The ODISSEI Secure Supercomputer (OSSC) is a high performance computing (HPC) facility with strict security measures for processing sensitive data. The platform facilitates researchers to perform large-scale analyses of highly-sensitive data – such as CBS Microdata – in SURF’s HPC environment. The OSSC platform is based on customisable virtualized private clusters that are deployed on the existing Supercomputer Cartesius. The OSSC can also be considered as an enclave of Statistics Netherlands within the domain of SURF. Thus, the OSSC platform meets the highly-strict requirements of The Statistics Netherlands in legal, technical and security aspects.