A method and an apparatus for preserving confidentiality of an electronic mail are disclosed. One embodiment of the present invention, or an electronic mail confidentiality preserver of an email client, includes an input-processing engine and an encryption/decryption engine that is coupled to the input-processing engine. Based on a confidentiality level, the input-processing engine mainly limits abilities of a user of the email client to manipulate an electronic mail received by the email client. On the other hand, the encryption/decryption engine mainly limits the user's access to a local storage if the user's access involves an electronic mail.