用椭圆曲线实现ElGamal算法，根据来源于国密局SM2算法的标准参数，Fp-192曲线，运用一个大数类能够实现密码算法所需要的基本运算。-Using elliptic curve ElGamal algorithm, according to secret from the State Bureau of SM2 algorithm standard parameters, Fp-192 curve, the use of a class of large numbers cryptograp