A digital signature is a mathematical technique used to validate the authenticity and integrity of a message, software or digital document. It's the digital equivalent of a handwritten signature or stamped seal, but it offers far more inherent security. A digital signature is intended to solve the problem of tampering and impersonation in digital communications.
The Matrix42 AG uses this technique to ensure the authenticity and integrity of Extensions. Whenever an author uploads an Extension to the Matrix42 DevOps Portal he/she will need to make sure that this Extension is digitally signed using a Matrix42 Developer Identity.
Since this security feature will be enforced from the first of September 2021 all Extensions published prior are not digitally signed. You can see if an Extension is digitally signed by the blue shield which is shown in the Matrix42 Extension Gallery:
The blue shield shows if an Extension is digitally signed by a Matrix42 Developer Identity.