1. Cryptography and Cryptanalysis
Reference
Matt Bishop, Computer Security, Addison Wesley, 2003.

2. Cryptography and Cryptanalysis (p.2)
The art and science of concealing meaning.
The basic component of cryptography is a cryptosystem.
Cryptanalysis
The breaking of codes.

3. Cryptography and Cryptanalysis (p.3)
Cryptosystem--A five tuple {E,D,M,K,C}.
E -- set of Enciphering functions.
D -- set of Deciphering functions.
K-- set of Keys.
M--set of Messages, or plaintext.
C--set of Ciphertext.
The enciphering function and key operate on the plaintext to produce the ciphertext.
The deciphering function and key operate on the ciphertext to produce the plaintext.

4. Cryptography and Cryptanalysis (p.4)
Cryptanalysis Attacks--Assuming E and D are known.
Ciphertext Only--Knowing C, find M and possibly K.
Known Plaintext and Ciphertext--Find K.
Chosen Plaintext and Ciphertext--Find K.
A good cryptosystem protects against these.