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EC-Council

312-50V11 · Question #502

XOR is a common cryptographic tool. 10110001 XOR 00111010 is?

The correct answer is D. 10001011. XOR (exclusive OR) produces a 1 only when the two input bits differ; applying it bit-by-bit to 10110001 and 00111010 yields 10001011.

Cryptography

Question

XOR is a common cryptographic tool. 10110001 XOR 00111010 is?

Options

  • A10111100
  • B11011000
  • C10011101
  • D10001011

How the community answered

(30 responses)
  • A
    3% (1)
  • B
    10% (3)
  • C
    3% (1)
  • D
    83% (25)

Why each option

XOR (exclusive OR) produces a 1 only when the two input bits differ; applying it bit-by-bit to 10110001 and 00111010 yields 10001011.

A10111100

10111100 (188 decimal) does not result from XORing 10110001 and 00111010; it reflects incorrect calculations in multiple bit positions.

B11011000

11011000 (216 decimal) is not the XOR result of the two operands; XOR cannot produce a value larger than the bitwise OR of the inputs without carry logic, which XOR does not use.

C10011101

10011101 (157 decimal) does not result from XORing 10110001 and 00111010; several bit positions have been computed incorrectly.

D10001011Correct

Performing XOR bit-by-bit on 10110001 and 00111010 gives: 1^0=1, 0^0=0, 1^1=0, 1^1=0, 0^1=1, 0^0=0, 0^1=1, 1^0=1, producing 10001011. XOR is fundamental to cryptography because it is perfectly reversible - XORing a ciphertext with the same key recovers the plaintext exactly - making it the core operation in stream ciphers and one-time pads.

Concept tested: Bitwise XOR operation applied to binary values

Source: https://csrc.nist.gov/glossary/term/exclusive_or

Topics

#XOR operation#bitwise arithmetic#symmetric encryption#cryptographic operations

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