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Understanding Hash Functions: MD5 vs SHA-256
A deep dive into cryptographic hash functions, their differences, and when to use each one in your projects.
What Is a Hash Function?
A hash function takes an input and produces a fixed-size output (the hash or digest). Two properties matter most: determinism and collision resistance.
MD5
MD5 produces a 128-bit (32 hex char) digest. Fast, but cryptographically broken — collision attacks are trivial. Fine for checksums and non-security uses.
SHA-256
SHA-256 is part of the SHA-2 family. Produces a 256-bit digest. No known practical collisions. Used in TLS, JWT signatures, Bitcoin, and most modern security-critical systems.
Rule of Thumb
- Use MD5: file deduplication, cache keys, non-security checksums
- Use SHA-256: passwords (with bcrypt/argon2 on top), digital signatures, data integrity
You can test both instantly using the Hash Generator tool.