企業即時通信系統是即時通信技術在企業中的一種應用，面臨計算機病毒，身份識別、
數據機密性、真實性、完整性和不可否認性等安全問題。PKI是基于公鑰理論和技術的基礎安全平臺。本文設計了一種基于PKI的企業即時通信系統安全架構，并采用ECC公鑰密碼體制、IDEA對稱密碼體制和HASH-1消息摘要算法，給出基于該架構的EIM系統身份認證、數據加密、數字簽名等安全問題的解決方案。
關鍵字：企業即時通信系統；PKI；身份認證；數據加密；數字簽名
Abstract: Enterprise Instant Messenger(EIM) is an application of Instant Messenger on enterprise.It is facing many secure problems ,such as, computer virus, authentication，data secret, reality, integrity and undeniable ,and so on. PKI is a secure infrastructure based on public key theory and technology.This paper had designed a secure frame for Enterprise Instant Messenger based on PKI ,and had presented the solution of authentication,data encryption and digital signature based on the frame for EIM.
Key words：Enterprise Instant Messenger,PKI,Authentication,Data Encryption,
Digital Signature