---
name: "urng"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/urng"
---

# urng(4)

USB Random Number Generator devices

## NAME

**urng** – USB Random Number Generator devices

## SYNOPSIS

**urng\* at uhub?**

## DESCRIPTION

The **urng** driver provides support for various true random number generator (TRNG) devices connected via USB. **urng** reads raw entropy from the device at a (hardware dependent) interval and stirs it into the system entropy pool with enqueue\_randomness(9).

## HARDWARE

The following devices are supported by this driver:

- Araneus Alea I and II

  Capable of delivering 100kbit/sec of hardware-generated entropy.

- Altus Metrum ChaosKey 1.0

  This device is capable of providing entropy at 10Mbit/s.

## SEE ALSO

[intro(4)](/intro/4.md), [usb(4)](/usb/4.md), enqueue\_randomness(9)

## HISTORY

The **urng** driver first appeared in OpenBSD 6.2.

## AUTHORS

The **urng** driver was written by Aaron Bieber ⟨*abieber@openbsd.org*⟩, Jasper Lievisse Adriaanse ⟨*jasper@openbsd.org*⟩, and Sean Levy ⟨*attila@stalphonsos.com*⟩.