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Theory

Pretest

Procedure

Simulation

Posttest

References

Feedback

Experiment 3 - DES Decryption

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Beginner

Intermediate

Advanced

In DES decryption, what happens after the 16 rounds of processing?

a: Initial permutation Explanation

Explanation

b: Final permutation Explanation

Explanation

c: Inverse initial permutation Explanation

Explanation

d: Subkeys are generated Explanation

Explanation

If a ciphertext block is decrypted with DES using the wrong key, what is the result?

a: The original plaintext with some errors Explanation

Explanation

b: An easily correctable piece of plaintext Explanation

Explanation

c: A completely different and random plaintext Explanation

Explanation

d: The ciphertext remains unchanged Explanation

Explanation

Which of the following steps is identical in both DES encryption and decryption?

a: Order of applying round keys Explanation

Explanation

b: Feistel round function Explanation

Explanation

c: Final permutation application Explanation

Explanation

d: Key generation process Explanation

Explanation

The Feistel function during DES decryption takes which inputs?

a: Left half and round key Explanation

Explanation

b: Right half and round key Explanation

Explanation

c: Entire 64-bit block and round key Explanation

Explanation

d: 48-bit key only Explanation

Explanation

DES decryption reverses the effect of encryption primarily by:

a: Using inverse S-boxes Explanation

Explanation

b: Reapplying the initial key Explanation

Explanation

c: Reversing the round key sequence Explanation

Explanation

d: Halving the block size Explanation

Explanation

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