What does the use of Exclusive OR (XOR) in symmetric encryption achieve?

The use of Exclusive OR (XOR) in symmetric encryption achieves confusion in cipher algorithms, which is a fundamental principle of cryptography aimed at obscuring the relationship between the plaintext and the ciphertext. When XOR is applied, it combines the plaintext with a key, producing ciphertext in such a way that any change in the plaintext or the key will lead to a significantly different ciphertext. This characteristic ensures that, without knowing the key, it is difficult for an attacker to derive any meaningful information about the original plaintext.

In addition, the XOR operation is reversible. If you XOR the ciphertext with the same key again, you recover the original plaintext. This property makes XOR particularly useful in symmetric encryption schemes where the same key is used for both encryption and decryption.

While other options are related to various cryptographic processes, they do not accurately describe the role of XOR in symmetric encryption. For example, adding random values does not encompass the essence of how XOR functions — it is more about direct interaction with bits. Comparing values for integrity pertains more to hashing or checksums, instead of the encryption process itself. Lastly, stating that XOR is used exclusively for hashing misrepresents its versatile application, particularly in encryption algorithms.