Overview:

So far, we have studied three transposition ciphers: Scytale Cipher, Block Rotate Cipher and Columnar Transposition. In this document, we will outline three other ciphers: Rail-fence Cipher, Permutation Cipher and Myszkowski Cipher.

Rail-fence Cipher

Encryption:

write the plaintext as a two-row zigzag, ,then read horizontally.

Example: POETRY IS LOST IN TRANSLATION

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Ciphertext: PERILSITASAINOTYSOTNRNLTO

Decryption:

Find the middle character, then insert the ciphertext horizontally and read in a zig-zag fashion.

Example: MKHSELWYAEATSOL

The character Y is the middle character. Then we split at that character

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plaintext: MAKE HASTE SLOWLY

A variation:

Instead of using a fixed number of rows = 2, let the key be the number of rows.

Example: key = 4

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Ciphertext: PIISN OYSTNNLO ERLSTAAI TORT

Cryptanalysis: