The MES Solutions designed for the food, beverage and the pharmaceutical industries need to cover few extra requirements to be used along with eBRS systems. These requirements are mainly driven by regulatory requirements about how process data should be stored and protected to be able to be used as part of batch records.

The US FDA’s CFR 21 Part 11 has become the baseline requirement for MES system used in these industry even outside the US.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=11

An important section of this regulation is the requirement for linking records and signatures :

Electronic signatures and handwritten signatures executed to electronic records shall be linked to their respective electronic records to ensure that the signatures cannot be excised, copied, or otherwise transferred to falsify an electronic record by ordinary means  

MES Systems generally use Encryption Algorithms for Digital Signatures to satisfy this requirement. This means anyone who does not have the ‘Private’ key, will not be able to forge the signature and it is assumed that having access to the Primary Key is not considered ‘ordinary’.

While not explicitly said, using Database level security is not usually considered enough protection against ordinary tempering of the signature and that is mostly because of the preventable but prevalent loose security in DB level in industries.

Engineers frequently ask for and successfully acquire higher access rights that they needed for commissioning, maintenance and debugging systems. By having the access rights to add/update/delete records,  a user can easily clone signature data if they are not digitally signed.