The IBM 7950, also known as Harvest, was a one-of-a-kind adjunct to the Stretch computer which was installed at the US National Security Agency (NSA). Built by IBM, it was delivered in 1962 and operated until 1976, when it was decommissioned. Harvest was designed to be used for cryptanalysis. From a single foreign cipher system, Harvest was able to scan over seven million decrypts for any occurrences of over 7,000 key words in under four hours.

The computer was also used for codebreaking, and this was enhanced by a system codenamed RYE, which allowed remote access to Harvest. According to a 1965 NSA report, “RYE has made it possible for the agency to locate many more potentially exploitable cryptographic systems and `bust’ situations. Many messages that would have taken hours or days to read by hand methods, if indeed the process were feasible at all, can now be `set’ and machine decrypted in a matter of minutes.” Harvest was also used for decipherment of solved systems; the report goes on to say that, “Decrypting a large batch of messages in a solved system [is] also being routinely handled by this system.”

Source: Wikipedia