Write down the encryption and decryption process at 2-DES and 3-DES. E | Cryptography 2080

Cryptography208010 marksNumerical: Polynomial division GF(7)Double DES

Write down the encryption and decryption process at 2-DES and 3-DES. Explain the Fiestal cipher structure. Divide $5x^2 + 4x + 6$ by $2x + 1$ over GF(7). [10]

--- 2-DES applies the DES algorithm twice with two independent keys $K1$ and $K2$ (each 56 bits, giving 112-bit effective key length). Encryption: $C = E{K2}(E{K1}(P))$ Plaintext $P$ is first encrypted with $K1$ to give an intermediate value, which is then encrypted with $K2$ to produce ciphert...

--- 2-DES applies the DES algorithm twice with two independent keys $K1$ and $K2$ (each 56 bits, giving 112-bit effective key length). Encryption: $$C = E{K2}(E{K1}(P))$$ Plaintext $P$ is first encrypted with $K1$ to give an intermediate value, which is then encrypted with $K2$ to produce ciphert...

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Write down the encryption and decryption process at 2-DES and 3-DES. Explain the Fiestal cipher structure. Divide 5x2 + 4x + 6 by 2x + 1 over GF(7).