A signature is a secure electronic signature if, through the application of a security procedure, it can be demonstrated that the electronic signature at the time the signature was made was all of the following:
1. Unique to the person using it.
2. Capable of verification.
3. Under the sole control of the person using it.
4. Linked to the electronic record to which it relates in such a manner that if the record were changed the electronic signature would be invalidated.