Charity Engine® is based on Berkeley University's BOINC software, as used by dozens of famous 'citizen science' projects such as SETI@home, IBM's World Community Grid and the BBC's climateprediction.net.
BOINC has been safely downloaded over ten million times and over a million PCs are running it right now. Since its first release in 2002, BOINC has never had a single security breach and is literally safer than surfing the web.
Charity Engine’s BOINC app is also deliberately set for low energy use and typically consumes less power than charging two mobile phones.