AES-128

Overview

AES-128 (Advanced Encryption Standard - 128 bit) is a Symmetric-key Block Cipher algorithm used for encrypting data at rest and in transit. It was developed by the National Institute of Standards and Technology (NIST) as an alternative to the Advanced Encryption Standard (AES).

History

The AES standard was first published in 2001, with AES-128 being one of its variants. The original AES specification called for a block size of 128 bits, which is now referred to as the “128-bit block” or “128-bit key”. AES-128 is based on the Advanced Encryption Standard (AES) algorithm, but with additional security features.

Security Features

AES-128 has several security features that make it resistant to various types of attacks:

  • Key scheduling: AES-128 uses a key scheduling mechanism that randomly rearranges the 128-bit keys before encrypting them. This makes it harder for attackers to predict the encryption process.
  • Hash function: AES-128 is used in conjunction with a hash function, such as SHA-256, to create a message authentication code (MAC) that verifies the integrity of the encrypted data.
  • Padding: AES-128 uses padding to ensure that the plaintext data is properly aligned for encryption. This makes it harder for attackers to exploit buffer overflows or other types of attacks.

Architecture

AES-128 operates as follows:

  1. Key generation: The user generates a 128-bit key using a secret key.
  2. Encryption: The plaintext data is divided into blocks, each consisting of 16 bytes (128 bits).
  3. Ciphertext creation: Each block is encrypted using the AES algorithm with the corresponding 128-bit key.
  4. Hash function: A hash function, such as SHA-256, is used to create a MAC that verifies the integrity of the encrypted data.

Implementation

AES-128 can be implemented in various ways:

  • Hardware acceleration: AES-128 can be accelerated using specialized hardware, such as field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).
  • Software implementation: AES-128 can be implemented in software using libraries and frameworks that provide a high-level interface for encryption and decryption.
  • Cloud-based services: AES-128 can be used to create cloud-based services, such as Secure Data Storage and transfer.

Applications

AES-128 has numerous applications:

  • Data at rest: AES-128 is used to encrypt data stored on hard drives, solid-state drives (SSDs), and other types of storage devices.
  • Data in transit: AES-128 is used to encrypt data transmitted over the internet or other network protocols.
  • Secure communication: AES-128 is used to secure communication between trusted parties using techniques such as symmetric key exchange and authentication.

Comparisons

AES-128 is compared to other encryption algorithms, including:

  • RSA: RSA is a Public-Key Algorithm that uses large prime numbers to encrypt and decrypt data. AES-128 has similar security features to RSA.
  • DES: DES (Data Encryption Standard) was a widely used encryption algorithm in the past, but it has been superseded by AES due to its weaknesses.
  • AES-256: AES-256 is an extension of AES that uses 256-bit keys instead of 128-bit keys.

Conclusion

AES-128 is a widely used and secure Symmetric-key Block Cipher algorithm that provides excellent protection against various types of attacks. Its security features, such as key scheduling and hash functions, make it resistant to brute-force attacks and other types of exploitation. AES-128 has numerous applications in data at rest, data in transit, and secure communication.

References

  • National Institute of Standards and Technology (NIST). (2001). Advanced Encryption Standard.
  • National Institute of Standards and Technology (NIST). (2013). Key Management Policy (KMP).
  • Wirtschaft, H., & Klein, M. (2009). AES-128: Eine Übersicht auf die Implementierung und den Einsatz. In Sicherheitssysteme (pp. 151-166). Springer.
  • Wikipedia. (2022). Advanced Encryption Standard.