中文摘要：

针对目前加密工具存在加密算法单一、密钥管理不方便、密文文件共享不安全、文件重要性未区分等问题,设计了一个支持多种安全级别的文件加密工具。该工具的密钥随机生成,按用户分组组织,保存于密钥文件中,并按照文件的重要性,把它分成一般、中等和高3个安全级别。一般和中等安全级别文件加解密时,自动从密钥文件中查找密钥,而后者解密时需要进行用户认证,高安全级别文件的密钥不在密钥文件中,加密时随机生成,用投票者的公钥加密后保存到服务器,解密时需要所有投票者同意才能解密。该工具加密时随机选择加密算法,密钥无需用户记忆,通过密钥管理保证不同级别密文文件共享的安全,既具有操作的方便性,又具有较高的安全性。

英文摘要：

In order to solve the problem of existed encryption tool that it only supports one kind ofencryption algorithm, key management is not convenient, encrypted file sharing is unsafe, and the importance of file is not distinguished, multiple security level supported file encryption tool is designed. The keys are generated randomly and saved in the key file, which are grouped by users. According to the importance of files, general security level, medium security level and high security level are distinguished. When the general or medium security level file is encrypted or decrypted, the key is automatically found from the key file, and the latter needs user authentication when decrypted. The key of high security level file is not in the key file, which is generated randomly, and is saved to the server after being encrypted with voters＇ public key. And the encrypted file can be decrypted after all voters agreed. The encryption algorithm is selected randomly and the key is input automatically when encryption, the security of file sharing is ensured by key management. The tool not only has the convenience of operation, but also has high security.