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Add hybrid signing to a Keplr-compatible wallet

QoreChain's native lane refuses a transaction from an account with a registered ML-DSA-87 key unless the transaction also carries that key's signature. A Keplr-compatible wallet (Keplr, Leap, Cosmostation and others that implement signDirect) produces the secp256k1 part; the ML-DSA-87 part has to come from whoever holds the post-quantum key.

There are two ways to add it.

Option A: the wallet holds both keys (QoreSign)​

The wallet derives the ML-DSA-87 key next to the secp256k1 key and adds the layer before it signs.

import { deriveCanonicalPqKey, signPqLayer } from "@qorechain/qoresign";

// at account creation or import, from the same mnemonic and address
const pqKey = deriveCanonicalPqKey({ mnemonic, address });

// inside signDirect(signerAddress, signDoc):
const { bodyBytes } = signPqLayer({
  chainId: signDoc.chainId,
  bodyBytes: signDoc.bodyBytes,
  authInfoBytes: signDoc.authInfoBytes,
  pqKey,
});
const finalDoc = { ...signDoc, bodyBytes }; // sign this with the secp256k1 key, as for any Cosmos SDK chain

Rules that keep the user safe:

  • Show the user the messages and fee from bodyBytes / authInfoBytes before signing, the same as for any signDirect request. The ML-DSA-87 signature covers the fee.
  • When a dApp sends a body that already carries a PQC layer, check it with assertPqLayerMatchesRegisteredKey (from @qorechain/qoresign/network) before adding your classical signature; a layer that does not verify protects nothing.
  • Register the key once per account with buildRegisterPqKeyMessage, signed in classicalOnly mode (see examples/register-and-send and Registration).
  • After broadcast, read the committed transaction back and call evaluateLayerState; downgraded means the layer did not reach the chain.

Option B: the dApp holds the post-quantum key (@qorechain/wallet-adapter)​

When the wallet cannot be changed, a dApp can use @qorechain/wallet-adapter: it adds the ML-DSA-87 layer to the body and then asks the unchanged wallet for an ordinary signDirect signature. The post-quantum key then lives with the dApp or a companion signer, not in the wallet. QoreSign and the adapter produce the same bytes for the same keys.

Chain registration for Keplr​

Suggest the chain with experimentalSuggestChain using the published chain descriptors: chain ids qorechain-vladi (mainnet) and qorechain-diana (testnet), bech32 prefix qor, coin type 118, fee denom uqor with 6 decimals and a minimum gas price of 0.1. Public endpoints: https://rpc.qore.host and https://api.qore.host (mainnet), https://rpc-testnet.qore.host and https://api-testnet.qore.host (testnet).