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Cryptography, for Fun and Profit. Synopsis. What is Cryptography? Some simple cryptographic systems and a modern application. An unbreakable cipher. Some modern algorithms (survey) Practical use of cryptography Some uses of cryptography. What is Cryptography?. Worst case conditions.
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Synopsis • What is Cryptography? • Some simple cryptographic systems and a modern application. • An unbreakable cipher. • Some modern algorithms (survey) • Practical use of cryptography • Some uses of cryptography.
Worst case conditions. • The cryptanalyst has complete knowledge of the cipher system • The cryptanalyst has a considerable amount of ciphertext • The cryptanalyst knows the plaintext equivalent of a certain amount of some ciphertext.
Some simple cryptographic systems and a modern application. • Caesar cipher. • A modern application: rot13. • Vigenere ciphers • Scrambling/transposition • Steganography • Main concept: modular arithmetic
An unbreakable cipher. • One-time-pad • Perfect secrecy
Some modern algorithms (survey) • Bit strings • Blocks • DES • AES • Diffie-Hellman • RSA
Practical use of cryptography • Be realistic
Some uses of Cryptography • Confidentiality • Integrity • Entity authentication • Source authentication • Non-repudiation • Certification Authorities • Data safeguarding and hijacking.