Function check_hsm

tools/lightning-hsmtool.c:569–612

Check HSM secret by comparing with backup mnemonic */

/* Check HSM secret by comparing with backup mnemonic */
static void check_hsm(const char *hsm_secret_path)
{
	struct secret file_secret, derived_secret;
	u8 bip32_seed[BIP39_SEED_LEN_512];
	size_t bip32_seed_len;
	const char *mnemonic_passphrase, *mnemonic;
	enum hsm_secret_error err;

	/* Load the hsm_secret (handles decryption automatically if needed) */
	struct hsm_secret *hsms = load_hsm_secret(tmpctx, hsm_secret_path);
	/* Extract first 32 bytes for legacy compatibility */
	memcpy(file_secret.data, hsms->secret_data, 32);

	/* Ask user for their backup mnemonic passphrase */
	printf("Warning: remember that different passphrases yield different "
	       "bitcoin wallets.\n");
	printf("If left empty, no password is used (echo is disabled).\n");
	printf("Enter your mnemonic passphrase: \n");
	fflush(stdout);
	mnemonic_passphrase = read_stdin_pass(tmpctx, &err);
	if (!mnemonic_passphrase)
		errx(EXITCODE_ERROR_HSM_FILE, "Could not read passphrase: %s", hsm_secret_error_str(err));
	if (streq(mnemonic_passphrase, "")) {
		mnemonic_passphrase = NULL;
	}

	/* Ask user for their backup mnemonic using consistent interface */
	mnemonic = read_stdin_mnemonic(tmpctx, &err);
	if (!mnemonic)
		errx(EXITCODE_ERROR_HSM_FILE, "Could not read mnemonic: %s", hsm_secret_error_str(err));

	/* Derive seed from user's backup mnemonic + passphrase */
	if (bip39_mnemonic_to_seed(mnemonic, mnemonic_passphrase, bip32_seed, sizeof(bip32_seed), &bip32_seed_len) != WALLY_OK)
		errx(ERROR_LIBWALLY, "Unable to derive BIP32 seed from BIP39 mnemonic");

	/* Copy first 32 bytes to our secret for comparison */
	memcpy(derived_secret.data, bip32_seed, sizeof(derived_secret.data));

	/* Compare the seeds */
	if (memcmp(derived_secret.data, file_secret.data, sizeof(file_secret.data)) != 0)
		errx(ERROR_KEYDERIV, "resulting hsm_secret did not match");

	printf("OK\n");
}

static void make_rune(const char *hsm_secret_path)
{