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SHA-256

Convert text or file into a SHA-1 hash

SHA-256 Hash Generator

What is SHA-256​

SHA-256 (Secure Hash Algorithm 256)

Overview:
SHA-256 is a cryptographic hash function and part of the SHA-2 family, published by NIST in 2001. It produces a longer, more secure digest than SHA-1 and is widely used in modern security applications.

Output Size:

  • Produces a 256-bit (32-byte) hash.
  • Usually represented as a 64-character hexadecimal string.

Internal Structure:

  • Processes data in 512-bit blocks.
  • Uses 64 rounds of operations per block.
  • Maintains eight 32-bit words as its internal state.
  • Operations include bitwise logical functions, modular addition, and circular shifts.
  • Based on the Merkle–Damgård construction like SHA-1, but with enhanced security and complexity.

Cryptographic Properties:

  • Deterministic: the same input always produces the same output.
  • Strong avalanche effect: tiny input changes result in drastically different output.
  • One-way: infeasible to reverse the hash to recover the original input.
  • Collision-resistant: no practical collisions are known; designed to withstand attacks up to 2^128 complexity.

Security:

  • Considered secure for digital signatures, TLS certificates, file integrity verification, and blockchain applications.
  • Widely used in HMAC constructions for message authentication.

Performance:

  • Efficient on both 32-bit and 64-bit processors.
  • Slightly slower than SHA-1 due to longer hash and more rounds, but much stronger security.

Common Use Cases:

  • TLS/SSL certificates and HTTPS connections.
  • Cryptocurrencies and blockchain systems (e.g., Bitcoin uses double SHA-256).
  • File integrity checks and digital signatures.
  • HMAC for secure message authentication.