/**
 * Crypto utilities for webhook signature verification
 */
export declare class CryptoUtils {
    /**
     * Create HMAC SHA256 signature
     */
    static createHmacSha256(data: string, secret: string): Promise<string>;
    /**
     * Verify HMAC SHA256 signature
     */
    static verifyHmacSha256(data: string, signature: string, secret: string): Promise<boolean>;
    /**
     * Constant time string comparison to prevent timing attacks
     */
    static constantTimeCompare(a: string, b: string): boolean;
}
//# sourceMappingURL=crypto.utils.d.ts.map