US Patent 7242770 Secure encryption/decryption for elevators

This system relates to a secure encryption/decryption protocol for elevator displays and controls. The protocol uses an algorithm to scramble information before transmission and reassemble it after transmission. The system uses at least one block of data assembled into unencrypted N-bits of information. An encryption device encodes the data into at least one block of encrypted M-bits of information. A data encryption mask provides an encryption routine which also includes scrambling the data.