XOR

XOR, or exclusive OR, is a logical bitwise operator that compares two binary inputs; it outputs true (or 1) only when the inputs are different. In the context of binary numbers, XOR compares each bit of two values and returns 1 if the bits are different and 0 if they are the same.

For two inputs, A and B, the XOR operation can be represented as follows:

• A XOR B = 1 if A ≠ B
• A XOR B = 0 if A = B

XOR is often used in encryption algorithms. One simple form is XOR cipher, where a key is applied to plaintext using the XOR operation. The same key is used to decrypt the ciphertext by XORing it again with the key.

• Example: plaintext XOR key = ciphertext, and then ciphertext XOR key = plaintext.
• This is effective when the key is random, used only once (one-time pad), and is as long as the plaintext.

In software, XOR is used to obfuscate code or data to hide its purpose or content from users or analysis tools. This can protect software from reverse engineering. XOR is a fundamental operation in many cryptographic hash functions, contributing to their ability to create a unique hash value from input data.

XOR is used in some algorithms for generating pseudo-random numbers, which are important in various cryptographic applications.