针对Rao-Nam私钥密码体制修正案进行分析及改进.首先,考虑密文通过有扰信道时对修正案进行改进,提出加密与纠错相结合的加密纠错体制.其次,利用错误图样携带附加信息的方法提高了修正案的传信率.分析表明,新方案与修正案相比,在安全性、纠错能力、传信率、有扰信道的正确解密概率、长密钥问题等方面有很大提高. Aiming at the improvement of Rao-Nam private key cryptosystem, firstly, we consider the ciphertext to improve the amendment when there is a channel with scrambling, and put forward an encryption and error correction system combining encryption and error correction.Secondly, The additional information method improves the transmission rate of the amendment.The analysis shows that compared with the amendment, the new scheme has many advantages such as security, error correction capability, transmission rate, probability of correct decryption with scrambling channel, long key problem and so on Great improvement.