# SHA-3

> set of cryptographic hash functions

**Wikidata**: [Q1190947](https://www.wikidata.org/wiki/Q1190947)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/SHA-3)  
**Source**: https://4ort.xyz/entity/sha-3

## Summary
SHA-3 (Secure Hash Algorithm 3) is a set of cryptographic hash functions and a technical standard standardized by the National Institute of Standards and Technology (NIST). It serves as a successor to SHA-2 and is based on the Keccak algorithm, which was invented by Joan Daemen, Gilles Van Assche, and Guido Bertoni. The standard was officially released on August 5, 2015, though the underlying algorithm dates back to 2008.

## Key Facts
- **Classification:** SHA-3 is a parametrized function family and a technical standard belonging to the broader class of SHA hash functions.
- **Inventors:** The algorithm was created by Joan Daemen, Gilles Van Assche, and Guido Bertoni.
- **Standardization Date:** The technical standard was officially released and became effective on August 5, 2015.
- **Algorithm Inception:** The underlying algorithm was established in 2008.
- **Predecessor:** SHA-3 follows SHA-2, a set of cryptographic hash functions designed by the NSA (inception 2002).
- **Basis:** The design of SHA-3 is based on RadioGatún, a cryptographic hash primitive.
- **Components:** The standard includes the hash functions SHA3-224, SHA3-256, SHA3-384, and SHA3-512, as well as the extendable-output functions SHAKE128 and SHAKE256.
- **Standards Body:** It is maintained by the National Institute of Standards and Technology (NIST).
- **Aliases:** Also known as Keccak, SHA3, and Secure Hash Algorithm 3.

## FAQs
### Q: Who invented SHA-3?
A: SHA-3 was invented by the cryptologists Joan Daemen, Gilles Van Assche, and Guido Bertoni. Joan Daemen is also known for his work as a Belgian cryptologist and mathematician.

### Q: When was SHA-3 officially released?
A: The SHA-3 technical standard was announced and became effective on August 5, 2015, following approval by the Secretary of Commerce as Federal Information Processing Standard (FIPS) 202.

### Q: What is the relationship between SHA-3 and Keccak?
A: SHA-3 is essentially the standard name for the Keccak algorithm. While the terms are often used interchangeably, SHA-3 is the official standard designation given by the National Institute of Standards and Technology, whereas Keccak is the specific algorithm designed by the inventors.

### Q: What hash functions are included in the SHA-3 family?
A: The SHA-3 family includes the fixed-length hash functions SHA3-224, SHA3-256, SHA3-384, and SHA3-512. It also includes SHAKE128 and SHAKE256, which are extendable-output functions (XOFs).

## Why It Matters
SHA-3 matters significantly in the field of cryptography because it provides a robust alternative to the existing SHA-2 standard, ensuring the long-term security of digital data. While SHA-2 remains secure, the development of SHA-3 was driven by the need for diversity in hashing algorithms; should a critical vulnerability ever be discovered in SHA-2 (which shares structural similarities with MD5 and SHA-1), SHA-3 offers a mathematically distinct backup based on a different construction called a sponge function (derived from RadioGatún).

By formally recognizing the Keccak algorithm as FIPS 202, NIST provided a standardized, high-security tool for verifying data integrity, digital signatures, and password storage. Its structure allows for flexibility, supporting not just fixed hash outputs but also extendable-output functions (XOFs) like SHAKE128 and SHAKE256, which can produce hash values of variable lengths. This versatility makes SHA-3 a foundational technology for modern cybersecurity infrastructure.

## Notable For
- **Structural Difference:** Unlike its predecessors (SHA-1 and SHA-2) which use Merkle–Damgård construction, SHA-3 is based on the RadioGatún primitive, utilizing a unique sponge construction.
- **Open Competition:** It was the result of a public competition organized by NIST to find a secure hashing algorithm, contrasting with the NSA-originated design of SHA-2.
- **Versatility:** It is notable for introducing Extendable-Output Functions (XOFs) (SHAKE128 and SHAKE256) alongside standard fixed-length hashes.
- **Pedigree:** It was co-created by Joan Daemen, a prominent Belgian cryptologist also famous for co-designing the Advanced Encryption Standard (AES).

## Body
### Development and Standardization
SHA-3 represents the latest evolution in the Secure Hash Algorithm family. While the algorithm inception dates to 2008, the journey to standardization concluded on August 5, 2015. On this date, the National Institute of Standards and Technology (NIST) released the standard under Federal Information Processing Standard (FIPS) 202. The notice announced the Secretary of Commerce's approval of "FIPS 202, SHA-3 Standard: Permutation-Based Hash and Extendable-Output Functions."

### Technical Design and Origins
The core of SHA-3 is the Keccak algorithm, credited to inventors Joan Daemen, Gilles Van Assche, and Guido Bertoni. The design is heavily based on **RadioGatún**, a cryptographic hash primitive. This lineage distinguishes SHA-3 from the earlier SHA-2 family, which was designed by the National Security Agency (NSA) and established in 2002.

### Family Members and Variants
As a parametrized function family, SHA-3 encompasses several specific instantiations tailored for different security and performance needs. The standard specifies the following components:
*   **Fixed-output functions:** SHA3-224, SHA3-256, SHA3-384, and SHA3-512.
*   **Extendable-output functions (XOFs):** SHAKE128 and SHAKE256.

These functions are widely implemented across software and hardware platforms, reflected by their presence in resources like GitHub topics and Stack Exchange tags.

## Schema Markup
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  "@type": "Thing",
  "name": "SHA-3",
  "description": "A set of cryptographic hash functions and technical standard based on the Keccak algorithm, succeeding SHA-2.",
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## References

1. [NIST Releases SHA-3 Cryptographic Hash Standard](https://www.nist.gov/news-events/news/2015/08/nist-releases-sha-3-cryptographic-hash-standard)
2. [Source](https://www.federalregister.gov/documents/2015/08/05/2015-19181/announcing-approval-of-federal-information-processing-standard-fips-202-sha-3-standard)