Glossary

The 256-bit AES algorithm is based on a block cipher, which means it divides the data to be encrypted into blocks of 128 bits and encrypts each block separately. This increases the security of the algorithm as it becomes harder to detect patterns in the encrypted data and guess the key.

The 256-bit AES algorithm also employs a round function that applies a specific number of transformations to the data to encrypt it. The number of rounds depends on the key length. With a key length of 256 bits, 14 rounds are performed, with each round applying a combination of substitution and permutation operations to further obfuscate the data.

An important characteristic of the 256-bit AES algorithm is its key dependence. Each key results in a different encryption of the data. Therefore, it is very difficult for an attacker to guess the key through brute-force attacks, which involve trying every possible key.

The security of the 256-bit AES algorithm is also based on the non-linearity of the S-box used in the SubBytes transformation. The S-box is a table of 256 entries that maps every possible 8-bit input to a unique 8-bit output. The S-box ensures that each input bit of the encryption function undergoes a non-linear transformation, making the output harder to predict.

The 256-bit AES algorithm also provides high resistance against various attack techniques such as differential and linear cryptanalysis, as well as meet-in-the-middle attacks. These attacks exploit specific properties of the encryption function to guess the key. However, the 256-bit AES algorithm was designed to make these attacks difficult or even prevent them.

Overall, the 256-bit AES algorithm offers a very high level of security that is sufficient for most applications. However, there are some applications that require even higher security requirements, such as cryptography in government or military settings. In these cases, algorithms with even longer key lengths are often used.