What Are Cryptographic Hashes Used For?
- File integrity — Verify a downloaded file matches the source
- Password storage — Hash passwords before storing (with proper salting + bcrypt/argon2)
- Digital signatures — Sign documents and verify they haven't been tampered with
- Blockchain — Block hashes link the chain together
- Deduplication — Find identical files quickly
Which Algorithm Should I Use?
- MD5 / SHA-1 — Broken for security purposes, but still common for file checksums where collision resistance isn't critical
- SHA-256 — Modern default. Used in Bitcoin, SSL/TLS certificates, and most security applications
- SHA-384 / SHA-512 — Stronger variants for high-security applications