/**
 * A utility class for encoding and decoding Base64 strings.
 */
export declare abstract class Base64 {
    abstract prop: string;
    /**
     * Converts a string between different encodings (base64, utf-8).
     *
     * @private
     * @param value - The string value to encode or decode.
     * @param from - The current encoding type: 'utf-8' or 'base64'.
     * @param to - The target encoding type: 'utf-8' or 'base64'.
     * @returns - The encoded or decoded string in the target format.
     */
    private static generate;
    /**
     * Encodes a string from UTF-8 to Base64.
     *
     * @param value - The string to encode in base64 format.
     * @returns - The Base64-encoded string.
     *
     * @example
     * const encoded = Base64.encode('Hello World');
     * console.log(encoded); // Outputs: "SGVsbG8gV29ybGQ="
     */
    static encode: (value: string) => string;
    /**
     * Decodes a Base64-encoded string to UTF-8.
     *
     * @param value - The Base64-encoded string to decode.
     * @returns - The decoded string in UTF-8 format.
     *
     * @example
     * const decoded = Base64.decode('SGVsbG8gV29ybGQ=');
     * console.log(decoded); // Outputs: "Hello World"
     */
    static decode: (value: string) => string;
}