/**
 * Result of a DKIM verification
 */
export interface IDkimVerificationResult {
    isValid: boolean;
    domain?: string;
    selector?: string;
    status?: string;
    details?: any;
    errorMessage?: string;
    signatureFields?: Record<string, string>;
}
/**
 * Enhanced DKIM verifier using smartmail capabilities
 */
export declare class DKIMVerifier {
    private verificationCache;
    private cacheTtl;
    constructor();
    /**
     * Verify DKIM signature for an email
     * @param emailData The raw email data
     * @param options Verification options
     * @returns Verification result
     */
    verify(emailData: string, options?: {
        useCache?: boolean;
        returnDetails?: boolean;
    }): Promise<IDkimVerificationResult>;
    /**
     * Fetch DKIM public key from DNS
     * @param domain The domain
     * @param selector The DKIM selector
     * @returns The DKIM public key or null if not found
     */
    private fetchDkimKey;
    /**
     * Clear the verification cache
     */
    clearCache(): void;
    /**
     * Get the size of the verification cache
     * @returns Number of cached items
     */
    getCacheSize(): number;
}