If the idea of confidential information falling into the wrong hands scares the living daylights out of you, you'll definitely want to consider integrating some form of digital ID system into your enterprise email system.
A digital ID, which is also known as a digital certificate, is made up of two main components a digital signature and an encryption scheme. The digital signature is designed to verify that the message is really from the sender and that the message hasn't been altered while it traveled across the Internet. The encryption scheme is designed to scramble the message so as to make it unreadable with out the proper decryption tool.
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