The XOR (exclusive or) algorithm is a straightforward encryption method that relies on the XOR operation, a binary operation that produces an output based on the differences between corresponding bits of the text and some specified binary key. This algorithm is symmetric that means there is one key for both encryption and decryption.

What is XOR operation?

The XOR operation compares each pair of bits and returns 1 if the bits are different and 0 if they are the same. Represented by the symbol ⊕.
XOR offers symmetry and reversibility, making it suitable for encryption and decryption processes.

Here's the truth table for the XOR operation:

Algorithm implementation

1. Encryption Process: The encryption process involves XORing each bit of the plaintext with the corresponding bit of the key. If the bits are the same, the result is 0; if different, the result is 1. This process is iterated for each bit in the plaintext, producing the ciphertext;
2. Decryption Process: Decryption is a mirror image of encryption. XORing the ciphertext with the same key used for encryption restores the original plaintext. The XOR operation is symmetric; XORing twice with the same value yields the initial value;
3. Variable-Length Keys: In some XOR-based encryption implementations, the key's length may differ from that of the plaintext. To accommodate this, the key is repeated cyclically to match the plaintext's length. This repetition ensures a consistent XOR operation throughout the entire message, maintaining the algorithm's integrity.

Example

Let's create a simple example of XOR encryption using the XOR truth table. For simplicity, we'll use a binary message and a binary key.

Message: 1101.
Key: 1010.
Encryption:

Note

To encrypt text massages we have convert our text to binary format. We can do it using ASCII table: characters are initially encoded as numerical codes, and subsequently, these codes are converted into binary format.