---
title: ENIntervalNumber
framework: exposurenotification
role: symbol
role_heading: Type Alias
path: exposurenotification/enintervalnumber
---

# ENIntervalNumber

A number assigned to each 10-minute window shared between all devices participating in the protocol.

## Declaration

```swift
typealias ENIntervalNumber = UInt32
```

## Discussion

Discussion These shared intervals of time derive from timestamps in UNIX Epoch Time. ENIntervalNumber(Timestamp) ← Timestamp / (60×10)

## See Also

### Exposure Criteria

- [transmissionRiskLevel](exposurenotification/entemporaryexposurekey/transmissionrisklevel.md)
- [rollingPeriod](exposurenotification/entemporaryexposurekey/rollingperiod.md)
- [keyData](exposurenotification/entemporaryexposurekey/keydata.md)
- [rollingStartNumber](exposurenotification/entemporaryexposurekey/rollingstartnumber.md)