DES

Data Encryption Standard

My thesis work involved the optimization of DES in assembler for the Intel Pentium processor. This resulted in speed records for both the Pentium and other PC processors, as shown in the table.

Processor	Key setup (enc&dec)	ECB		CBC
Processor	Key setup (enc&dec)	Encrypt	Decrypt	Encrypt	Decrypt
Pentium	576	315	315	316	318
Pentium 3	1124	319
Pentium 4	636	445
Athlon	496	240

Notes

This code was specifically optimized for the original Pentium. Only the encryption round function was then modified to improve performance on Pentium 3 and Athlon.