Which of the following is NOT considered a Cryptographic Principle?

Data compression is not considered a cryptographic principle because it does not directly involve the processes of encryption or decryption aimed at securing data. Cryptographic principles are foundational concepts that underpin the security and effectiveness of cryptographic algorithms and protocols.

Key length, key stretching, and initialization vectors are all critical components in cryptography. Key length refers to the size of the cryptographic key, which directly affects the security level—the longer the key, the more resistant it is to brute force attacks. Key stretching techniques are employed to make weak keys stronger by increasing the computational work required to brute-force the key. An initialization vector (IV) is used in encryption to ensure that the same plaintext encrypted multiple times results in different ciphertexts, thus enhancing security and preventing pattern recognition.

In contrast, while data compression can be useful for reducing the size of data for transmission or storage, it does not contribute to the security mechanisms of encryption or the safeguarding of data, thus making it distinct from the principle-based nature of cryptography.