SGeMS is a Home & Education software developed by SGeMS. After our trial and test, the software is proved to be official, secure and free. Here is the official description for SGeMS:

BSEditor: S-GeMS is a software for 3D geostatistical modeling. It implements many of the classical geostatistics algorithms, as well as new developments made at the SCRF lab, Stanford University.

S-GeMS relies on the Geostatistics Template Library (GsTL) to implement its geostatistical routines, including:
Kriging
Multi-variate kriging (co-kriging)
Sequential Gaussian simulation
Sequential indicator simulation
Multi-variate sequential Gaussian and indicator simulation
Multiple-point statistics simulation