Disclosed is a method of validating the contents of a real-time clock in a digital circuit. A plurality of memory elements create a first random signature value when power is newly applied to a circuit. The plurality of memory elements maintain the first random signature value while power to the circuit is maintained. The first random signature value is stored as a reference value such that the reference value is not altered by a power interruption. When power to the circuit is lost and then regained, a second random signature value is created. The second random signature value likely will no longer match the reference value because both the reference value and the second signature are random. When the reference value does not match the signature value, the real-time clock value is considered invalid. User input may be employed to correct the real-time clock value.