Patent ID: 7770024

Claim:
A method for executing a message authentication code instruction in a computer system, the method comprising: determining from a previously defined function code selected from a plurality of function codes a message authentication code operation to-be-executed, the previously defined function code selected from the group consisting of a message authentication code generation operation and a function query operation to-be-executed, wherein the plurality of function codes selected from the group consisting of a KMAC-Query operation, a KMAC-DEA 64-bit key cryptographic operation, a KMAC-Triple DEA two 64-bit key cryptographic operation and a KMAC-Triple DEA three 64-bit key cryptographic operation; responsive to the determined message authentication code operation to-be-executed being a message authentication code generation operation, performing the message authentication code generation operation on an operand, the message authentication code generation operation comprising a) through b): a) computing a message authentication code for an operand using one or more cryptographic user keys and an 8 byte chaining value, the operand comprising one or more 8-byte message blocks, wherein the computing the message authentication code produces a new 8 byte chaining value; and b) storing the produced new 8 byte chaining value; responsive to the determined message authentication code operation to-be-executed being a function query operation, performing the function query operation, the function query operation comprising c) through d): c) determining for each of one or more message authentication functions whether the message authentication function is installed on the computer system for execution by a message authentication code instruction; and d) saving a status word in a parameter block in memory, the parameter block having an address specified by a first general register, the status word comprising one or more status word bits, each one of the one or more status word bits indicating whether a corresponding one of said one or more message authentication functions is installed on said computer system, each one of the one or more status word bits having a position in the status word corresponding to the function field value of the corresponding message authentication function.