Rijndael is free for any use public or private, commercial or non-commercial.[1] The authors of Rijndael used to provide a homepage[2] for the algorithm. Care should be taken when implementing AES in software, in particular around side-channel attacks.
The algorithm operates on plaintext blocks of 16 bytes. Encryption of shorter blocks is possible only by padding the source bytes, usually with null bytes. This can be accomplished via several methods, the simplest of which assumes that the final byte of the cipher identifies the number of null bytes of padding added.
Implementation Considerations
Careful choice must be made in selecting the mode of operation of the cipher. The simplest mode encrypts and decrypts each 128-bit block separately. In this mode, called electronic code book (ECB), blocks that are identical will be encrypted identically; this is entirely insecure. It makes some of the plaintext structure visible in the ciphertext. Selecting other modes, such as using a sequential counter over the block prior to encryption (i.e., CTR mode) and removing it after decryption avoids this problem. Another mode, Cipher Block Chaining (CBC) is one of the most commonly used modes of AES due to its use in TLS. CBC uses a random initialization vector (IV) to ensure that distinct ciphertexts are produced even when the same plaintext is encoded multiple times. The IV can be transmitted in the clear without jeopardizing security. A common practice is to prepend the 16 byte IV to the ciphertext, which gives the decrypter easy access to the IV. Care must be taken to use a new IV for every encryption operation, since otherwise an attacker can recover plaintext.
Current list of FIPS 197 validated cryptographic modules (hosted by NIST)
Current list of FIPS 140 validated cryptographic modules with validated AES implementations (hosted by NIST) – Most of these involve a commercial implementation of AES algorithms. Look for "FIPS-approved algorithms" entry in the "Level / Description" column followed by "AES" and then a specific certificate number.
Microsoft CryptoAPI uses Cryptographic Service Providers to offer encryption implementations. The Microsoft AES Cryptographic Provider was introduced in Windows XP and can be used with any version of the Microsoft CryptoAPI.[3]
tiny-AES-c Small portable AES128/192/256 in C (suitable for embedded systems)
AES-256 A byte-oriented portable AES-256 implementation in C
Solaris Cryptographic Framework offers multiple implementations, with kernel providers for hardware acceleration on x86 (using the Intel AES instruction set) and on SPARC (using the SPARC AES instruction set). It is available in Solaris and derivatives, as of Solaris 10.[4]
LibTomCrypt is a modular and portable cryptographic toolkit that provides developers with well known published block ciphers, one-way hash functions, chaining modes, pseudo-random number generators, public key cryptography and other routines.
AES Dust Compact implementation of AES-128 encryption in C, x86, AMD64, ARM32 and ARM64 assembly.
MSP430 AES Implementation for embedded 16-bit microcontroller
Gladman AES AES code with optional support for Intel AES NI and VIA ACE by Dr. Brian Gladman.
C++ library
Botan has implemented Rijndael since its very first release in 2001
Crypto++ A comprehensive C++ public-domain implementation of encryption and hash algorithms. FIPS validated
C/CUDA library
gKrypt has implemented Rijndael on CUDA with its first release in 2012
C# /.NET
As of version 3.5 of the .NET Framework, the System.Security.Cryptography namespace contains both a fully managed implementation of AES and a managed wrapper around the CAPI AES implementation.
Away RJN Cryptography [5] uses Rijndael Algorithm (NIST AES) 256-bit Data Blocks, Cipher Key and CTR (Counter Mode) for any and all Document or picture encryption in Windows only.
Security for communications in local area networks
IEEE 802.11i, an amendment to the original IEEE 802.11 standard specifying security mechanisms for wireless networks, uses AES-128 in CCM mode (CCMP).
The ITU-TG.hn standard, which provides a way to create a high-speed (up to 1 Gigabit/s) local area network using existing home wiring (power lines, phone lines and coaxial cables), uses AES-128 for encryption.
Miscellaneous
DataLocker Uses AES 256-bit CBC and XTS mode hardware encryption
