Presentation Iss

1. Transposition
Chiper(Grid)

2. Transposition Ciphers
Transposition cipher – reorders (rearrange) symbols but does not disguise
them. It is also called permutation
With transposition, the cryptography aims for diffusion
◦ Widely spreading the information from the message or the key across the ciphertext
◦ Transpositions try to break established patterns
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3. Transposition Ciphers
1. Route Cipher 3

4. Transposition Ciphers
2. Rail Fence Cipher 4

5. Transposition Ciphers
3. Columnar Transposition
Plaintext written in rows
Number of columns = key length
Key is used to number the columns
Ciphertext reads out by columns, starting with column whose key letter is
lowest
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6. Transposition Ciphers
3. Columnar Transposition
For example:
◦ Assume we used ZEBRAS as keyword
◦ Plaintext (M): WE ARE DISCOVERED FLEE AT
ONCE
◦ Key (K): 6 3 2 4 1 5
◦ Ciphertext(C): EVLNE ACDTK ESEAQ ROFOJ DEECU
WIREE
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7. Example: Columnar cipher
Ciphertext(C): EVLNX ACDTX ESEAX ROFOX DEECX
WIREE
Key: 632415
Plaintext (M): WE ARE DISCOVERED FLEE AT ONCE