Message signing, version 1

Status: stable. For signing arbitrary data off chain (the signArbitrary request of Keplr-compatible wallets), for example to prove control of an account to a service. Source: spec/message-signing-v1.md.

Signature

{
  "signatureType": "ml-dsa-87-hybrid",
  "classical": { "keyType": "secp256k1", "publicKey": "<base64>", "signature": "<base64>" },
  "pq": { "algorithmId": 1, "signature": "<base64>" }
}

• Classical part: ADR-36. The account's secp256k1 key signs the amino JSON sign document of MsgSignData { signer, data }, exactly as in Sign In With QoreChain v1 (SHA-256 digest for secp256k1 accounts, KECCAK-256 for eth_secp256k1; 64 bytes r || s, low-S).
• Post-quantum part:

pq.signature = ML-DSA-87.Sign(sk, UTF-8("qorechain-msg-v1|" + chain_id + "|") || data, ctx = "")

data is the raw message bytes. chain_id contains only letters, digits, ., _ and -.

Domain separation

Every ML-DSA-87 signature an account makes on QoreChain starts with a domain of its own, so a signature produced for one purpose cannot be replayed as another. A wallet must never sign raw bytes with the ML-DSA-87 key without one of these prefixes, and must never let a message start with a prefix reserved for another use.

Prefix	Use
qorechain-pqc-hybrid-v2	transaction sign-bytes (Hybrid transaction signing v1)
qorechain-pqc-pop-v1|	proof of possession at key registration
qorechain:pqc:recovery:v1	account recovery
qorechain-svm-auth-v2	SVM lane authorization
qorechain-siwq-v1|	Sign In With QoreChain (Sign In With QoreChain v1)
qorechain-msg-v1|	this specification

Verification

1. The classical public key derives to signer under keyType, and the ADR-36 signature verifies.
2. The ML-DSA-87 signature verifies under the key registered on chain for signer (/qorechain/pqc/v1/account/{address}), over the bytes above with the expected chain id.

Test vectors

vectors/qoresign-v1.json, field message. See Test vectors.