What is Rijndael Encryption?

Encryption is a method of attempting to keep data secure, private, and authentic as it travels from place to place. Whether on paper or over the Internet via email, during a form submission, or during a credit card transaction, encryption helps protect data. The word encryption means “to cause to be hidden,” and encryption works by applying an algorithm, or standardized process, to some data in its readable form — called plaintext — to convert it to an unreadable form — called ciphertext — until it reaches its intended receiver, who unlocks it with a key. Rijndael encryption is one type of encryption algorithm.

It is not clear whether Rijndael should be pronounced /RINE dahl/ or /RAIN dahl/, but it is clear that the word was formed by joining parts of the surnames of the two inventors, Belgian cryptographers Joan Daemen and Vincent Rijmen. Rijmen and Daemen, who had previously worked an encryption algorithm called Square, developed Rijndael encryption in response to a kind of cryptographers’ contest. In 1977, when the security of the Data Encryption Standard (DES) was being questioned, the National Institute of Standards and Technology (NIST) invited cryptographers to create and submit advanced algorithms to form the basis of a new standard. Teams of cryptographers from 11 countries submitted 21 such algorithms: Rijndael encryption was the one selected in 2000.

Rijndael is a block cipher, rather than a streaming cipher, with data being processed in 128 bit blocks. Keys are longer than in previous systems, being 128 bits, 192 bits, and 256 bits. The new standard of which Rijndael encryption is the basis, still in use as of 2010, is Advanced Encryption Standard (AES), sometimes called AES (Rijndael). AES — and therefore Rijndael encryption — is used in the wireless protocol WAP2 (WiFi Protected Access, version 2) and in IPSec (Internet Protocol Security), specifically in IKE (Internet Key Exchange), which is part of IPSec. IKE is a method for key exchange.

At least partly due to faith in Rijndael encryption, AES has been adopted for important data tranfers by several organizations. In 2000, the government of the United States began using AES for encrypting sensitive, unclassified documents. In 2003, the National Security Agency (NSA) of the US approved the use of the highest bit keys to encrypting top secret documents. Also in 2003, the New European Schemes for Signatures, Integrity, and Encryption (NESSIE) consortium agreed to adopt AES. As with any algorithm, there are ongoing attempts to crack Rijndael encryption by both security experts and those who wish to exploit it.