Module ecdsa 

ECDSA signature verification precompile for the Miden VM.

This module provides both execution-time and verification-time support for ECDSA signature verification using the secp256k1 curve with Keccak256 hashing.

Architecture

Event Handler (Execution-Time)

When the VM emits an ECDSA verification event requesting signature validation, the processor calls EcdsaPrecompile which reads the public key, message digest, and signature from memory, performs the verification, provides the boolean result via the advice stack, and logs the request data for deferred verification.

Precompile Verifier (Verification-Time)

During verification, the PrecompileVerifier receives the stored request data (public key, digest, signature), re-performs the ECDSA verification, and generates a commitment Rpo256(Rpo256(Rpo256(pk) || Rpo256(digest)) || Rpo256(sig)) with a tag containing the verification result that validates the computation was performed correctly. Here pk, digest, and sig are hashed as u32‑packed field elements before being merged.

Commitment Tag Format

Each request is tagged as [event_id, result, 0, 0] where result is 1 for valid signatures and 0 for invalid ones. This allows the verifier to check that the execution-time result matches the verification-time result.

Data Format

• Public Key: 33 bytes (compressed secp256k1 point)
• Message Digest: 32 bytes (Keccak256 hash of the message)
• Signature: 66 bytes (implementation‑defined serialization used by miden_crypto::dsa::ecdsa_k256_keccak::Signature). When packed into u32 elements for VM memory, the final word contains 2 zero padding bytes (since 66 ≡ 2 mod 4).

Structs

EcdsaPrecompile

ECDSA signature verification precompile handler.

EcdsaRequest

ECDSA signature verification request containing all data needed to verify a signature.

Constants

ECDSA_VERIFY_EVENT_NAME

Qualified event name for the ECDSA signature verification event.