Applying Quantum Search to a Known-Plaintext Attack on Two-Key Triple Encryption

The process of disguising a plaintext into ciphertext is called encryption and back into plaintext is called decryption. A cryptographic algorithm, is also called a cipher, is the mathematical function used for encryption and decryption. Many algorithms are available for this purpose. Triple DES is such an algorithm. Encryption using triple DES is possible in two different ways; they are triple DES with two keys and triple DES with three different keys. Cryptanalysis can be used to recover the plaintext of a message from the ciphertext without access to or knowing the key. Exhaustive key search remains the most practical and efficient attack on Triple DES with two keys. The principles of quantum mechanics can be used to build and analyze a quantum computer and its algorithms. Quantum searching is one such algorithm. The key search in Triple DES with two keys is possible using quantum search algorithm, which is more efficient compare to any other methods. In this paper we are presenting how quantum search can be used to crack Triple DES with two keys searching for a key.