Crate synedrion

Crate synedrion 

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§Synedrion

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§A threshold signing library based on the CGGMP’24 scheme.

WARNING: the library is a work in progress (see Issues), and has not been audited. Use at your own risk.

This library is an implementation of a scheme described in “UC Non-Interactive, Proactive, Threshold ECDSA with Identifiable Aborts” by R. Canetti, R. Gennaro, S. Goldfeder, N. Makriyannis, and U. Peled. Specifically, we are using the scheme as specified in the preprint at https://eprint.iacr.org/2021/060, revision 2024-10-21.

§Protocols

The library implements the following protocols from the paper:

  • ECDSA Key-Generation - generates the initial secret key shares and distributes the public counterparts between the nodes;
  • Auxiliary Info. & Key Refresh - generates updates to the secret key shares and auxiliary information required for ZK proofs;
  • Auxiliary Info - the protocol above without the key refresh, only generating the auxiliary info;
  • ECDSA Presigning - performs all the signing calculations that do not depend on the message that is being signed;
  • ECDSA Signing - finalizes signing given a pre-hashed message.
  • ECDSA Interactive Signing - the two protocols above chained one after the other acting as a single protocol. Note that currently Presigning and Signing are not available separately to ensure we can generate provable evidence on Signing faults (which requires transcript from Presigning).
  • Threshold Key Resharing - technically not a part of the CGGMP’24 proper, but needed to enable threshold functionality.

All the protocols support identifiable aborts where specified by the paper, and where possible, a self-contained malicious behavior evidence will be returned, so that it can be published.

The following components are work in progress:

§High-level API

The library uses manul as a framework for running the protocols. All the protocols expose a type implementing EntryPoint and can be executed via Session.

See manul docs for general information on how to execute protocols in production or development environment, and how to handle errors.

§Features

k256: Secp256k1 parameters using k256 crate. See the [k256] module.

dev: Non-secure development parameters using tiny-curve crate. See the [dev] module.

bip32: enables BIP32 support for ThresholdKeyShare.

Re-exports§

pub use signature;

Structs§

AuxGen
An entry point for the AuxGenProtocol.
AuxGenAssociatedData
Associated data for AuxGen protocol.
AuxGenProtocol
A protocol for generating auxiliary information for signing.
AuxInfo
The result of the AuxGen protocol.
InteractiveSigning
An entry point for the InteractiveSigningProtocol.
InteractiveSigningAssociatedData
Associated data for InteractiveSigning protocol.
InteractiveSigningProtocol
A protocol for creating all the data necessary for signing that doesn’t require knowing the actual message being signed.
KeyInit
An entry point for the KeyInitProtocol.
KeyInitAssociatedData
Associated data for KeyInit protocol.
KeyInitProtocol
A protocol that generates shares of a new secret key on each node.
KeyRefresh
An entry point for the KeyRefreshProtocol.
KeyRefreshAssociatedData
Associated data for KeyRefresh protocol.
KeyRefreshProtocol
A protocol for generating auxiliary information for signing, and a simultaneous generation of updates for the secret key shares.
KeyResharing
An entry point for the KeyResharingProtocol.
KeyResharingProtocol
A protocol for modifying the set of owners of a shared secret key.
KeyShare
The result of the KeyInit protocol.
KeyShareChange
The result of the Auxiliary Info & Key Refresh protocol - the update to the key share.
NewHolder
New share data.
OldHolder
Old share data.
RecoverableSignature
A wrapper for a signature and public key recovery info.
ThresholdKeyShare
A threshold variant of the key share, where any threshold shares our of the total number is enough to perform signing.

Traits§

SchemeParams
Signing scheme parameters.

Type Aliases§

PrehashedMessage
Prehashed message to sign.