mlabs-haskell/plutus-secp256k1-interop

SECP256k1 signature scheme glue to interoperate with Plutus on-chain primitives

plutus-secp256k1-interop

What is this?

A collection of helpers to convert 'external' representations of SECP256k1-curve signature scheme components (which are suitable for serialization and passing around) to 'internal' representations of those same components (which are suitable for passing to Plutus primitives).

Which representations do you support?

Currently, we support all of the following:

• DER-encoded ECDSA scheme public keys
• DER-encoded ECDSA scheme signatures
• BIP-340-compatible Schnorr scheme public keys

How do I use this?

The example below assumes you've received a DER-encoded public key (derPK) and signature (derSig) from somewhere else.

{-# LANGUAGE NoImplicitPrelude #-}

import Plutus.SECP256K1.Interop (
  revealEcdsaPubkeyState,
  revealEcdsaSignatureState,
  decodeDERPubkey,
  decodeDERSignature
  )
import PlutusTx.Builtin (
  toBuiltin,
  verifyEcdsaSecp256k1Signature
  )
import Data.ByteString (ByteString)
import Plutus.Prelude

tryAndVerify :: 
  ByteString -> 
  ByteString -> 
  ByteString -> 
  Bool
tryAndVerify derPK derSig messageHash = case go of 
  Nothing -> False -- parsing didn't go to plan
  Just (internalPK, internalSig) -> 
    verifyEcdsaSecp256k1Signature (toBuiltin internalPK) 
                                  (toBuiltin messageHash)
                                  (toBuiltin internalSig)
  where
    go :: Maybe (ByteString, ByteString)
    go = do
      internalPK <- revealEcdsaPubkeyState <$> decodeDERPubkey derPK
      internalSig <- revealEcdsaSignatureState <$> decodeDERSignature derSig
      pure (internalPK, internalSig)

What can I do with this?

The code is licensed under Apache 2.0; check the LICENSE file for details.