What is S/MIME?

What is S/MIME and how does it work?

S/MIME (Secure/Multipurpose Internet Mail Extensions) is the name of the protocol used to send signed and encrypted emails.

Only a Certification Authority (CA) can issue S/MIME certificates, following a series of verifications.

Why should you use S/MIME?

S/MIME certificates give you:

• security. Your emails that are signed and encrypted using S/MIME are protected from interception and tampering;
• message integrity. S/MIME guarantees that your messages have not been modified during transmission;
• authenticity of sender. A digital signature allows you to check the identity of the sender, to prevent phishing or fraud;
• versatility. As well as text, S/MIME also allows you to include multimedia content such as images, video and audio in your emails.

What types of S/MIME are there?

There are four types of S/MIME certificate: 

• Mailbox Validated (MV). Requires minimum verification of your details. This type is suitable if you need a quick and easy solution for signing and encrypting emails;
• Organization Validated (OV). Requires detailed verification of your organization. The certificate will show the details of your company, offering an additional level of trust and security;
• Individual Validated (IV). Useful for freelancers, to prove your identity in your emails; 
• Sponsor Validated (SV). For companies or public authorities who want to link emails to an individual. 

What does the S/MIME certificate issuing process involve?

Issuing S/MIME certificates involves:

1. requesting the certificate. Fill out the request form; 
2. identity verification. The CA verifies the personal details you have provided. For OV certificates, more detailed checks on the organization are required; 
3. issuing the certificate. Once verified, the S/MIME certificate will be issued and you can use it to sign and encrypt your emails.