Keccak

What Is Keccak?

Guido Bertoni, Joan Daemen, Michal Peeters, and Gilles Van Assche created Keccak (pronounced "ketchak"), a versatile cryptographic function. Although Keccak can be used for other things, it is mainly renowned as a hash function that provides higher levels of security than prior hash algorithms such as SHA-1 and SHA-2. 

SHA refers to a set of cryptographic hash algorithms issued by the US National Institute of Standards and Technology (NIST). SHA-1 and SHA-2 were both developed by the US National Security Agency (NSA) and hence had a similar structure. 

Despite Keccak providing the same output sizes (hash lengths) as SHA-2, its operating process is fundamentally different. Nonetheless, Keccak is a member of the SHA family and is frequently referred to as SHA-3.

Why Was There a Need for Keccak?

Theoretical assaults on SHA-1 were carried out in 2004 and made public in 2005. As a result, NIST declared SHA-2 as the newly revised hash function to be used a few years later, in 2011. However, the transition from SHA-1 to SHA-2 was slow, and it wasn't until early 2017 that a considerable number of developers and computer scientists made the switch. 

Shortly after, in February 2017, Google released a successful SHA-1 collision attack; since then, SHA-1 is no longer regarded as secure, and its use is not recommended. After NIST launched a public competition and vetting process for a new cryptographic hash function that may solve the potential weaknesses of the prior SHA-1 and SHA-2, the Keccak function (SHA-3) began to be developed around 2007. 

Although no substantial SHA-2 attacks have yet been shown, hash functions are believed to be cracked over time and will take years to establish a new standard function. Taking this into consideration, as well as the successful assaults against SHA-1 in 2004 and 2005, NIST saw the need to develop a new cryptographic hash algorithm. 

Keccak was deemed the competition's winning algorithm in 2012 and was standardized as the latest addition of the SHA family (hence, SHA-3). NIST chose Keccak because of its novel structure, which was safer and more effective than the other algorithms. Technically, the SHA-3 algorithm is based on sponge functions (or sponge construction), as opposed to the Merkle Damgrd construction used by SHA-1 and SHA-2. 

SHA-2 is still frequently used and deemed secure. For example, SHA-256 is utilized by Bitcoin and several other cryptocurrencies and is critical in the mining process. As it appears to be anything but being successfully attacked, we may see increased adoption of SHA-3 in the future. Nonetheless, as the area of cryptography evolves and new weaknesses are uncovered, more cryptographic hash algorithms will be developed in the coming years.