Abstract: With the development of information technology as well as the in-depth implementation of e-government,  a lot of safety questions are resulted. RSA encryption technique is an important technique used in the transfering safely information. Based on RSA public-key code methods,  this paper proposes an encryption algorithm of electronic official documents. In this algorithm, a weak key of the RSA cryptosystem is found. It turns out that the modulus of the RSA cryptosystem is easy to factor if the the ratio of the two prime factors of the modulus can be well approximated by a small fraction.

Key words: electronic official documents, encryption, safety, RSA public-key code

摘要： 随着信息技术的发展以及电子政务的深入实施，带来一系列电子公文安全性问题。RSA加密技术是一种用于信息安全传输的重要技术。提出了一种改进的RSA公钥密码算法，并应用于电子公文加密。在该算法中，找到RSA公钥密码算法的一类弱密钥，指出如果RSA数的两个素因子的比值能够被一个小分数有效逼近，则RSA数是容易分解的。

关键词: 电子公文, 加密, 安全性, RSA（Receive, Shamir, Adleman）公钥密码