What does the term 'Key Stretching' refer to in cryptography?

The term 'Key Stretching' in cryptography refers to enhancing encryption strength through additional processing. This process involves taking a weak key and applying a computationally intensive process to transform it into a stronger key. The idea is to make it significantly harder for attackers to use brute force methods to guess the key.

Key stretching typically involves algorithms that repeatedly hash the password or use other methods to perform numerous iterations of a function. This increases the time required for an attacker to test each possible key, effectively providing more security for systems that may rely on weaker passwords.

In contrast, the other choices do not accurately capture the essence of key stretching. Making encryption keys longer or creating shorter keys for faster processing does not convey the idea of enhancing strength through additional processing. Additionally, reducing memory requirements for key storage does not relate to key strengthening, as key stretching is focused on security rather than on resource efficiency. Therefore, the concept of enhancing encryption strength through additional processing is central to understanding key stretching in cryptography.