Enhancement of Email Security Services

The aim of this book is to improve the E-mail security service. In addition, many related researches have been reviewed, and security issues have been discussed with the main known E-mail protocols. Also, a new improved protocol based on the Public key is proposed. The proposed system is a hybrid cryptosystem that uses public keys to transfer the secret key (Ks) and the symmetric cryptosystem keys to ensure the system confidentiality and integrity