Language and Codes
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Public Keys




Digital Signatures


Digital Cash


Syllabus for Language and Codes

Required Text: Cryptography Decrypted, by H.X. Mel, Doris Baker, and Steve Burnett

Weeks 1-3

Codes and Ciphers. Caesar's Cipher and other simple ciphers. Ciphers as permutations. Alan Turing and Enigma.

Weeks 4-6

Information and code-breaking. Statistical properties of language, codes, and ciphers. Claude Shannon and the one-time pad: a perfect code.

Weeks 7-9

Trust. The coin-flipping protocol. The concept of a digital signature: Authentication and nonrepudiation. Secure communication among strangers: Internet commerce. Exclusive or and distributed information. Zero-knowledge proofs. Digital Cash: Proving your identity without revealing who you are.

Week 10

Introduction to public key cryptography. One-way functions and modular arithmetic Diffie-Hellman. RSA.

Week 11

Treaty verification: Trust and the coin-flipping protocol revisited.

Week 12

Security and communication: Breaking codes by exploiting aspects of the communication situation.

Weeks 13-15

Codes and Information Theory. Shannon on codes. Codes and Compression. Codes and redundancy. ``Perfect'' codes revisited.