This approach makes use of programmability of embedded General Purpose Processors (GPP) for performing security operations. This approach reaches the demand in cost and flexibility but not in the power consumption and silicon area points of view. This approach sometimes leads to overwhelm the processing capacity of the embedded GPP. In the point of view of countermeasures against security attacks, this approach can provide several solutions. In [6], a countermeasure against side-channel attacks at software level is described