SMIMEcertificaten

SMIMEcertificaten, also known as S/MIME certificates, are digital certificates used to sign and encrypt email messages according to the S/MIME standard. They bind a sender's or organization's identity to a public key, providing authentication, data integrity, non-repudiation, and confidentiality.

Typically issued by a trusted Certification Authority after identity verification; based on X.509 v3; include subject, issuer, validity period, public key, and extensions such as keyUsage and extendedKeyUsage (emailProtection).

Use: signing ensures authenticity; encryption ensures confidentiality; recipients must have the corresponding certificate; mail clients use the public key for encryption and verify signatures with the sender's public key; trust is established via CA trust anchors installed in the client.

PKI and revocation: relies on CA hierarchy; revocation via CRLs or OCSP; certificates expire and require renewal; private keys should be protected by passwords or hardware tokens.

Interoperability and comparison: S/MIME is widely supported (Outlook, Apple Mail, Thunderbird); contrasts with PGP, which uses a decentralized Web of Trust rather than centralized CA.

Regulatory and deployment notes: in some jurisdictions, qualified S/MIME certificates under eIDAS carry higher legal status; common in enterprises and government organizations for email security.

Challenges: certificate management, key loss, interoperability pitfalls, user education.