信息安全的目标 (2)完整性(Integrity):Assurance that data received are exactly as sent by an authorized sender. 通过访问控制(access control))阻止篡改行为，通过消息摘要(message digest)算 法检验信息是否被篡改。信息安全的目标  （2）完整性（Integrity）：Assurance that data received are exactly as sent by an authorized sender. 通过访问控制(access control)阻止篡改行为，通过消息摘要(message digest)算 法检验信息是否被篡改