/**
 * Compute HMAC-SHA256 of a balance value for a specific license key.
 * Uses LICENSE_SIGNING_KEY as the HMAC key (Ed25519 private seed, high-entropy).
 * Domain-separated with 'balance:' prefix to prevent cross-purpose HMAC confusion.
 */
export declare function signBalance(keyId: string, balanceCents: number): string;
/**
 * Verify that a balance record has not been tampered with.
 * Returns true if the HMAC matches, false if tampered.
 *
 * SECURITY: Since v1.2.24, ALL records are signed at startup (verifyBalanceIntegrity in index.ts).
 * A null/missing HMAC means the record was tampered with to remove the HMAC — fail fast.
 */
export declare function verifyBalance(keyId: string, balanceCents: number, storedHmac: string | null): boolean;
/**
 * Validate that a stripe_payment_intent_id follows a known format pattern.
 * Returns true if valid, false if the format is unknown.
 */
export declare function validatePaymentIntentId(paymentIntentId: string): boolean;
