Question 11501 – APPSC-2012-DL CA
March 27, 2024Question 11504 – APPSC-2012-DL CA
March 27, 2024Computer-Networks
| Question 378 |
Consider following three statements about Data Encryption Standard (DES).
(I) DES uses a 56 bit key to encrypt 64 bit data blocks.
(II) DES is a Block cipher.
(III) DES provides Cipher Block Chaining mode to overcome the problem of poor diffusion.
The false statement from above statements is/are
| Only (I) | |
| Only (I) and (III) | |
| Only (III)
| |
| None from (I), (II) and (III)
|
Question 378 Explanation:
DES is a block cipher, and encrypts data in blocks of size of 64 bit each, means 64 bits of plain text goes as the input to DES, which produces 64 bits of cipher text. The same algorithm and key are used for encryption and decryption, with minor differences. The key length is 56 bits. The basic idea is show in figure.To overcome the problem of poor diffusion, DES provides a cipher block chaining (CBC) mode.
Hence all the statements are true.
Hence all the statements are true.
Correct Answer: D
Question 378 Explanation:
DES is a block cipher, and encrypts data in blocks of size of 64 bit each, means 64 bits of plain text goes as the input to DES, which produces 64 bits of cipher text. The same algorithm and key are used for encryption and decryption, with minor differences. The key length is 56 bits. The basic idea is show in figure.To overcome the problem of poor diffusion, DES provides a cipher block chaining (CBC) mode.
Hence all the statements are true.
Hence all the statements are true.
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