Crypto by Steven Levy is a book aimed at readers, who want to get an overview of the origin of public key cryptography. Back in the Seventies, researchers such as Whitfield Diffie and Martin Hellman solved some fundamental problems of cryptography, such as key exchange. Later on, public key cryptography was invented.
The book begins at the time when Whitfield Diffie made a break-through in cryptography by inventing a new method of sharing symmetric keys between two parties – the Diffie-Hellman key exchange protocol. The book also describes the problems that existed related to the government. The NSA aimed to keep all of the crypto-knowledge private. They didn’t want others to work on such things or rather make crypto-stuff public. Therefore they established strict export regulations for cryptography. Only low-strength ciphers were allowed to be exported. breaking these rules was sanctioned with prison. But the NSA also had a vast interest in surveilling their citizen. A proof of this was the introduction of the Clipper-chip, loaded with a cipher created by the NSA in phones. This was in fact a government back door. It was a tough time for scientists, but thanks to people like Phil Zimmerman and its software “PGP” and others, cryptography, and especially public key cryptography, was made available to the masses. Therefore, the government was later on forced to revoke its export regulations.
To sum up, the book is definitely a good read if you are interested in the history of public key cryptography. Read it, if you want to understand the problems scientists and researchers had to cope with during that time. It also gives you a pretty good insight into how the government handles certain things. The book describes dialogs between persons in a very detailed and interesting way.