zkHash: Zero-Knowledge Hash Verification

An experiment consisting of a collection of zero-knowledge systems for proving and verifying SHA-1 and SHA-256 hash computations. For now, using both RISC Zero and SP1 proving systems.

One possible application could be for someone with a SHA-1 hash to look up for an equivalent SHA-256 without having the data at hand.

DISCLAIMER: DO NOT USE IN PRODUCTION (this is just a toy project without any audit)

Implementations

RISC Zero Implementation (risc0-sha2+sha1/)

A RISC Zero zkVM program that computes SHA-1 and SHA-256 hashes with proof generation and verification.

Architecture:

• Host (host/): Rust application that generates and verifies proofs
• Guest (methods/guest/): zkVM program that computes hashes inside the zero-knowledge environment
• Methods (methods/): Build configuration and generated zkVM bytecode

Requirements:

• Rust (latest stable)
• RISC Zero toolchain

SP1 Implementation (sp1-sha2+sha1/)

An SP1 program that computes SHA-1 and SHA-256 hashes with support for core proofs and EVM-compatible proofs.

Architecture:

• Program (program/): SP1 program that performs hash computations
• Script (script/): Proof generation and verification scripts
• Lib (lib/): Shared library code

Requirements:

• Rust (latest stable)
• SP1 toolchain

Quick Start

RISC Zero

cd risc0-sha2+sha1
./build.sh

# Generate and verify proof
cat data.bin | ./target/release/host prove > proof.bin
cat proof.bin | ./target/release/host verify

SP1

cd sp1-sha2+sha1/script

# Execute program
cargo run --release -- --execute

# Generate SP1 core proof
cargo run --release -- --prove

# Generate EVM-compatible proof (requires 16GB+ RAM)
cargo run --release --bin evm -- --system groth16

How it Works

1. Proof Generation: The host/script reads input data and sends it to the zkVM program
2. zkVM Execution: The program commits the data size and computes SHA-1 and SHA-256 hashes
3. Proof Creation: The zkVM generates a cryptographic proof that the hash computations were performed correctly
4. Verification: The verifier checks proof validity and compares zkVM-computed hashes with locally computed hashes

Security Properties

• Zero-Knowledge: The input data remains private; only the hash outputs are revealed
• Soundness: Invalid computations cannot produce valid proofs
• Completeness: Valid computations always produce verifiable proofs

License

Licensed under the Apache License, Version 2.0.