What is the Advanced Encryption Standard (AES) algorithm
Advanced Encryption Standard (AES) is a widely-used symmetric key encryption algorithm that is considered to be one of the most secure encryption standards in the world. It is designed to be highly secure, fast, and flexible, and is used in a wide range of applications, including online banking, e-commerce, and government communication. In this article, we will take a closer look at how AES works, its strengths and weaknesses, and its applications.
Let’s understand this algorithm in more detailed
How AES Works
AES is a symmetric key encryption algorithm, which means that the same key is used for both encryption and decryption. The key size can be either 128, 192, or 256 bits, and the plaintext is divided into 128-bit blocks. AES uses a series of substitution and permutation operations to transform the plaintext into ciphertext.
The AES algorithm consists of four main operations: SubBytes, ShiftRows, MixColumns, and AddRoundKey. These operations are repeated for a certain number of rounds, depending on the key size. For example, AES-128 uses 10 rounds, AES-192 uses 12 rounds, and AES-256 uses 14 rounds.
- SubBytes: In this operation, each byte of the plaintext is replaced with a corresponding byte from a pre-defined lookup table called the S-box. The S-box is created using a complex mathematical formula and is designed to be highly resistant to cryptographic attacks.
- ShiftRows: In this operation, the bytes of each row in the state matrix are shifted by a certain number of bytes. The first row is not shifted, the second row is shifted by one byte, the third row is shifted by two bytes, and the fourth row is shifted by three bytes.
- MixColumns: In this operation, each column of the state matrix is transformed using a mathematical formula that involves multiplication and addition. This operation is designed to provide diffusion and confusion, which are two key properties of secure encryption algorithms.
- AddRoundKey: In this operation, each byte of the state matrix is XORed with a corresponding byte from the encryption key. This operation ensures that the ciphertext is dependent on the key, making it difficult to decrypt without the key.
Strengths and Weaknesses of AES
AES is a highly secure encryption algorithm that is resistant to many types of attacks. It is designed to be computationally efficient, which means that it can be used in a wide range of applications without causing significant delays or performance issues.
One of the main strengths of AES is its flexibility. It can be used with key sizes of 128, 192, or 256 bits, depending on the level of security required. It is also resistant to known attacks such as brute-force attacks and differential cryptanalysis.
However, like all encryption algorithms, AES is not completely immune to attacks. There have been some successful attacks on AES, including attacks on certain key schedules and side-channel attacks that exploit weaknesses in the implementation of the algorithm
Applications of AES
AES is used in a wide range of applications, let’s check where AES is most commonly used
- Online banking: AES is used to encrypt sensitive data such as passwords and account numbers in online banking systems.
- E-commerce: AES is used to encrypt credit card information and other sensitive data in e-commerce transactions.
- Government communication: AES is used to encrypt classified information in government communication systems.
- File encryption: AES is used to encrypt files and folders on computers and other storage devices.
- Virtual Private Networks (VPNs): AES is used to encrypt data transmitted over VPNs, ensuring that the data remains secure and confidential.