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Secure/Multipurpose Internet Mail Extension (S/MIME)

What is S/MIME?

Secure/Multipurpose Internet Mail Extension (S/MIME) is an email encryption and signing industry standard widely used by corporations to enhance email security. S/MIME is compatible with most enterprise email clients.

In simple terms, S/MIME encrypts and digitally signs emails to ensure that the email is authenticated and its contents have not been altered in any way.

How does S/MIME work?

S/MIME works based on asymmetric encryption. This means that there is a set of keys involved to encrypt and decrypt an email.

An S/MIME certificate is installed on the email clients of both the recipient and the sender. When an email is sent, the sender encrypts the email using the recipient's public key and the recipient decrypts the email using the private key. S/MIME also attaches a digital signature to an email. This ensures that the sender is authorized to send emails from a certain domain.