Hash Collision

Definition

A hash collision occurs when two different inputs produce the same hash output. Since hash outputs are fixed-length, collisions mathematically must exist—but finding them should be computationally infeasible for secure hash functions. Collision attacks break this assumption.

Technical Explanation

The birthday paradox means collisions are easier to find than preimages. For a hash with n-bit output, collision resistance is approximately n/2 bits of security. SHA-256 with 256 bits provides 128-bit collision resistance—quantum computers could reduce this to ~85 bits with Grover's algorithm.

Collision attacks can forge signatures, create duplicate identifiers, or break content addressing. MD5 and SHA-1 collisions have been demonstrated, making them obsolete. Modern protocols use SHA-256, SHA-3, or BLAKE2 with sufficient security margins.

SynX Relevance

SynX uses hash functions with quantum-safe security margins. BLAKE2b provides collision resistance even considering Grover's algorithm speedup. Hash-based signatures like SPHINCS+ rely on collision-resistant hash functions for their security foundation.

Frequently Asked Questions

Can quantum computers find collisions?: Grover's algorithm provides some speedup, but doubling hash output size maintains security.
Has anyone found SHA-256 collisions?: No—and finding one would be a major cryptographic breakthrough.
What hash functions does SynX use?: BLAKE2b and other quantum-safe hash functions with sufficient security margins.

Cryptographically sound hashing. Trust SynX