1. Cullen, D.: Product Keys and Hashing (2010). https://bnetdocs.org/?op=doc&did=20
2. Lecture Notes in Computer Science;G Koning Gans de,2011
3. Licenturion: Inside Windows Product Activation, Germany (2001). http://www.licenturion.com/xp/
4. Luby, M., Rackoff, C.: How to construct pseudorandom permutations from pseudorandom functions. SIAM J. Comput. 17(2), 373–386 (1988)
5. Penton: Symmetric vs. Asymmetric Ciphers (2016). http://windowsitpro.com/security/symmetric-vs-asymmetric-ciphers