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https://github.com/systemslibrarian/crypto-lab-hash-zoo

Browser-based SHA-256 vs SHA3-256 vs BLAKE3 internals — live avalanche analysis, Merkle-Damgård/sponge/tree construction diagrams, and timing benchmarks. Part of crypto-lab.
https://github.com/systemslibrarian/crypto-lab-hash-zoo

avalanche-effect blake3 browser-demo crypto-lab cryptography-education hash-functions keccak length-extension-attack merkle-damgard sha256 sha3

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Browser-based SHA-256 vs SHA3-256 vs BLAKE3 internals — live avalanche analysis, Merkle-Damgård/sponge/tree construction diagrams, and timing benchmarks. Part of crypto-lab.

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README 

          
# crypto-lab-hash-zoo



## What It Is



Hash Zoo is an interactive side-by-side comparison of three cryptographic hash functions: SHA-256 (Merkle-Damgård construction via `@noble/hashes/sha2`), SHA3-256 (Keccak sponge construction via `@noble/hashes/sha3`), and BLAKE3 (binary tree hash via `@noble/hashes/blake3`). It computes 256-bit digests, measures timing across 100 iterations, and visualizes the avalanche effect — how flipping a single input bit changes roughly half the output bits. The demo also shows SHA-256 Merkle-Damgård padding and SHA-3 rate/capacity parameters to illustrate the structural differences between constructions.



## When to Use It



- **Learning hash function internals.** The avalanche grid and construction diagrams make abstract concepts like sponge absorption and tree-parallel hashing concrete.

- **Comparing performance characteristics.** The timed hash table shows relative throughput of SHA-256, SHA3-256, and BLAKE3 on identical input in the browser.

- **Understanding construction trade-offs.** Side-by-side architecture diagrams clarify why SHA-3 resists length extension while bare Merkle-Damgård does not.

- **Teaching or presenting cryptography.** The live controls (message textarea, bit-position slider) make this suitable for classroom or conference demos.

- **Not for password hashing.** None of these hash functions are memory-hard; use Argon2id or similar KDFs for password storage.

- Do NOT use this as a crypto library — it is a browser teaching demo for comparing hash constructions.



## Live Demo



**[systemslibrarian.github.io/crypto-lab-hash-zoo](https://systemslibrarian.github.io/crypto-lab-hash-zoo/)**



Type or paste any message into the textarea and click "Hash All Three" to see hex output, average timing, and construction metadata for all three algorithms. Use the bit-position slider in Section B to flip a single bit and watch the 16×16 avalanche grid animate which output bits changed. Click "Padding info" to inspect the SHA-256 padded block and SHA-3 rate/capacity split.



## What Can Go Wrong



- **Length extension on bare SHA-256.** Merkle-Damgård hashes expose their internal state as the final digest, allowing an attacker to append data and compute a valid hash without knowing the original message. Use HMAC-SHA256 or switch to SHA-3/BLAKE3.

- **Confusing hash speed with password safety.** SHA-256, SHA3-256, and BLAKE3 are all fast hashes — unsuitable for password storage because an attacker can brute-force billions of guesses per second.

- **Assuming SHA-256 and SHA3-256 are interchangeable.** Despite both producing 256-bit output, their constructions differ fundamentally. Code expecting Merkle-Damgård padding semantics will break if swapped to a sponge hash.

- **Ignoring BLAKE3's tree structure in streaming contexts.** BLAKE3 digests depend on chunk boundaries; streaming implementations must track the tree state correctly or produce wrong hashes.

- **Timing side channels in comparison logic.** Comparing hash digests with early-exit equality checks can leak information about which bytes match; use constant-time comparison in security-critical code.



## Real-World Usage



- **Bitcoin and cryptocurrency.** Bitcoin uses double-SHA-256 for block headers and transaction IDs, relying on Merkle-Damgård's collision resistance.

- **NIST standards and TLS.** SHA-256 is mandated in TLS 1.3 certificate signatures, DNSSEC, and many federal compliance frameworks (FIPS 180-4).

- **Ethereum 2.0 consensus.** The beacon chain uses SHA-256 for its Merkle tree commitments in the proof-of-stake protocol.

- **NIST SHA-3 standard (FIPS 202).** SHA3-256 is standardized as a structural alternative to SHA-2, adopted in protocols requiring sponge-based security guarantees.

- **BLAKE3 file integrity.** The `b3sum` tool and Bao verified streaming use BLAKE3 for fast, parallelizable file checksums and integrity verification.



## How to Run Locally



```bash

git clone https://github.com/systemslibrarian/crypto-lab-hash-zoo

cd crypto-lab-hash-zoo

npm install

npm run dev

```



## Related Demos



- [crypto-lab-babel-hash](https://systemslibrarian.github.io/crypto-lab-babel-hash/) — SHA-256, SHA3-256, BLAKE3, and HMAC in one comparison.

- [crypto-lab-merkle-vault](https://systemslibrarian.github.io/crypto-lab-merkle-vault/) — Merkle trees and inclusion proofs built on SHA-256.

- [crypto-lab-collision-vault](https://systemslibrarian.github.io/crypto-lab-collision-vault/) — MD5/SHA-1 collisions and what breaks when collision resistance fails.

- [crypto-lab-mac-race](https://systemslibrarian.github.io/crypto-lab-mac-race/) — HMAC, CMAC, Poly1305, and GHASH message authentication.

- [crypto-lab-kdf-chain](https://systemslibrarian.github.io/crypto-lab-kdf-chain/) — HKDF, PBKDF2, scrypt, and Argon2id, the memory-hard KDFs hashes should not replace.



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*One of 120+ browser demos in the [Crypto Lab](https://crypto-lab.systemslibrarian.dev/) suite.*



*"So whether you eat or drink or whatever you do, do it all for the glory of God." — 1 Corinthians 10:31*