In accordance with one example, a method for comparing data units is disclosed comprising generating a first digest representing a first data unit stored in a first memory. A first encoded value is generated based, at least in part, on the first digest and a predetermined value. A second digest representing a second data unit stored in a second memory different from the first memory, is generated. A second encoded value is derived based, at least in part, on the second digest and the predetermined value. It is determined whether the first data unit and the second data unit are the same based, at least in part, on the first digest, the first predetermined value, the first encoded value, and the second digest, by first processor. If the second data unit is not the same as the first data unit, the first data unit is stored in the second memory.