When the first e-mail services were planned, encryption was not a top priority. E-mail is used to share messages for people who don’t know each other. Online networking is wide open to all forms of threats, and we’re not really pretending to be thorough here. This is especially true of Internet-based MHSs working in the hostile atmosphere of the Internet. It is popular in network security literature to differentiate between passive and active attacks. We quickly expand on potential ways to indirectly or aggressively target Internet-based e-mail services. In a passive attack, the adversary read (but did not write) access to the data being transmitted. If the information is available and visible to the enemy, so one is talking about a passive wiretapping or eavesdropping attack. In this case, the adversary is in a position to extract and interpret the information stored in the records. If the data is encrypted, it will not be open and directly available to him or her.
The Unsecure Email