Operation
Each of the two random noise sources of the SwiftRNG LE is an analog electronic circuit that generates a random electrical signal from a reverse-biased Zener diode using the avalanche effect. The electrical noise generated by each source is independently amplified and converted into digital values as bytes. The bytes from both sources are combined to produce a low-bias random byte stream.
To further reduce bias, the resulting byte stream is processed by a conditioning component using SHA-256 or SHA-512 (Marsaglia’s XorShift64 is available with SwiftRNG LE device versions 1.2 and later).
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. The embedded monitoring logic notifies the host computer software if it detects an unexpected deviation from normal operation or a complete malfunction of either random source.
With SwiftRNG LE v1.2 and later and the latest software API updates, it is possible to retrieve frequency table snapshots for each of the noise sources to check the frequency distribution and quality of the random numbers.
In addition, the software kit continuously runs the Repetition Count and Adaptive Proportion tests (NIST SP 800-90B) on the host computer to verify the quality of the random bytes retrieved over USB.
The device is powered entirely by the USB bus, requires no additional power source, and 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 is ready to accept commands in less than a second (this time is used to run start-up tests and to wait for USB driver readiness).
Supported systems
- Linux (x86, x64, ARM)
- FreeBSD 12/13/14
- macOS (Intel and Apple Silicon)
- Windows 10/11 (64-bit) and Windows Server 2016/2019 (64-bit)
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 confirm that the electrical noise characteristics are within the expected ranges. The device does not require any tune-up after it is assembled, and the quality of the entropy produced remains constant. Before a device is shipped, random bytes produced by it are tested with well-known statistical tests for randomness (Diehard, Dieharder, NIST, and Ent), and the frequency tables for each device are inspected.
Device API
The SwiftRNG LE device API operates on 1-byte commands. The following table contains the complete command set with descriptions.
| Command as ASCII char | 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 16-bit integers that represent frequency tables of the noise sources + the status byte | The first 256 16-bit integers are frequency table of the first noise source and the next 256 16-bit integers 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 free or forced air circulation.
Other information
- Device version currently in production: SwiftRNG LE V1.6
- Weight: 21 grams (0.74 oz)
- Power consumption: no more than 140 mA in active mode and 70 mA when inactive
- Lead-free and RoHS compliance: all parts and materials used in SwiftRNG LE devices are lead-free and RoHS compliant
- Certified for FCC (Class B), ISED (Class B), and CE compliance. See the compliance page for details.
- Filled inside with an epoxy compound for protection and heat dissipation