🔒SHA-3

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Also known as: Secure Hash Algorithm 3

A Keccak-based family of cryptographic hash functions standardized as SHA-3.

DESCRIPTION

SHA-3 is the NIST-selected successor hash family based on the Keccak sponge construction. It complements SHA-2 by offering a different design, resilience properties, and extendable-output functions (SHAKE). SHA-3 includes fixed-output variants and XOFs useful for customizable digest lengths. It is standardized in FIPS 202 and designed to be robust against known attacks while providing algorithmic diversity.

ALTERNATIVE DEFINITIONS

Wikipedia

SHA-3 is a subset of the Keccak family of cryptographic hash functions and was selected as the winner of the NIST hash function competition.

Notes NIST competition and Keccak lineage.

Source

NIST FIPS 202

This standard specifies the SHA-3 family of permutation-based hash functions.

Formal specification emphasizing permutation-based sponge construction.

Source

Keccak Team

Keccak is a family of sponge functions and the winner of the SHA-3 competition.

Highlights sponge function concept and competition outcome.

Source

RELATED TERMS

Keccak Cryptographic Hash Function Sponge Construction XOF SHAKE128 SHAKE256 NIST FIPS 202 Integrity

COMPETING TERMS

SHA-2

KNOWLEDGE AREAS

Data Security

TARGET AUDIENCE

Cybersecurity Engineer Security Architect Chief Information Security Officer Software Developer Cloud Architect

EXTERNAL SOURCES

• Wikipedia - SHA-3
• NIST - SHA-3 standard specification
• Keccak Team - Keccak family overview
• OWASP - Best practices for hash selection

TOP QUESTIONS

Why did NIST standardize SHA-3 after SHA-2?

SHA-3 offers design diversity via sponge construction and XOFs, providing resilience and flexibility alongside SHA-2.

Category: Relevancy

How does SHA-3 differ from SHA-2 technically?

SHA-3 uses a permutation-based sponge construction, while SHA-2 uses Merkle–Damgård with Davies–Meyer compression functions.

Category: Concepts

What are SHAKE-128 and SHAKE-256?

Extendable-output functions in the SHA-3 family that produce variable-length digests for diverse applications.

Category: Definition

Is SHA-3 faster than SHA-2?

Performance depends on platform and optimization. SHA-2 often remains faster with hardware acceleration; SHA-3 benefits from specific implementations.

Category: Performance

When should I choose SHA-3 over SHA-2?

Use SHA-3 for algorithmic diversity needs, XOF requirements, or compliance specifying SHA-3.

Category: HowTo

Does SHA-3 replace SHA-2?

No. Both coexist; SHA-2 remains widely deployed while SHA-3 provides an alternative design.

Category: Misunderstanding

What standards define SHA-3?

NIST FIPS 202 specifies SHA-3; NIST SPs and drafts describe usage and testing.

Category: Standard

Are there known attacks on SHA-3?

No practical collision attacks on standard variants are known; it remains considered secure.

Category: Risk

Can SHA-3 be used in HMAC?

Yes, HMAC can use SHA-3 variants, forming secure MAC constructions for authentication.

Category: Concepts