PLEASE be EXTRA careful with your wording of “untrusted”.
The words “Untrusted laptop” when referring to a corporate work laptop is horrible frame of thinking that is bound to cause problems with information ownership and employee and employer relationship.
All employee’s and employers maintain their systems of trust based on the personal and protected information that both the employee and employer’s may produce.
Yes an employee may have his own private information i.e. personal Health Records or performance reviews on a company owned device.
Any small or big corporation is within their rights to define their own personal IT ownership and information policies.
I’d recommend you at least talk with your IT department and have a conversation according your companies policies and procedures when deciding what information is owned by you or your employer.
i.e. don’t encrypt your employers information by accident and then not realize you are syncing to a location not approved by your employer.