Abstract: MUSE, a programmable multistream encryption system for secure communication provides dynamic cryptographic security and a highly efficient surveillance mechanism for transferring very large blocks of data (VLBD) subject to real-time constraints. Encryption varies pseudorandomly in both space and time. MUSE allows the user to specify a finite state machine which sequentially accepts parallel streams of data (VLBD) and encrypts this data in real time employing an arithmetic-algebraic pseudorandom array generator (PRAG). The method of enciphering is a one-time algebraic pad system which views the incoming data streams as elements from an algebraic alphabet (finite ring) and encrypts by adding to this a pseudorandom vector sequence iteratively generated from a single seed key. Decipherment is obtained by reversing this process.