Operational system checks must be performed regularly. Access to the database search software must be limited. The type of security required also depends on the type of system being used and whether that system is open or closed. In addition, electronic and handwritten signatures executed to electronic records must be linked to their respective records so that signatures cannot be excised, copied or otherwise transferred to falsify an electronic record by ordinary means. Because of these security concerns, electronic signatures must be unique.
Unique signatures comprise more than just different usernames and passwords.
The reuse or reassignment of electronic signatures to someone other than the original user must also be taken into consideration. In a forensic laboratory, for instance, officers may be assigned electronic signatures based on their badge numbers rather than their names. If an officer retires or a badge number is reassigned, the previous owner must not be confused with the current owner. The same criteria apply to any other laboratory. Because electronic signatures can often be guessed easily, FDA included requirements to guard against this occurrence.