Unicorn is an open-source platform for digital trust, certificates, and electronic signatures. It combines certificate management, signature creation and validation, trust services, and secure communication within a modular architecture. The project supports established standards and technologies such as CMS/CAdES, PAdES, XAdES, OCSP, CRLs, Trust Service Lists, and PKCS#11. It serves as both a practical security solution and a platform for exploring modern PKI and digital trust infrastructures.
The project is written in Java and, so far, uses Bouncy Castle and the IAIK library for PKI, security, and the OCSP Responder. The trust lists are checked according to the rules of eIDAS, but there is no general guarantee that the checks are 100 % complete. This is because a further check against the ETSI / eIDAS reference project is required, which is also written in pure Java.
Other professionals who like to contribute to the project are welcome. This project aims to be a library for production use and to help people learn the principles of PKCS#11, PKI, X509 Certificates, CMS-Signatures, PaDEs, Trust List handling, and many other security topics.