Encryption system for digital data, uses secondary key to mask primary key, is more difficult to decrypt by Brute Force Attack than data encrypted with conventional single key

摘要

The unencrypted data (X) is fed to a cryptographic processor (P) where is encrypted by a primary key (K) to produce the encrypted output (Y). The processor is of the 'Data Encryption Standard type. In the present system, the primary key (K) is produced by another processor (P-asterisk) which is itself fed with a secondary key (K-asterisk) and an ancillary key (K').