Here are a bunch of interesting links to various papers that helped us when developing and researching this project:

Cryptanalysis of Skipjack Reduced to 31 Rounds using Impossible Differentials
Author(s): Eli Biham, Alex Biryukov, Orr Dunkelman, Eran Richardson and Adi Shamir

Using the Fluhrer, Mantin, and Shamir Attack to Break WEP
Author(s): Adam Stubblefield, John Ioannidis and Aviel D. Rubin

Real Time Cryptanalysis of A5/1 on a PC
Author(s): Alex Biryukov, Adi Shamir and David Wagner

Cryptanalysis of the Cellular Message Encryption Algorithm
Author(s): David Wagner, Bruce Schneier and John Kelsey

Tiger: A Fast New Hash Function
Author(s): Ross Anderson and Eli Biham

Skype Security
Author(s): Simson L. Garfinkel

PGPfone 1.0 manual
Author(s): Philip R. Zimmermann