Information technology — ASN.1 encoding rules — Part 2: Specification of Packed Encoding Rules (PER)
The encoding rules specified in this document :
– are used at the time of communication;
– are intended for use in circumstances where minimizing the size of the representation of values is the major concern in the choice of encoding rules;
– allow the extension of an abstract syntax by addition of extra values, preserving the encodings of the existing values, for all forms of extension described in Rec. ITU-T X.680 | ISO/IEC 8824-1;
– can be modified in accordance with the provisions of Rec. ITU-T X.695 | ISO/IEC 8825-6.