🔑 MD5 vs 🔐 SHA-256
MD5 vs SHA-256: speed, security, collision resistance, output length, and when to use each. Includes a free online hash generator.
Never use MD5 for security purposes — it is cryptographically broken and vulnerable to collision attacks. Use SHA-256 for password hashing (with bcrypt/Argon2 on top), HMAC signatures, file integrity verification, and any security-sensitive application. MD5 is acceptable only for non-security checksums (e.g., verifying a download).
MD5 vs SHA-256: Side-by-Side Comparison
| Property | MD5 | SHA-256 |
|---|---|---|
| Output length | 128 bits (32 hex chars) | 256 bits (64 hex chars) |
| Speed | Faster | Slightly slower |
| Collision resistance | ❌ Broken (vulnerable) | ✅ Strong |
| Pre-image resistance | ⚠️ Weak | ✅ Strong |
| Cryptographic use | ❌ Not recommended | ✅ Safe for HMAC, signatures |
| Password hashing | ❌ Never use directly | ⚠️ Use bcrypt/Argon2 instead |
| Checksum use | ✅ Acceptable (non-security) | ✅ Better choice |
When to use MD5
- Non-security file checksums (verifying a download is uncorrupted)
- Legacy system compatibility (when you cannot change the algorithm)
When to use SHA-256
- HMAC signatures for API authentication
- File integrity verification in security contexts
- Digital certificates and TLS
- Building blocks for other cryptographic protocols (do NOT use for passwords — use bcrypt or Argon2)
Frequently Asked Questions
Is MD5 broken?
Yes. MD5 is cryptographically broken — researchers have demonstrated practical collision attacks where two different inputs produce the same MD5 hash. This makes it unsuitable for any security purpose. It can still be used for non-security checksums where collisions are not a concern.
Should I use SHA-256 for password hashing?
No — do not use SHA-256 directly for passwords. It is too fast, making brute-force attacks feasible. Use a purpose-built password hashing algorithm like bcrypt, Argon2id, or scrypt, which are designed to be computationally expensive and slow.
What is the difference in output length?
MD5 produces a 128-bit hash (32 hexadecimal characters). SHA-256 produces a 256-bit hash (64 hexadecimal characters). The longer output of SHA-256 contributes to its greater resistance to attacks.