import type { DKIMConfig } from "./types.js";
/** Result of DKIM signing — the header line to prepend. */
export interface DKIMSignResult {
    /** Complete DKIM-Signature header line (without trailing CRLF). */
    header: string;
}
/**
 * Canonicalize headers using the relaxed algorithm (RFC 6376 §3.4.2).
 */
export declare function canonicalizeHeadersRelaxed(headers: string, fieldNames: string[]): string;
/**
 * Canonicalize body using the relaxed algorithm (RFC 6376 §3.4.4).
 */
export declare function canonicalizeBodyRelaxed(body: string): string;
/**
 * Import a PEM-encoded private key into a Web Crypto CryptoKey.
 */
export declare function importPrivateKey(pem: string, algorithm: "rsa-sha256" | "ed25519-sha256"): Promise<CryptoKey>;
/**
 * Sign a raw MIME message with DKIM.
 */
export declare function signDKIM(rawMessage: Uint8Array, config: DKIMConfig): Promise<DKIMSignResult>;