A workspace containing Poseidon hash implementations for different use cases, built on top of plonky3 field arithmetic.

This workspace contains two crates:

Pure Rust implementation of the Poseidon hash function without any external dependencies beyond plonky3 and plonky2.

• No-std compatible: Works in embedded and constrained environments
• Pure cryptography: No blockchain or Substrate-specific dependencies
• Circuit-compatible: Padding behavior matches zero-knowledge circuit implementations
• NOT CONSTANT TIME: Poseidon2 implementation could reveal hash inputs via timing attacks

Substrate-compatible wrapper that adds codec traits and blockchain-specific functionality.

• Substrate integration: Implements required traits for use in Substrate/Polkadot projects
• Codec support: Implements Encode, Decode, and TypeInfo traits
• Serde support: Optional serialization support
• Storage hashing: Specialized functions for Quantus storage operations

See respective README.md and README.md for more details.

The implementation is optimized for:

• Circuit compatibility (consistent padding)
• No-std environments
• Deterministic behavior across platforms
• Memory efficiency in constrained environments

• Implements the standard Poseidon2 permutation
• Constants are verifiably random, based on pi and ChaCha20
• Circuit-compatible padding
• Variable length padding consistent with original paper
• Code is roughly constant time, as indicated by dudect t-scores < 5. There are no branches in the processing of blocks, so we do not expect any side-channel attacks to reveal the contents of the preimage. There is a small amount of branching in the padding functions, but this should only depend on the length of the input, not the contents.

MIT-0

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests
5. Ensure all tests pass
6. Submit a pull request

• qp-poseidon-core - The underlying pure cryptographic implementation
• parity-scale-codec - Substrate's encoding library
• qp-zk-circuits - The underlying zero-knowledge circuit library
• plonky3 - The underlying field arithmetic library