DES uses keys of what size?

Data Encryption Standard (DES) utilizes a key size of 56 bits. This key length is significant in the context of cryptography because it directly influences the security level of the encryption. The 56-bit key allows for a total of 2^56 possible keys, which, while it was considered secure at the time of DES's introduction in the 1970s, has since become vulnerable to brute-force attacks due to advancements in computational power.

Understanding the importance of key size is crucial when discussing cryptographic algorithms. A longer key size generally provides a higher level of security, as it increases the number of possible key combinations an attacker must try in order to successfully decrypt the data. However, DES's relatively short key length has led to the development of more secure encryption methods, such as AES (Advanced Encryption Standard), which utilizes longer key lengths like 128, 192, or 256 bits for enhanced security.

In this case, the correct choice clearly reflects the specified key length associated with DES, underscoring the importance of recognizing the historical context of encryption standards and their evolving security requirements.