The encryption service adapter (ESA) provides high-performance, hardware-based data encryption capabilities. This service adapter off-loads all CET encryption-related packet handling from host processors. The ESA uses the same Diffie-Hellman key exchange, Digital Signature Standard (DSS) and Data encryption Standard (DES) algorithms and procedures for complete compatibility with the Cisco Encryption Technology (CET) encryption services found in Cisco IOS Release 11.2 through 12.0. As a hardware-based solution, data encryption performance achieves up to 30 Mbps over serial and LAN ports with minimal impact on system resources.