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Cryptography and Cryptanalysis. Reference Matt Bishop, Computer Security , Addison Wesley, 2003. Cryptography and Cryptanalysis (p.2). Cryptography The art and science of concealing meaning. The basic component of cryptography is a cryptosystem . Cryptanalysis The breaking of codes.
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Cryptography and Cryptanalysis • Reference • Matt Bishop, Computer Security, Addison Wesley, 2003.
Cryptography and Cryptanalysis (p.2) • Cryptography • The art and science of concealing meaning. • The basic component of cryptography is a cryptosystem. • Cryptanalysis • The breaking of codes.
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.
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.