GreenShield Mail is software for the end-to-end encryption and signing of emails. It is realized as an add-in for Microsoft Outlook and IBM/HCL Notes. The user-interface is seamlessly integrated into the respective email client. Since encryption and signing are performed automatically, user interaction is kept to a minimum, which increases convenience and thus user acceptance. Flexible group policies allow for central administration and easy pre-configuration.

GreenShield Mail provides asymmetric encryption based on the S/MIME standard and is interoperable with other S/MIME compliant applications. It uses X.509 certificates and supports a large variety of smart cards on which the corresponding long-term secrets, such as the secret signature or encryption keys, are stored.

Revocation checks are performed via OCSP or revocation lists that can be retrieved via LDAP or HTTP. Extensions for the connection to (automatic) certificate management systems are available.

Compared to the built-in mail encryption functions of Outlook and Notes, GreenShield Mail provides a higher security level, as it features encapsulated crypto functions and advanced smart card support.

The German Federal Office for Information Security (BSI) has approved GreenShield Mail for the transmission and processing of classified information up to classification level VS-NfD/NATO restricted/EU restricted.

GreenShield is also available as GreenShield File for the end-to-end encryption and signing of files. Taken together, both products form a seamless solution for email and file security.