Function json_decryptencrypteddata

lightningd/onion_message.c:207–255

AUTODATA(json_command, &injectonionmessage_command);

static struct command_result *json_decryptencrypteddata(struct command *cmd,
							const char *buffer,
							const jsmntok_t *obj UNNEEDED,
							const jsmntok_t *params)
{
	u8 *encdata, *decrypted;
	struct pubkey *path_key, next_path_key;
	struct secret ss;
	struct sha256 h;
	struct json_stream *response;

	if (!param_check(cmd, buffer, params,
			 p_req("encrypted_data", param_bin_from_hex, &encdata),
			 p_req("path_key", param_pubkey, &path_key),
			 NULL))
		return command_param_failed();

	/* BOLT #4:
	 *
	 * - MUST compute:
	 *   - $`ss_i = SHA256(k_i * E_i)`$ (standard ECDH)
	 *...
	 *   - $`rho_i = HMAC256(\text{"rho"}, ss_i)`$
	 * - MUST decrypt the `encrypted_recipient_data` field using $`rho_i`$
	 */
	ecdh(path_key, &ss);

	decrypted = decrypt_encmsg_raw(cmd, &ss, encdata);
	if (!decrypted)
		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
				    "Decryption failed!");

	if (command_check_only(cmd))
		return command_check_done(cmd);

	/* BOLT #4:
	 *
	 *   - $`E_{i+1} = SHA256(E_i || ss_i) * E_i`$
	 */
	blinding_hash_e_and_ss(path_key, &ss, &h);
	blinding_next_path_key(path_key, &h, &next_path_key);

	response = json_stream_success(cmd);
	json_object_start(response, "decryptencrypteddata");
	json_add_hex_talarr(response, "decrypted", decrypted);
	json_add_pubkey(response, "next_path_key", &next_path_key);
	json_object_end(response);
	return command_success(cmd, response);
}

static const struct json_command decryptencrypteddata_command = {
	"decryptencrypteddata",