UTC Time Calibration QR Tool
Published 2026-09-09
中ENGenerate a signed time QR code based on the UTC timezone for devices to scan and calibrate their clock; auto-refreshes every second, no installation needed.
The UTC time-calibration QR tool targets devices that sync their clock to UTC: the device scans the QR code, parses the signed UTC time it carries, verifies the signature, then updates its local clock.
Step 1: Generate
1. Open the tool (Technical Docs → Online Tools → UTC Time Calibration QR Tool);
2. Enter the signing password agreed with the device side (the default matches the factory convention — change it and sync to devices as needed);
3. Scan the QR code with the device; after signature verification, the device calibrates its clock to the encoded time;
4. The QR code refreshes every second, so the time is always the UTC time at the moment of generation.
Payload Format
The payload consists of a protocol header + UTC system time + HMAC-MD5 signature:
___VBAR_CONFIG_V1.1.0___{systemtime='YYYY-MM-DD HH:mm:ss'}--<Base64(HMAC-MD5)>
The time field is built from UTC getters (getUTC*), exactly matching the string format of the local-time tool.
Security Notes
The key participates in HMAC-MD5 signing and the device verifies with the same key; everything runs locally in your browser and no data is uploaded.
FAQ
What is the difference between UTC and local time calibration?
This tool builds the time payload from the UTC timezone, so the result is independent of the device's local timezone — ideal for devices that sync to UTC.
What is the signing password?
The password you enter when generating; it signs the payload with HMAC-MD5 and the device must verify with the same key.
Does the QR code leak system information?
It only contains the protocol header, the current UTC time and the signature — no network or account information.