) associated with them. A standard set of objects is
98 represented in an internal table. The appropriate values are defined
99 in the header file B<objects.h>.
101 For example the OID for commonName has the following definitions:
103 #define SN_commonName "CN"
104 #define LN_commonName "commonName"
105 #define NID_commonName 13
107 New objects can be added by calling OBJ_create().
109 Table objects have certain advantages over other objects: for example
110 their NIDs can be used in a C language switch statement. They are
111 also static constant structures which are shared: that is there
112 is only a single constant structure for each table object.
114 Objects which are not in the table have the NID value NID_undef.
116 Objects do not need to be in the internal tables to be processed,
117 the functions OBJ_txt2obj() and OBJ_obj2txt() can process the numerical
120 Some objects are used to represent algorithms which do not have a
121 corresponding ASN.1 OBJECT IDENTIFIER encoding (for example no OID currently
122 exists for a particular algorithm). As a result they B<cannot> be encoded or
123 decoded as part of ASN.1 structures. Applications can determine if there
124 is a corresponding OBJECT IDENTIFIER by checking OBJ_length() is not zero.
128 Create an object for B<commonName>:
131 o = OBJ_nid2obj(NID_commonName);
133 Check if an object is B<commonName>
135 if (OBJ_obj2nid(obj) == NID_commonName)
138 Create a new NID and initialize an object from it:
142 new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier");
144 obj = OBJ_nid2obj(new_nid);
146 Create a new object directly:
148 obj = OBJ_txt2obj("1.2.3.4", 1);
152 OBJ_obj2txt() is awkward and messy to use: it doesn't follow the
153 convention of other OpenSSL functions where the buffer can be set
154 to B<NULL> to determine the amount of data that should be written.
155 Instead B<buf> must point to a valid buffer and B<buf_len> should
156 be set to a positive value. A buffer length of 80 should be more
157 than enough to handle any OID encountered in practice.
161 OBJ_nid2obj() returns an B<ASN1_OBJECT> structure or B<NULL> is an
164 OBJ_nid2ln() and OBJ_nid2sn() returns a valid string or B<NULL>
167 OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and OBJ_txt2nid() return
168 a NID or B<NID_undef> on error.
176 OBJ_cleanup() was deprecated in OpenSSL 1.1.0.
180 Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
182 Licensed under the OpenSSL license (the "License"). You may not use
183 this file except in compliance with the License. You can obtain a copy
184 in the file LICENSE in the source distribution or at
185 L<https://www.openssl.org/source/license.html>.