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Hash Algorithm Guide: MD5, SHA-256 & Cryptographic Hashing Explained
2026-06-25 ยท 8 min read
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What Is a Hash Function?
A hash function takes an input of any size and produces a fixed-size output - the hash digest. Even the tiniest change in input yields a completely different hash, making them ideal for data integrity verification.
Key Properties of Cryptographic Hashes
- Deterministic - The same input always produces the same hash.
- Pre-image resistance - Given a hash, it is computationally infeasible to find the original input. This is why hashing is one-way.
- Avalanche effect - Changing one bit of input changes roughly 50% of the output bits.
- Collision resistance - It should be infeasible to find two different inputs that produce the same hash.
Popular Hash Algorithms
- MD5 - 128-bit. Broken - do not use for security. Still useful for non-cryptographic checksums.
- SHA-1 - 160-bit. Deprecated. Git still uses SHA-1 but is migrating to SHA-256.
- SHA-256 - 256-bit. The current industry standard. Used in TLS, Bitcoin, and password hashing frameworks.
- SHA-512 - 512-bit. Higher security margin. Faster than SHA-256 on 64-bit processors.
Real-World Use Cases
- File integrity - Verify downloaded files with SHA-256 checksums.
- Password storage - Websites hash passwords with bcrypt or Argon2 (not plain SHA-256!).
- Blockchain - Bitcoin mining is essentially computing SHA-256 hashes.
- Git version control - Every commit is identified by a SHA-1 hash of its contents.
Try all these algorithms at the ToolHub Hash Generator.
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