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Instructions for Cryptography Feature for Data Security

IP.com Disclosure Number: IPCOM000087154D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Guyette, RR: AUTHOR

Abstract

The drawing shows the format of an instruction for enciphering and deciphering data in a data processing system. The op code section of the instruction may identify one of five instructions: Encipher Data, Decipher Data, Encipher Clear Keys, Generate External Key and Retrieve External Key.

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Instructions for Cryptography Feature for Data Security

The drawing shows the format of an instruction for enciphering and deciphering data in a data processing system. The op code section of the instruction may identify one of five instructions: Encipher Data, Decipher Data, Encipher Clear Keys, Generate External Key and Retrieve External Key.

In the instruction Encipher Data, storage address location B1, D1 holds the data to be enciphered and storage address location B2, D2 receives the enciphered data. The cryptography feature of the processor uses an operational key K0 for the enciphering operation. The operational key is known only to the user of the key and this key appears in storage only as an enciphered key EK0 that is enciphered by the cryptography feature under a master key KM. For an enciphering operation, the user loads the enciphered key EK0 into general purpose registers R0 and R1. The cryptography feature performs a decipher operation on key EK0 to produce the operational key K0, which is available only within the enciphering hardware.

A program interrupt occurs during the execution, of this instruction when the cryptography feature is not installed, when a fetch is not possible on operand 2 or a store operation is not possible on operand 1, and when the number of bytes to be enciphered is not divisible by 8. The user organizes the data so that it is enciphered in units of 8 bytes. The condition code is set to show whether the enciphering operation is successful and whether the operation was inhibited beca...