XOR ciphers use bitwise XOR operation for encryption and decryption.
How XOR works
- 0 XOR 0 = 0, 1 XOR 1 = 0.
- 0 XOR 1 = 1, 1 XOR 0 = 1.
- XOR with same key reverses operation: (A XOR B) XOR B = A.
Encryption process
- Convert plaintext and key to binary.
- XOR each bit of plaintext with corresponding key bit.
- Result is ciphertext.
- XOR ciphertext with same key to decrypt.
Security considerations
- Key must be random and never reused.
- One-time pad (OTP) with random key = unbreakable.
- Key reuse reveals patterns and enables attacks.
- Used in stream ciphers and network protocols.
Practical uses
- Teaching encryption concepts.
- Simple obfuscation (not security).
- Building block in modern encryption.
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