What Is SHA-256?

SHA-256 (Secure Hash Algorithm 256-bit) is a member of the SHA-2 cryptographic hash family designed by the NSA. It produces a 256-bit (64-character hexadecimal) hash value and is considered cryptographically secure as of 2025.

Where Is SHA-256 Used?

  • ⛓️ Bitcoin and blockchain — Bitcoin's proof-of-work algorithm is based entirely on SHA-256.
  • 🔐 SSL/TLS certificates — HTTPS connections use SHA-256 for certificate signatures.
  • 📦 Software distribution — GitHub, npm, and all major repositories publish SHA-256 checksums for downloads.
  • 🗝️ JWT signatures — HS256 (HMAC-SHA256) is the most common JWT signing algorithm.
  • 💾 Git commits — Git historically used SHA-1; newer versions support SHA-256.

How to Verify a File's SHA-256 Checksum

When you download software, always verify the checksum to confirm the file hasn't been tampered with:

  1. Download the file and its published SHA-256 checksum.
  2. Use FavorTool SHA-256 Generator to hash the file content.
  3. Compare the generated hash with the published one — they must match exactly.

Any difference, even in a single character, indicates a corrupted or tampered file.

SHA-256 in Passwords — What Not to Do

Despite being cryptographically strong, raw SHA-256 should never be used for password hashing. It's designed to be fast — attackers can try billions of hashes per second. Always use dedicated password hashing functions: bcrypt, Argon2, or scrypt which are deliberately slow and memory-intensive.

SHA-256 vs SHA-512 — When to Use Which

SHA-256 is sufficient for most applications and performs better on 32-bit systems. SHA-512 produces a 512-bit hash and performs better on 64-bit systems due to 64-bit operations. Both are considered secure. Use SHA-256 by default unless you specifically need the larger hash size.