What is SHA3-256 Hashing?

SHA3-256 is a cryptographic hash function that belongs to the SHA-3 (Secure Hash Algorithm 3) family. It produces a 256-bit (32-byte) hash value, typically expressed as a 64-character hexadecimal number.

Key characteristics of SHA3-256:

It's a one-way function - you cannot reverse the process to get the original text from the hash
The same input will always produce the same output hash
Even a small change in the input will produce a completely different hash
It was designed by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche as the Keccak algorithm
It was selected by NIST in 2012 as the winner of the SHA-3 competition
It uses a completely different internal structure (sponge construction) than SHA-2, providing algorithm diversity
It's resistant to attacks that might potentially threaten SHA-2 algorithms

Example

Original text

Hello World

SHA3-256 Hash

e167f68d6563d75bb25f3aa49c29ef612d41352dc00606de7cbd630bb2665f51

Common uses of SHA3-256

Applications requiring high security and resistance to quantum computing attacks
Systems that need algorithm diversity (not relying solely on SHA-2 family)
Storing password hashes in security-critical systems
Digital signatures and certificates
Blockchain and cryptocurrency applications
Secure communication protocols

SHA3-256 vs. Other Hash Functions

Feature	SHA3-256	SHA-256	SHA-512
Hash length	256 bits (64 hex chars)	256 bits (64 hex chars)	512 bits (128 hex chars)
Internal structure	Sponge construction	Merkle–Damgård construction	Merkle–Damgård construction
Security	Designed to resist quantum computing attacks	Currently considered secure	Highest security margin in SHA-2 family
Speed	Generally slower than SHA-2	Faster on 32-bit systems	Faster on 64-bit systems
Year introduced	2015 (standardized)	2001	2001

SHA-3 Family

SHA3-256 is part of the SHA-3 family, which includes:

SHA3-224: Produces a 224-bit hash
SHA3-256: Produces a 256-bit hash
SHA3-384: Produces a 384-bit hash
SHA3-512: Produces a 512-bit hash
SHAKE128 and SHAKE256: Extendable-output functions (XOFs) that can produce hash outputs of any desired length

Security Note:

SHA3-256 was designed to provide an alternative to the SHA-2 family, using a completely different internal structure. This diversity is valuable for security, as a vulnerability discovered in one algorithm family is unlikely to affect the other. SHA3-256 is particularly well-suited for applications requiring long-term security or resistance to potential quantum computing attacks.

How SHA3-256 Hashing Works

SHA3-256 hashing follows these steps:

The input text is converted to binary data
The algorithm uses a sponge construction with the Keccak-f[1600] permutation function
The data is "absorbed" into the sponge state (a 5×5×64 bit state array)
The permutation function is applied multiple times, mixing the input data thoroughly
The output is "squeezed" from the state until the desired 256 bits are produced
The hash is typically represented as a 64-character hexadecimal string