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 4 types of S/MIME: 

• Mailbox Validated (MV). Requires minimal verification of your information. It certifies that the sender (whoever they may be) has control over a specific mailbox. This is suitable if you need a quick and simple solution for signing and encrypting emails;
• Organization Validated (OV). Requires detailed verification of your organization. The certificate will display your company’s information, offering an additional level of trust and security. It certifies that the sender, in addition to having control over a specific mailbox, is a particular legal entity;
• Individual Validated (IV). Certifies that the sender, in addition to having control over a specific mailbox, is a particular individual. For this reason, it requires identification of the certificate holder through biometric or alternative recognition. Useful if you are a freelancer and want to prove your identity in emails; 
• Sponsor Validated (SV). Certifies that the sender, in addition to having control over a specific mailbox, is a particular individual associated with a specific legal entity. For this reason, it requires identification of the certificate holder through biometric or alternative recognition. Suitable if you are a company or a public administration and want to associate a specific individual with your emails. 

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.