/**
 * Stringifies the imgproxy modifier for use within the
 * imgproxy URL.
 *
 * @param opCode  The operation key
 * @param values  The values
 * @returns       The stringified modifier
 */
declare const stringifyOptions: (opCode: string, values: Array<string | number | boolean | undefined>) => string;
/**
 * Encodes the filepath to base64url.
 *
 * @param filePath  The file path
 * @returns         The base64url encoded file path
 */
declare const encodeFilePath: (filePath: string) => string;
/**
 * Generates the URL signature for the specified imgproxy param string.
 *
 * See https://github.com/imgproxy/imgproxy/blob/947d65cf29fe26e5e4d38ca8a17e44c7402e437c/docs/configuration.md#url-signature
 *
 * @param paramString  The param string
 * @param key          The hex-encoded key
 * @param salt         The hex-encoded salt
 * @param length       The number of bytes to use for the signature before encoding to Base64
 * @returns            The base64url encoded signature
 */
declare const generateSignature: (paramString: string, key: string, salt: string, length: number) => string;
export { stringifyOptions, encodeFilePath, generateSignature };