A secured delivery system can include a doorbell device comprising a scanner, and a locking mechanism operatively connected to the scanner, a computer processor or a cloud server and a structure, such as a residence or lockbox. A key, which can be in the form of a bar code, can be generated and sent to delivery or service personnel needing access to the structure. The delivery or service personnel present the bar code to the scanner. Upon reading the bar code, the locking mechanism is unlocked thereby allowing access to the structure.