A Group File Encryption Method using Dynamic System Environment Key

File encryption is an effective way for an enterprise to prevent its data from being lost. However, the data may still be deliberately or inadvertently leaked out by the insiders or customers. When the sensitive data are leaked, it often results in huge monetary damages and credit loss. In this paper, we propose a novel group file encryption/decryption method, named the Group File Encryption Method using Dynamic System Environment Key (GEMS for short), which provides users with auto crypt, authentication, authorization, and auditing security schemes by utilizing a group key and a system environment key. In the GEMS, the important parameters are hidden and stored in different devices to avoid them from being cracked easily. Besides, it can resist known-key and eavesdropping attacks to achieve a very high security level, which is practically useful in securing an enterprise´s and a government´s private data.