bcrypt vs Argon2
Differences, use cases, and when to use each
Both are password hashing algorithms designed to be slow. bcrypt is the established standard (1999). Argon2 is the newer standard (2015 PHC winner) with memory-hardness that resists GPU and ASIC attacks better.
Quick Comparison
| Feature | bcrypt | Argon2 |
|---|---|---|
| Age | 1999 (established) | 2015 (modern) |
| Memory Hardness | No (CPU-only) | Yes (configurable memory) |
| GPU Resistance | Moderate | Strong (memory-bound) |
| Configuration | Work factor (rounds) | Time, memory, parallelism |
| Max Password Length | 72 bytes | No practical limit |
When to Use Each
When to Use bcrypt
Use bcrypt when it's already in your stack, when using older systems, or when Argon2 isn't available. bcrypt remains secure and is widely supported.
When to Use Argon2
Use Argon2 for new projects. Its memory-hardness provides better protection against GPU-based cracking, and it has no password length limitation.
Pros & Cons
bcrypt
Battle-tested for 25+ years
Available in every language
Well-understood security
72-byte password limit
Not memory-hard
Argon2
Memory-hard (GPU resistant)
Configurable memory/time/parallelism
No password length limit
PHC winner
Newer, less battle-tested
Not available in all environments
Verdict
Argon2 for new projects; bcrypt is fine for existing systems. Both are vastly better than MD5, SHA-256, or any fast hash for passwords.