on 27 April 2001
PGP is an excellent piece of software. When this book was published, I am sure that it was an excellent book. Unfortunately it is now so out of date that it does not justify its cost.
The early chapters on cryptography, the history of public key systems, and the development of PGP are very good, worth reading and account for the 2 stars I have given this book. However, some of the information is now out of date, and anyone interested in a more up-to-date history of public key cryptography would be better served by buying Steven Levy's "Crypto".
The second part of this book deals with the use of PGP, and since the version described in the book is FIVE versions out of date, nearly all of this information is useless.
This could be an excellent book for anyone interested in public key cryptography who wants to get the most out of PGP. However, until Mr. Garfinkel updates it to cover the latest version, it will remain an expensive introduction to a fascinating subject and an incredible piece of software.
on 22 June 2013
This book is now old, and the section dealing with PGP is out of date.
However, it is of great historical interest in the field of cryptography. At the time of publication, Phil Zimmerman (the author of PGP software) was being hounded by the FBI for exporting "munitions", as cryptographic software of that capability was classified at that time, and it was illegal under US law to make such software available outside the USA. The case was eventually dropped. Zimmerman resisted at great personal cost as he felt privacy was a fundamental human right. He is a great hero in the cause of free speech. Just look at PRISM and the abuse of our privacy today!
It has an excellent section on general cryptography, although as the WWW has developed, much of these data are covered elsewhere, and for free.
Interestingly, the British services had invented the algorithms that PGP uses long before, but in the interests of secrecy had kept quiet about it!
Well worth reading.