This book includes about concept of cerified email.there are three approaches online ,Inline,and offline TTP.In this book, three protocols for secure e-mail that protects both the sender and the receiver, and can be implemented using current e- mail products and existing Internet infrastructure is proposed.First an optimistic approach is applied, that make use of a trusted third party(TTP) but in an optimistic way,TTP is involved only in case of dispute, which is expected to be a rare event. Second, Inline protocols which employ a trusted third party (TTP), which acts as a delivery channel. Both parties send their items to the TTP which checks for their integrity, ensures the validity and fairness of the exchange, and forwards the items to the intended receivers.Third, online protocol, similar to inline protocol, but sender can communicate to receiver directly. After that, TTP manages all extra effort to provide the Integrity, validity, and fairness of the exchange, and forwards the message to receiver. TTP also sends to sender, a receipt of proof that receiver is accepted that message.