/**
 * Options for cryptographic operations
 */
export interface SigningOptions {
    /**
     * Algorithm to use for signing
     * @default 'HMAC'
     */
    algorithm?: 'HMAC' | 'RSA';
    /**
     * Output encoding format
     * @default 'hex'
     */
    encoding?: 'hex' | 'base64';
    /**
     * Hash algorithm for HMAC
     * @default 'SHA-256'
     */
    hash?: 'SHA-256' | 'SHA-384' | 'SHA-512';
}
/**
 * Key validation options
 */
export interface KeyValidationOptions {
    /**
     * Minimum key length in characters
     * @default 32
     */
    minLength?: number;
    /**
     * Minimum entropy (unique characters)
     * @default 8
     */
    minEntropy?: number;
    /**
     * Check for weak patterns
     * @default true
     */
    checkWeakPatterns?: boolean;
}
/**
 * Create an HMAC key from a secret string
 *
 * @param secret The secret key string
 * @param options Validation options
 * @returns A CryptoKey for HMAC operations
 * @throws Error if the secret doesn't meet security requirements
 *
 * @example
 * ```typescript
 * const key = await createHmacKey('your-secret-key-at-least-32-chars');
 * ```
 */
export declare function createHmacKey(secret: string, options?: KeyValidationOptions): Promise<CryptoKey>;
/**
 * Sign data using HMAC or RSA
 *
 * @param key The CryptoKey to use for signing
 * @param data The data to sign
 * @param options Signing options
 * @returns The signature as a hex or base64 string
 *
 * @example
 * ```typescript
 * const signature = await signData(key, 'data-to-sign');
 * ```
 */
export declare function signData(key: CryptoKey, data: string, options?: SigningOptions): Promise<string>;
/**
 * Verify a signature using HMAC or RSA
 *
 * @param key The CryptoKey to use for verification
 * @param signature The signature to verify
 * @param data The original data that was signed
 * @param options Signing options (must match those used for signing)
 * @returns True if the signature is valid, false otherwise
 *
 * @example
 * ```typescript
 * const isValid = await verifySignature(key, signature, 'data-to-sign');
 * ```
 */
export declare function verifySignature(key: CryptoKey, signature: string, data: string, options?: SigningOptions): Promise<boolean>;
/**
 * Convert an ArrayBuffer to a hexadecimal string
 *
 * @param buffer The buffer to convert
 * @returns Hex string representation
 */
export declare function toHex(buffer: ArrayBuffer): string;
/**
 * Convert a hexadecimal string to an ArrayBuffer
 *
 * @param hex The hex string to convert
 * @returns ArrayBuffer representation
 * @throws Error if the hex string is invalid
 */
export declare function fromHex(hex: string): ArrayBuffer;
/**
 * Convert an ArrayBuffer to base64
 *
 * @param buffer The buffer to convert
 * @returns Base64 string
 */
export declare function bufferToBase64(buffer: ArrayBuffer): string;
/**
 * Convert a base64 string to ArrayBuffer
 *
 * @param base64 The base64 string to convert
 * @returns ArrayBuffer
 */
export declare function base64ToBuffer(base64: string): ArrayBuffer;
/**
 * Constant-time string comparison to prevent timing attacks
 *
 * @param a First string
 * @param b Second string
 * @returns True if strings are equal
 */
export declare function constantTimeCompare(a: string, b: string): boolean;
/**
 * Generate a cryptographically secure random string
 *
 * @param length The length of the string to generate
 * @param charset The character set to use
 * @returns Random string
 */
export declare function generateSecureRandomString(length: number, charset?: string): string;
/**
 * Hash data using SHA-256 or other algorithms
 *
 * @param data The data to hash
 * @param algorithm The hash algorithm to use
 * @returns Hex-encoded hash
 */
export declare function hashData(data: string, algorithm?: 'SHA-256' | 'SHA-384' | 'SHA-512'): Promise<string>;
/**
 * Create a time-based signature with expiration
 *
 * @param key The signing key
 * @param data The data to sign
 * @param expiresIn Expiration time in seconds
 * @returns Signature with timestamp
 */
export declare function createTimedSignature(key: CryptoKey, data: string, expiresIn?: number): Promise<{
    signature: string;
    expires: number;
}>;
/**
 * Verify a time-based signature
 *
 * @param key The signing key
 * @param signature The signature to verify
 * @param data The original data
 * @param expires The expiration timestamp
 * @returns True if valid and not expired
 */
export declare function verifyTimedSignature(key: CryptoKey, signature: string, data: string, expires: number): Promise<boolean>;