Operation

Each of the two random noise sources of the SwiftRNG LE are analog electronic circuits that generate random electronic signals from reverse-biased Zener diodes using avalanche effect. The electrical noise generated by each random source is independently amplified and converted into digital values as bytes. The bytes produced are combined to produce a low bias random byte stream.

To further reduce bias, the resulting byte stream is processed by a conditioning component with conditioning functions such as SHA256 or SHA512 (Marsaglia’s XorShift64 is available when used with SwiftRNG LE device versions 1.2 and up).

The SwiftRNG LE implements an embedded health check test (HCT) that continuously monitors the quality of the random noise sources immediately after the electrical noise is digitized and before any further processing takes place.

When using SwiftRNG LE v1.2 and the latest software API updates, it is possible to retrieve frequency table snapshots for each of the noise sources for checking frequency distribution and quality of the random numbers.

The monitoring logic will check the quality of the final random bytes produced by continuously running ‘Repetition Count Test’ and ‘Adaptive Proportion Test’ tests. The embedded monitoring logic will notify the host computer software if it detects an unexpected deviation from normal operation or complete miss functioning of any of two random sources. This device is completely powered by a USB bus. It doesn’t require additional power source and it is protected by an overload protection circuit.

All SwiftRNG LE devices are equipped with ESD protection and EMI filtering circuits. After the device is plugged into a USB host, it becomes ready to accept commands in less the a second (this time is used to run start-up tests and waiting for USB driver readiness).

Supported systems

  • Linux (x86, x64) — Through the provided ‘swrandom’ kernel module, the random bytes generated by the SwiftRNG LE will be available for download from the device /dev/swrandom on x86-64 systems such as Ubuntu, Red Hat, CentOS 7, CentOS 6.6 and other Linux based x86-64 systems.

  • macOS 10.6 and up

  • Windows 7, 8.1, and 10 (x86, x64)

Fabrication and testing

All SwiftRNG LE devices are designed and assembled in the United States. After each device is assembled, both random noise sources are individually inspected and verified using an oscilloscope and a spectrum analyzer to test that the electrical noise characteristics are within expected ranges. The device does not require any tune-up after it is assembled and the quality of the entropy produced remains constant. Before it is shipped, random bytes produced by SwiftRNG LE are tested by running well known statistical tests for randomness such as: Diehard, Dieharder, NIST, and ENT and frequency tables for each device are inspected.

Device API

SwiftRNG LE device API operates based on 1 byte commands. The following table contains the complete command set and descriptions.

Command Response Description
x 16,000 random bytes + the status byte The response will contain 16,000 low biased (RAW) random bytes and an additional byte for the status byte. The status byte will contain 0 value for success or error code.
m 8 bytes of the device model + the status byte The response will contain 8 bytes for the device model as ASCII codes. The status byte will contain 0 value for success or error code.
v 4 bytes of the device version + the status byte The response will contain 4 bytes for the device version as ASCII codes. The status byte will contain 0 value for success or error code.
s 15 bytes of the device serial number + status byte The response will contain 15 bytes for the device serial number as ASCII codes. The status byte will contain 0 value for success or error code.
f 512 bytes that represent frequency tables of the noise sources + the status byte The first 256 bytes are frequency table of the first noise source and the next 256 bytes are frequency table of the second noise source. The status byte will contain 0 value for success or error code. This command is only available when used with SwiftRNG LE devices versions 1.2 or higher.
< 16,000 random bytes + the status byte The response will contain 16,000 of RAW unprocessed and unmodified random bytes generated from the first noise source. The status byte will contain 0 value for success or error code. This command is only available when used with SwiftRNG LE devices versions 1.2 or higher.
> 16,000 random bytes + the status byte The response will contain 16,000 of RAW unprocessed and unmodified random bytes generated from the second noise source. The status byte will contain 0 value for success or error code. This command is only available when used with SwiftRNG LE devices versions 1.2 or higher.

Operating temperature

  • Maximum device operating temperature: 149°F (65°C). The temperature is measured on the bottom surface of the device in the middle area.
  • Maximum ambient temperature: 106°F (41°C). The connected device should be located at least 1 inch away from other USB devices in an area with a free or forced air flow circulation.

Other information

  • Device versions currently in production: SwiftRNG LE v1.2
  • Weight: 21 grams (0.5 oz)
  • LeadFree/RoHS compliance: All parts and materials used in SwiftRNG LE devices are lead free and RoHS compliant
  • SwiftRNG LE draws no more than 110 mA (fixed power profile)
  • Filled inside with an epoxy compound for protection and heat dissipation