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Transposition Ciphers. Reference Matt Bishop, Computer Security , Addison Wesley, 2003. Transposition Ciphers (p.2). A transposition cipher rearranges the plaintext to form the ciphertext. There is no substitution of characters. The key of the transposition cipher is a permutation function.
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Transposition Ciphers • Reference • Matt Bishop, Computer Security, Addison Wesley, 2003.
Transposition Ciphers (p.2) • A transposition cipher rearranges the plaintext to form the ciphertext. • There is no substitution of characters. • The key of the transposition cipher is a permutation function.
Transposition Ciphers (p.3) • A simple example is the “rail fence” cipher. • Let M be a sequence such as “HELLO, WORLD”. • Ignore spaces and punctuation, and rewrite the string into two rows: • HLOOL • ELWRD • The ciphertext C becomes “HLOOLELWRD”