Does this mean Whirlpool has a known collision weakness?

No, quite the opposite, and that's worth being explicit about. Whirlpool has no known practical collision or preimage attack against its full, standardized version. This tool's truncated 16-24 bit demo works purely because of the birthday paradox applying to any hash function's short truncation, it says nothing about Whirlpool's actual 512-bit collision resistance, which remains intact as far as public cryptanalysis has shown.

Why include Whirlpool in a set of tools alongside broken hashes like MD2/MD4/MD5?

Specifically to make the contrast clear: MD2, MD4, and MD5 all have real, documented full-length collision breaks found through differential cryptanalysis, while Whirlpool doesn't. Yet this identical truncated-collision demo works just as fast against all four algorithms, because the birthday paradox operates on the truncation length you choose, not on whether the underlying algorithm's full-length collision resistance happens to be broken.

Why is finding a truncated collision so much faster than a full one?

The birthday paradox: finding any collision (not against a specific target, just any two inputs that happen to match) needs roughly sqrt(2^N) attempts for an N-bit space, not 2^N. At 16 bits that's around 256 expected attempts, at 24 bits around 4,096, both trivial for a browser tab. Scaled up to Whirlpool's full 512-bit output, brute-force search would need roughly 2^256 attempts, so astronomically infeasible that it's meaningless to even compare it to any real-world computational resource.

Why is this the only async collision generator in this category?

Because Whirlpool itself is computed via a WebAssembly module (the same reason this category's Whirlpool Hash Calculator and Whirlpool Hash Reverser are also async), so each candidate hash in the search needs to be awaited individually rather than computed synchronously in a tight loop, unlike the MD2/MD4/MD5 collision generators.

Whirlpool Collision Generator - Live Truncated-Digest Birthday Demo

Overview

Introduction

Whirlpool has no known practical collision or preimage attack against its full, standardized version, unlike MD2, MD4, and MD5 elsewhere in this category, and this tool's truncated demo doesn't change that.

It runs a genuine, live birthday-attack search: random short strings, hashed with Whirlpool via the same WebAssembly implementation this category's Whirlpool Hash Calculator uses, until two different ones share a truncated digest prefix at a bit length you choose, clearly and repeatedly labeled as operating on a truncated digest, nowhere close to Whirlpool's full 512-bit output.

What Is Whirlpool Collision Generator?

A live collision-finding demo built on the birthday paradox: it generates random 6-10 character alphanumeric strings, hashes each with Whirlpool, and tracks the first N/4 hex characters (N bits) of every digest seen.

As soon as two different inputs produce the same truncated prefix, the search stops and reports both inputs, their full Whirlpool digests, and the shared truncated prefix, a real, verifiable truncated collision computed entirely in your browser.

How Whirlpool Collision Generator Works

For your chosen bit length (16, 20, or 24), the tool repeatedly generates a random short string via crypto.getRandomValues, computes its Whirlpool digest asynchronously via WebAssembly, and truncates that digest's hex representation to the first bitLength/4 characters.

Each truncated prefix is checked against every prefix seen so far in this search; a match from two distinct inputs ends the search successfully, while a cap of 200,000 attempts (far beyond what the birthday bound requires) prevents the browser from ever hanging if something goes wrong.

When To Use Whirlpool Collision Generator

Use this to see the birthday paradox in action on a hash function with genuinely no known full-length collision weakness, a useful contrast against this category's MD2/MD4/MD5 collision generators.

Don't use this as evidence of any weakness in Whirlpool; the truncated collision this tool finds says nothing about Whirlpool's full 512-bit collision resistance, which remains unbroken as far as public cryptanalysis shows.

Often used alongside Whirlpool Hash Calculator, MD5 Collision Generator and Whirlpool Hash Reverser.

Features

Advantages

Every result is a genuine, live, verifiable computation, not a canned or faked example.
Makes the birthday paradox's counterintuitive speed concrete and checkable in seconds, even against an algorithm with strong full-length security.
Clearly and repeatedly labeled as a truncated-digest demo, avoiding any suggestion that Whirlpool's collision resistance is compromised.

Limitations

Only demonstrates truncated collisions (16-24 bits); Whirlpool's full 512-bit collision resistance is untouched by this or any known brute-force technique.
Bit length is capped at 24 in this tool's UI to keep search time reasonable in a browser tab; the birthday bound would still make higher truncations feasible, just with proportionally more attempts and WebAssembly calls.
Slightly slower per attempt than the MD2/MD4/MD5 collision generators, since each candidate hash is awaited individually through a WebAssembly call rather than computed synchronously.

Examples

A 16-bit truncated collision

Input

bit length: 16

Output

Two different random inputs whose Whirlpool digests share the same first 4 hex characters (16 bits), found live in a few hundred attempts.

Because live results are randomized every run, the exact colliding inputs and digests differ each time you use the tool; this describes the shape of the result rather than one fixed example.

Best Practices & Notes

Best Practices

Try increasing the bit length from 16 to 20 to 24 to feel how attempt counts scale roughly with sqrt(2^N), not with N or 2^N directly.
Use this tool's result specifically to contrast against the MD2/MD4/MD5 Collision Generators: identical truncated-search technique, very different underlying full-length security stories.
Never cite a truncated collision found here as evidence of any weakness in Whirlpool itself.

Developer Notes

Built on this category's shared findTruncatedCollisionAsync() helper (in find-truncated-collision.ts), which this tool calls with the existing async calculateWhirlpoolHash function, awaiting each candidate hash individually. Random candidate strings (6-10 alphanumeric characters) are generated via crypto.getRandomValues, never Math.random(). A 200,000-attempt cap prevents the browser from ever hanging, though the birthday bound (~sqrt(2^N), roughly 256-4,096 expected attempts for the 16-24 bit range this tool offers) means that cap should essentially never be reached.

Whirlpool Collision Generator Use Cases

Demonstrating the birthday paradox's counterintuitive search speed live and verifiably, even against a strong hash function
Contrasting truncated-collision search behavior against algorithms with (MD2/MD4/MD5) and without (Whirlpool) known full-length collision breaks
Teaching that a fast truncated-collision demo says nothing about an algorithm's actual full-length security
Cryptography coursework covering birthday attacks and the distinction between truncated and full-length collision resistance

Common Mistakes

Assuming a fast truncated collision here implies any weakness in Whirlpool's full-length collision resistance; it doesn't, the birthday paradox applies to any hash function at a short enough truncation.
Expecting this tool to run as fast per-attempt as the synchronous MD2/MD4/MD5 collision generators; Whirlpool's WebAssembly computation is awaited per candidate, adding overhead.
Confusing this brute-force birthday demo with actual Whirlpool cryptanalysis; no comparable full-length attack against Whirlpool is known to exist.

Tips

Run the MD5 Collision Generator on the same bit length right after this one, notice the search feels similarly fast despite MD5 being broken at full length and Whirlpool not being, that's the birthday paradox's point.
For Whirlpool's actual, non-truncated digest, use this category's Whirlpool Hash Calculator instead.

Whirlpool Collision Generator