A system comprising a wearable therapeutic device is provided. The wearable therapeutic device includes:a memory；at least one cardiac sensing electrode to detect ECG signals of the patient；at least one treatment electrode configured to apply electrical current to the patient as defibrillation or pacing treatment；at least one processor coupled to the memory and the at least one cardiac sensing electrode and the at least one treatment electrode；a user interface component executed by the at least one processor and configured to receive an update session request and to generate an update session identifier responsive to receiving the request； anda system interface component executed by the at least one processor and configured to receive an encoded request including an encoded identifier of an update session and encoded device update information, to decode the encoded request to generate a decoded request including decoded device update information and a decoded identifier of the update session, to validate the decoded request by determining that the generated update session identifier matches the decoded identifier of the update session, and to apply the decoded device update information to the ambulatory medical treatment device.
