Users who have to don a new monitoring device while they serve out their stay-home notice (SHN) need not fear that their actions will be snooped on, the authorities said yesterday.

The electronic wristbands, which alert the authorities should their wearers stray from their places of residence, do not store any personal data and cannot record any video or audio, said the Immigration and Checkpoints Authority (ICA), Ministry of Manpower (MOM) and Ministry of Education (MOE).

Any data transmitted is also protected by end-to-end certificate-based encryption.

"Only government officials authorised by the respective authorities will have access to the data for the purposes of monitoring and investigation," the authorities added.

Different devices are issued by ICA and MOM. ICA's device is also used by MOE for its students, while MOM's is for work pass holders and their dependants. Students on SHN residing in hostels at educational institutions are excluded as they would be under close observation.

For ICA's device, the protected data includes the personal details entered when users register their devices on an accompanying mobile app, StayHome@SG. The device, developed with the Home Team Science and Technology Agency (HTX), uses Bluetooth signals to determine if a person is within range of his home through the use of a "gateway device".

This gateway device, linked to the wristband, needs to be plugged into a wall power socket at the place of residence. It uses its own connection to ICA, and is not dependent on external networks. Neither the gateway nor wristband devices store any data. The devices work by sending an alert to the authorities if the distance between them gets too large.

The authorities get alerts if the wearer attempts to remove or tamper with the wristband, or switch off the gateway device. While the mobile app can use the global positioning system (GPS) to obtain the distance the wearer has strayed from his home, ICA cannot use the app or devices to track the exact location.

Meanwhile, the wearable devices issued by MOM use GPS technology instead of a linked gateway device. More details on this device were not available.

The authorities said public sector data protection rules will be followed strictly in managing and protecting personal data collected by these devices.

These include the recommendations of the Public Sector Data Security Review Committee, they added. Among other things, the review said the Government should collect only data that is necessary for its agency, and otherwise minimise the collection and retention period of data.

While the authorities did not say how long the data collected would be kept, ICA and HTX said their device will stop transmitting data once the SHN period ceases. The StayHome@SG app will also be locked from further use after that.