Guaranteeing the integrity of data by using a digital signature - [instrumentationnotes]

There are many data-logging applications in which measuring a signal and storing the measured values are not sufficient. Sometimes you must be able to prove that the record that you have made, and that you make use of later, has not undergone any changes since the time at which the measurement was made. This is the case in many forensic applications. Courts are very leery of admitting electronic recordings of conversations into evidence because it is so easy to make undetectable changes to digital recordings.