What is SHA-256?

SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function that takes an input and produces a 256-bit (32-byte) hash value, typically represented as a 64-digit hexadecimal number. It is part of the SHA-2 family, designed by the NSA and published by NIST.

Key Properties:

• One-way function: It's computationally infeasible to determine the original input from the SHA-256 hash.
• Deterministic: The same input will always produce the same SHA-256 hash.
• Collision resistance: It is computationally infeasible to find two different inputs that produce the same SHA-256 hash.
• Avalanche effect: A small change in the input produces a significantly different hash.

Why is SHA-256 important?

SHA-256 is one of the most widely used hash functions in modern cryptography. It is used in:

• TLS/SSL certificates: For digital signatures and certificate verification.
• Blockchain: Bitcoin and other cryptocurrencies use SHA-256 for proof-of-work.
• Password hashing: When combined with proper salting and key derivation (e.g., PBKDF2, bcrypt).
• File integrity: Verifying that files have not been tampered with.

SHA-256 vs SHA-3-256

SHA-256 (part of SHA-2) and SHA3-256 (part of SHA-3) both produce 256-bit hashes but use different internal constructions. SHA-256 uses the Merkle-Damgard construction, while SHA-3 uses the sponge construction. Both are currently considered secure. Consider using the Calculate SHA3-256 tool for the SHA-3 variant.