Function json_signmessagewithkey

wallet/walletrpc.c:1253–1346

AUTODATA(json_command, &sendpsbt_command);

static struct command_result *
json_signmessagewithkey(struct command *cmd, const char *buffer,
			const jsmntok_t *obj UNNEEDED, const jsmntok_t *params)
{
	/* decoding the address */
	const u8 *scriptpubkey;
	const char *message;

	/* from wallet BIP32 */
	struct pubkey pubkey;

	if (!param(
		cmd, buffer, params,
                p_req("message", param_string, &message),
		p_req("address", param_bitcoin_address, &scriptpubkey),
                NULL))
		return command_param_failed();

	const size_t script_len = tal_bytelen(scriptpubkey);

	/* FIXME: we already had the address from the input */
	char *addr;
	addr = encode_scriptpubkey_to_addr(tmpctx, chainparams, scriptpubkey,
					   script_len);

	if (!is_p2wpkh(scriptpubkey, script_len, NULL)) {
		/* FIXME add support for BIP 322 */
		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
				    "Address is not p2wpkh and "
				    "it is not supported for signing");
	}

	if (!hsm_capable(cmd->ld, WIRE_HSMD_BIP137_SIGN_MESSAGE)) {
		return command_fail(
		    cmd, JSONRPC2_INVALID_PARAMS,
		    "HSM does not support signing BIP137 signing.");
	}

	u32 keyidx;
	enum addrtype addrtype;

	/* Use wallet_can_spend which handles both BIP32 and BIP86 addresses */
	if (!wallet_can_spend(cmd->ld->wallet, scriptpubkey, script_len,
			      &keyidx, &addrtype)) {
		return command_fail(
		    cmd, JSONRPC2_INVALID_PARAMS,
		    "Address is not found in the wallet's database");
	}

	/* Derive the pubkey for the found key index */
	if (cmd->ld->bip86_base) {
		bip86_pubkey(cmd->ld, &pubkey, keyidx);
	} else {
		bip32_pubkey(cmd->ld, &pubkey, keyidx);
	}

	/* wire to hsmd a sign request */
	u8 *msg = towire_hsmd_bip137_sign_message(