An instance of class OM_C_ENCODING is an object represented in a form suitable for transmission between workspaces, for transport via a network, or for storage in a file. Encoding can also be a suitable way of indicating to an intermediate service provider (for example, a directory, or message transfer system) an object that it does not recognize.
This class has the attributes of its superclass, OM_C_OBJECT, in addition to the specific attributes listed in the following table.
Attributes Specific to OM_C_ENCODING
| Attribute |
Value Syntax | Value Length | Value Number | Value Initially |
| OM_OBJECT_ CLASS |
String(OM_S_ OBJECT_ IDENTIFIER_ STRING) |
- | 1 | - |
| OM_OBJECT_ ENCODING |
String See Note 18 |
- | 1 | - |
| OM_RULES | String(OM_S_ OBJECT_ IDENTIFIER_ STRING) |
- | 1 | ber |
This attribute identifies the class of the object that the Object Encoding attribute encodes. The class must be concrete.
· OM_OBJECT_ENCODING
This attribute is the encoding itself.
· OM_RULES
This attribute identifies the set of rules that are followed to produce the Object Encoding attribute. Among the defined values of this attribute are those represented as follows:
OM_BER
This value is specified in ASN.1 as
{joint-iso-ccitt(2) asn1(1) basic-encoding(1)}
This value indicates the BER. (See Clause 25.2 of Recommendation X.209, ''Specification of Basic Encoding Rules for Abstract Syntax Notation 1 (ASN.1),'' CCITT Blue Book, Fascicle VIII.4, International Telecommunications Union, 1988. Also published by ISO as ISO 8825.)
- OM_CANONICAL_BER
This value is specified in ASN.1 as
{joint-iso-ccitt(2) mhs-motis(6) group(6) white(1) api(2) om(4)
canonical-ber(4)}
This value indicates the canonical BER. (See Clause 8.7 of Recommendation X.509, ''The Directory: Authentication Framework,'' CCITT Blue Book, International Telecommunications Union, 1988. Also published by ISO as ISO 9594-8.)
Note: In general, an instance of this class cannot appear as a value whose syntax is Object (C) if C is not OM_C_ENCODING, even if the class of the object encoded is C.