Comparing Hash Algorithms

Problem

You need to choose a hash algorithm but are unsure how the options compare in speed and security.

Prerequisites

• Understanding of hash functions
• Knowledge of security requirements

Steps

1. 1. Review the security status

   MD5 is broken (collisions in seconds). SHA-1 is broken (SHAttered attack). SHA-256 is secure and widely used. SHA-3 (Keccak) is secure and structurally different from SHA-2. BLAKE2/3 are secure and faster than SHA-2. Choose based on your security needs.

   Input

   algorithms: MD5, SHA-1, SHA-256, SHA-3, BLAKE3

   Output

   secure: SHA-256, SHA-3, BLAKE3

2. 2. Compare performance

   BLAKE3 is the fastest, followed by BLAKE2, then SHA-256 (with hardware acceleration), then SHA-3. MD5 and SHA-1 are fast but broken. For high-throughput hashing, BLAKE3 is the best choice. For compatibility, SHA-256 is the safest bet.

   Input

   1 GB file

   Output

   BLAKE3: ~1 GB/s | SHA-256: ~500 MB/s

3. 3. Choose based on context

   Use SHA-256 for general-purpose hashing and compatibility. Use SHA-3 for NIST compliance or resistance to length-extension attacks. Use BLAKE3 for maximum speed. Use CRC32 only for non-security checksums. Never use MD5 or SHA-1 for security.

   Input

   general purpose

   Output

   SHA-256

Expected result

An informed choice of hash algorithm based on security, speed, and compatibility requirements.

Common errors

Choosing MD5 for speed in a security context

MD5 is broken. Use BLAKE3 if you need speed with security, or SHA-256 for compatibility.

Using SHA-256 where length-extension resistance is needed

SHA-256 is vulnerable to length-extension attacks. Use SHA-3 or HMAC-SHA-256 if this matters.

Troubleshooting

• If speed is critical, benchmark BLAKE3 against SHA-256 with hardware acceleration on your target platform.
• For FIPS compliance, use SHA-256 or SHA-3 only; BLAKE is not FIPS-approved.

Security limits

• Only use hash algorithms that are currently considered secure. MD5 and SHA-1 must not be used for security.
• All hashing is local.