A browser cache-securing component facilitates online communication of confidential data, such as for financial information, purchasing transactions, or user identification. Caching webpages for subsequent presentation enhances user productivity and efficiency while reducing burdens on network resources. Yet, the security risks of intrusions into cache memory are mitigated by retaining encrypted data in cache memory without prior decryption. A modest overhead in decrypting when and if the webpage is to be presented again gains a security and privacy advantage without taking away functionality. Decrypted versions of confidential data can thereby be relegated to volatile memory. Upon termination of a session, a session key shared by a network server is deleted, preventing subsequent decryption. Executing the browser cache-securing component in a virtual machine environment allows multiple browser types to benefit from the security feature.