When we encrypt or decrypt data there is a basic operation involving ones and zeros where they are compared
in a process that looks something like this:
0101 0001 Plain text
0111 0011 Key stream
0010 0010 Output
What is this cryptographic operation called?

A.
Exclusive-OR

B.
Bit Swapping

C.
Logical-NOR

D.
Decryption

Explanation:
A plaintext message that needs to be encrypted is converted into bits, and the one-time pad is made up of
random bits. This encryption process makes use of a binary mathematic function called exclusive-OR (XOR).
Incorrect Answers:
B: Bit-swapping is the essential adaptive hand-shaking mechanism used by DMT modems to adapt to line
changes.
C: Logical-NOR is a truth-functional operator which produces a result that is the denial of Logical-Or.
D: Decryption is the process of translating encrypted data back into its original form.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, pp. 771
http://web.stanford.edu/group/cioffi/documents/bit_swapping.pdf
https://en.wikipedia.org/wiki/Logical_NOR
http://searchsecurity.techtarget.com/definition/data-encryption-decryption-IC