If you thought that clicking that “delete” button will just delete your mail totally, then you couldn’t be more wrong. By using the “delete” button, an e-mail is rendered invisible to that particular user. It is instantly lined up to be overwritten. The fact is though, until it is indeed overwritten, it exists. Its existence may span for a longer time on enterprise servers. Hence, even if it’s removed from your computer, it still exists on the company’s host server. Traces of the deleted mail are ever present waiting to be retrieved when required.
Companies that offer e-mail hosting services are obliged legally to submit user information to concerned law enforcement agencies. Deletion of an e-mail being an uncertainty implies that any information that you may compose will remain accessible forever. You can be rest assured that total deletion of anything is impossible.
Anonymous tools of communication are not perfect in the current world. Even intelligence big-wigs like the US commander in Afghanistan and the director of USA’s CIA have proven to be vulnerable. Rigorous security protocols and some care may have prevented such unwanted intrusions into their privacy. You can always make your mails more complex to access, but this may also render it more complicated to use.
Anonymous web-mail accounts combined with necessary encryption makes your IP address almost impossible to clock. Secure browsers such as tor and circumvention tools also come in handy. Hence, you may evade the overzealous authorities. However, your e-mail service provider might retain copies of mails sent by you. That and some contextual information to go with may be enough to nab you. Hushmail, which gives you guarantees downright that not even their own employees can compromise your anonymity has been known to bend to the will of law and turned over user information in the past. The government mandates that ISP’s keep digital records of specific periods in time.
Regardless of the e-mail setup you utilize, always make use of secure deletion software like Eraser that may be able to delete the particular file completely. The real issue though is that even though you may wipe out the presence of the e-mail even on the company server, there still exist traces that suggest a prior presence of such an e-mail on the server. Secure deletion may sometimes also leave the name of the deleted file exist on the computer. Big web-mail providers akin to yahoo, Google and Microsoft preserve and release the ID that a particular user has used to login.
In addition, any contact made with that particular e-mail by the computer with a visible IP can be used to unravel whole conversations. Of course, this all a moot point if you decide to divulge you account information. The message is right in there, but someone has to go and make the all important discovery.
Fact remains that e-mail security is nothing but a popular myth. Large corporations follow every single one of the prescribed practices. Otherwise maintain security of its employees is exceedingly impossible. There will always be breaches.