ABSTRACT
The tape machine depicted in Section 3.9 can be seen as the beginning of a still ongoing area of cryptographic research-stream ciphers. Such systems attempt to generate random numbers that can be combined with the message in an approximation of the unbreakable one-time pad. The problem is that machines cannot generate random numbers. Thus, we usually refer to such numerical sequences as pseudorandom and the devices that create them as pseudorandom number generators, or PRNGs for short.
