This means that they cannot completely filter or control what is being carried via electronic mail messages or inside downloaded programs. There are some tools that can provide the most rudimentary filtering to try to catch viruses, worms and e-mail bombs, but it is impossible to completely protect against these attacks with just a connectivity container. The eavesdropper will only see the encrypted data and therefore cannot capture usernames and passwords, thereby also preventing that type of intrusion attack. It is also possible to stop password eavesdropping by using authentication via digital tokens or one-time passwords. The strongest level of protection is created by encrypting all data sent from the user's system and decrypting it at the destination.
Encryption also protects the user from the intruder making changes to information being sent.
For example, if the user is sending payment information to a mail order house an intruder could modify the data to transfer the funds to their account rather than the account originally specified. Many companies are now implementing telecommuting and are becoming geographically dispersed. In order to have secure communications, these companies currently must use costly leased-lines. This technology allows users who are at different locations to communicate as though they are directly connected to each other while using the much less expensive public Internet to carry the data. This container is colloquially call the sandbox.