SHA-256 vs SHA-512
Both are members of the SHA-2 family and are cryptographically secure. The choice between them comes down to security margin requirements, performance on your hardware, and compatibility.
Comparison
| SHA-256 | SHA-512 | |
|---|---|---|
| Output length | 256 bits (64 hex chars) | 512 bits (128 hex chars) |
| Security level | ~128-bit equivalent | ~256-bit equivalent |
| Speed on 64-bit CPU | Fast | Faster (due to 64-bit word size) |
| Speed on 32-bit / mobile | Faster | Slower |
| Compatibility | Ubiquitous (TLS, JWT default, Bitcoin) | Less common |
| Collision resistance | Extremely strong | Even stronger |
When SHA-256 is the right choice
- TLS/SSL certificates — the web standard
- JWTs using HS256 or RS256 — most common algorithm
- File integrity verification and checksums
- Bitcoin and most blockchain applications
- When compatibility with existing systems is required
When SHA-512 makes sense
- Applications demanding maximum security margin beyond current attack capabilities
- 64-bit server environments where SHA-512 is actually faster than SHA-256
- Password hashing foundations (though argon2/bcrypt should be the outer layer)
- Digital signatures requiring the highest assurance level
Important: don't use SHA for passwords
Neither SHA-256 nor SHA-512 should be used directly to hash passwords. They're too fast — an attacker can compute billions per second. Use bcrypt, scrypt, or argon2id for password storage, which are intentionally slow.
Frequently Asked Questions
Is SHA-512 more secure than SHA-256?
Marginally, but SHA-256 is already far beyond what any known attack can break. For practical applications, the difference is negligible.
What about SHA-1 and MD5?
Both are broken for security purposes. MD5 and SHA-1 collisions can be generated. Only use them for non-security checksums where you need legacy compatibility.
Which does JWT use by default?
HS256 (HMAC with SHA-256) is the most common JWT algorithm. RS256, ES256, and PS256 are also SHA-256 based.