When we encrypt data we are basically taking the plaintext information and applying some key material or keystream and conducting something called an XOR or Exclusive-OR operation.
The symbol used for XOR is the following: ⊕ This is a type of cipher known as a stream cipher.
The operation looks like this:
0101 0001 Plain text
0111 0011 Key stream
0010 0010 Output (ciphertext)
As you can see, it's not simple addition and the XOR Operation uses something called a truth table that explains why 0+1=1 and 1+1=0.
The rules are simples, if both bits are the same the result is zero, if both bits are not the same the result is one.
The following answers are incorrect:
- Bit Swapping: Incorrect. This isn't a known cryptographic operations.
- Logical NOR: Sorry, this isn't correct but is where only 0+0=1. All other combinations of 1+1, 1+0 equals 0. More on NOR here.
- Decryption: Sorry, this is the opposite of the process of encryption or, the process of applying the keystream to the plaintext to get the resulting encrypted text.
The following reference(s) was used to create this question:
For more details on XOR and all other QUESTION NO: s of cryptography. Subscribe to our holistic Security+ CBT tutorial at http://www.cccure.tv
and
http://en.wikipedia.org/wiki/Exclusive-or
and
http://en.wikipedia.org/wiki/Stream_cipher
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