SHA256 is a SHA-2 algorithm with 256-bit output and broad ecosystem support, making it the practical default for modern integrity verification workflows.
Specifications
Output Size256 bits
StandardFIPS 180-4
Standard Year2015
Origin SHA-256 in the SHA-2 family
Origin Year 2001
Use Cases
—Software download verification
—Message integrity checks
—Blockchain and security tooling
Security Notice
SHA256 is secure for integrity, but use Argon2/bcrypt/scrypt for password storage.
Frequently Asked Questions
SHA256 is designed as a one-way hash function. It is not reversible, but weak input choices can still be guessed via brute-force or dictionary attacks.
SHA-256 is generally faster on 32-bit platforms, while SHA-512 is often faster on 64-bit platforms due to its 64-bit word operations. SHA-256 produces a 256-bit digest versus SHA-512's 512-bit output, making SHA-256 more space-efficient for most applications.
SHA-256 provides 128 bits of security against collision attacks classically. Quantum computers using Grover's algorithm could reduce this to approximately 85 bits. While not immediately broken, NIST recommends transitioning to SHA-384 or SHA-512 for long-term security against quantum threats.