Google Is Ending Gmail’s Third-Party “Send As”: What to Do Before 2027

Definition

S/MIME (Secure/Multipurpose Internet Mail Extensions) uses digital certificates to digitally sign and/or encrypt email.

It can provide:

• Sender authentication.
• Message integrity.
• Confidentiality.
• Cryptographic trust.
• Certificate-based identity.

XgenPlus describes its PKI architecture as using X.509 certificates, a Certificate Authority, S/MIME and AES-based encryption for secure business communication.

Example

A legal department sends a confidential contract to an external partner.

With appropriate S/MIME configuration:

1. The sender's identity can be cryptographically verified.
2. The message can be digitally signed.
3. The message can be encrypted for the intended recipient.
4. Tampering can be detected.

Practical application

Organizations should ask:

• Who issues email certificates?
• Who manages certificate renewal?
• How are certificates revoked?
• Who controls the Certificate Authority?
• Are encryption policies centrally administered?
• Can certificates follow employee lifecycle events?