/**
 * MD5 hash implementation used internally by PDF cryptography helpers.
 *
 * @private
 */
export declare class _MD5 {
    /**
     * Rotation amounts per round.
     *
     * @private
     */
    _r: Uint8Array;
    /**
     * K constants for MD5.
     *
     * @private
     */
    _k: Int32Array;
    /**
     * Compute the MD5 hash for the provided data slice.
     *
     * @private
     * @param {Uint8Array} data bytes.
     * @param {number} offset offset in `data`.
     * @param {number} length of bytes to hash.
     * @returns {Uint8Array} The 16-byte MD5 digest as `Uint8Array`.
     */
    hash(data: Uint8Array, offset?: number, length?: number): Uint8Array;
}