S/MIME
S/MIME, or Secure/Multipurpose Internet Mail Extensions, is a protocol used for securing email communication by providing encryption, digital signing, and authentication capabilities. S/MIME is based on the MIME (Multipurpose Internet Mail Extensions) standard and extends it to support cryptographic operations using digital certificates. With S/MIME, users can encrypt email messages to ensure confidentiality, digitally sign messages to verify the sender's identity and message integrity, and authenticate recipients to prevent spoofing and phishing attacks. S/MIME relies on X.509 digital certificates issued by trusted certificate authorities (CAs) to establish trust between communication parties and enable cryptographic operations. S/MIME is widely supported by email clients and servers, making it a popular choice for securing email communication in both personal and enterprise environments. s://en.wikipedia.org/wiki/S/MIME