How define technician id by Key API ?

How define technician id by Key API ?

Hello!

How define technician id by Key API ?
For example: 
1. User has Key for get API request from SDesk without  login&password auth. 
2. He wants to get all his own "open" Orders without login&password auth.
Is there any methods  identify UserID or technicianID by API key and get his orders by json?

Thanks!

                  New to ADSelfService Plus?