Privacy-Enhancement Mail

What is a Privacy Enhanced Mail (PEM)?

PEM is an email security standard that enables safe electronic mail communication via the internet. Email message security has been incredibly critical in recent years. The internet architecture board has adopted it to address security concerns with emails.

How Does PEM Work?

Privacy-Enhanced Mail works in four steps:

1. Canonical Conversion
The email message travels in a uniform and independent format, regardless of the operating system and architecture of the sender and the receiver, thanks to privacy-enhanced mail, which transforms the email into an abstract, canonical representation.

2. Digital Signature
A digital signature for email communications is created in this stage. First, the message digest of an email message is constructed using the MD, MD2, or MD5 algorithms. The sender's private key is then used to encrypt this message's digest in order to verify the sender's digital signature.

3. Encryption
In this step, a symmetric key is used to encrypt both the original email message and the digital signature made in step 2. The DES or DES-3 algorithm is used for encryption.

4. Base-64 Encoding
This is the last step in privacy-enhanced mail. The Base-64 Encoding process converts any binary input into the printable character output. 
 

Where Can I Get PEM? 

There are at least two different implementations of PEM available, including Riordan's Internet Privacy Enhanced Mail (RIPEM), written by Mark Riordan, and the second implementation, which is called TIS/PEM (version 7.0), written by Trusted Information Systems, Inc.

What Can I Use PEM with?

Almost any program capable of producing Internet mail can be used with PEM, as long as the other person is also using PEM (depending on the implementation you decide to use).