BS 7112:1991

Committees responsible
National foreword
Method
0. Introduction
1. Scope and field of application
2. References
3. Definitions
4. Applicable interfaces
5. General requirements
6. Synchronous encipherment operation
7. Asynchronous encipherment operation
8. Bypass control facility (Optional)
Annexes
A. Background Information on Encipherment in the
    Physical Layer
B. Requirements for IV Structure and Transmission for
    DEAP
Tables
1. IV Derivation
2. IV Option 1
3. IV Option 2
Figures
1. Operation of the V.24 Interchange circuits showing
    data encipherment in one direction only
2. V.24 Half Duplex Transmission Signalling Sequence
    for Synchronous Encipherment, Alternative A
3. V.24 Half Duplex Transmission Signalling Sequence
    for Synchronous Encipherment, Alternative B
4. Start of asynchronous encipherment and a Class A
    BREAK operation
5. Class B BREAK operation
6. Bypass of encipherment for Test Loop Operation
7. SV Derivation from 49-bit IV, 7-bit Characters,
    Preferred Alternative
8. SV Derivation from 63-bit IV, 7-bit Characters,
    Acceptable Alternative 1
9. SV Derivation from 70-bit IV, 7-bit Characters,
    Acceptable Alternative 2

Applies to systems for encipherment of ADP information in the physical layer of data communications. Applicable whether the Data Encipherment Equipment is implemented as a physically separate piece of equipment or implemented as part of the Data Terminal Equipment or as part of the Data Circuit terminating Equipment. Applies to those portions of the DTE or DCE design which implement the requirements of this Standard. The physical layer is described in the Open Systems Interconnection Reference Model, ISO 7498. The main body specifies requirements applicable to the use of various encipherment algorithms. Specifies two alternative modes of synchronous operation. Gives two alternative actions for BREAK signalling for asynchronous operation.