export declare class Utils {
    static generateNumericId(): number;
    static getRandomString(size: number): string;
    static encryptSymmetric(plaintext: Uint8Array | string, key: string, iv: string): Promise<{
        ciphertext: Buffer;
        iv: string;
    }>;
    static decryptSymmetricBuffer(ciphertext: Buffer, iv: Buffer, key: Buffer): Promise<Buffer<ArrayBuffer>>;
    static decryptSymmetric(ciphertext: string, iv: string, key: string): Promise<string>;
    static genKey(): string;
    static genIv(): string;
    static genIvAsBuffer(): Uint8Array<ArrayBuffer>;
    static base64abc: string[];
    static base64codes: number[];
    static bytesToBase64(bytes: Uint8Array): string;
    static isBitOn(byte: number, index: number): boolean;
    static getBits(data: Uint8Array, bitOffset: number, numBits: number): number;
    static numAsOneByteUint(num: number): Uint8Array<ArrayBuffer>;
    static oneByteUint8AsNum(arr: Uint8Array): number;
}