What is the Denylist?
The denylist is a list of IoT Hotspot public keys and a cryptographic signature that have been identified not to be accurately contributing to network coverage or are otherwise circumventing the good faith of the network in an attempt to earn rewards. Rewards gaming by dishonest actors, even as a small percentage of the network, erodes network integrity.
Examples include, but are not limited to: cluster packet forwarders, misasserted locations, misasserted antennas, multiple or shared antennas, attenuators, amplifiers, and Data Credit farming.
The denylist is another tool in a broader range of tools to incentivize Hotspots on the network to provide the most honest and accurate wireless coverage possible.
The denylist is sourced from the community to keep the network decentralized. Credible decentralization ensures that no one entity can control the network. Any coordinated effort to game rewards, block data transfer, or censor information to benefit one party while harming another, undermines the mission of creating global, open wireless networks.
Network Impact
Hotspot Owners: For any well-asserted, appropriately compensated Hotspot, the denylist only benefits you. By denying token distribution to dishonest Hotspots, those tokens are shared amongst honest Hotspots.
Bad Actors: If your Hotspots are earning tokens without providing coverage, they are likely to appear on the Denylist and will stop earning token Rewards.
How Denylisting is Determined
Denylist detection criteria is based on classifiers which have the following properties:
- A classifier produces an 0-1 output as to the confidence of a Hotspot providing proper coverage according to the classifier algorithm
- A (growing) number of classifiers are used to produce a scorecard for a Hotspot on the deny list where each classifier score is weighted to produce the final score. This scorecard is tied to the deny list version the Hotspot is on and is produced and statically available
- A manual classifier is used to allow for emergency blacklisting of Hotspots. This classifier overrides all other classifiers. Hotspots are automatically removed from the manual deny list after 14 days
- The classifiers are run every 7 days to produce a new deny list and may include improvements to the previous classifiers as well as new classifiers to improve detection criteria and reduce false positives
Hotspots can be added manually to the deny list in an emergency measure but will be removed from the manual list automatically after 14 days. This allows for fast reaction while forcing the algorithm to improve within the given window of time and does not let Hotspots languish on the deny list.
Denylist Classifiers
| 🗒️ Note - This list of Denylist Classifiers is not all-inclusive and is continuously being changed and optimized to improve the algorithm. To view a detailed and up-to-date technical explanation of the Denylist Classifiers and how they work, check the Helium Denylist Evolution document. |
Terrain-Aware Signal Verification
Terrain-Aware Signal Verification utilizes public NASA Shuttle Radar Topography Mission (SRTM) data to create a terrain profile of the earth to evaluate line of sight between the asserted locations of Hotspots and their witnesses. This can detect invalid or false witnesses, such as when there is a large mountain or other terrain between the two Hotspots and signals should not reasonably make it to the other Hotspot intact.
Witness Distance Sensitivity Measurement
Witness Distance Sensitivity Measurement notes the Jaccard Index, or a measurement of how similar the activities of two Hotspots are when looking at their list of witnesses. The closer together Hotspots are geographically, the more similar their witnesses will be. As distance between Hotspots grows, their witnesses tend to differ to a larger degree. This classifier takes into account both inbound and outbound witnesses.
Witness Similarity Measurement
Witness Similarity Measurement evaluates whether the inbound and outbound witnesses for Hotspots are too similar to be explained by normal variation in physical environment and signal behaviors. Hotspots not asserted in the same physical location should not have identical or nearly identical witnesses due to the differences in the local environment, distance to other Hotspots, and random signal interference sources.
Ingest Latency Edge
Ingest Latency Edge calculations are used to determine if the time-diff of Proof of Coverage packets received by Hotspots is too close to be considered normal activity and may be the result of signal repeaters or other false Proof of Coverage mechanisms.
Antenna Splitter Hotspot
Antenna Splitter Hotspot classifier aims to identify Hotspots that are sharing an antenna. Hotspots must have their own single LoRa antenna and must not share antennas. The classifier looks at RSSI values of beacons to determine if Hotspots asserted in different geographic areas appear to be sharing an antenna.
Manual Classifier
As a backstop measure, Hotspots can be added to the deny list manually. This classifier will always add any Hotspots in the manually provided list, but will age out added hotspots after 14 days of having been added unless first removed manually.
How do I Determine if my Hotspot is on the Denylist?
A mere lack of earnings does not indicate your Hotspot is on the denylist, as there can be many different causes for flatlining. To determine if your Hotspot is on the denylist, view it on the Helium Explorer, via Moken or Hotspotty.
If the Hotspot appears normal, it is not on the denylist. Investigate other possible causes for flatlining by referring to our article on Troubleshooting Poor or No Proof of Coverage Activity.
If there is a Denylist badge attached to the Hotspot, it is on the denylist. Refer to the following section of this article for steps you can take to remove it from the denylist.
How do I Remove my Hotspot from the Denylist?
Determine the Cause
The single most common cause of legitimate Hotspots being denylisted is an incorrectly asserted location. Your Hotspot's location must be asserted in the correct hex. Asserting the location incorrectly - even one hex adjacent - can cause it to be flagged as suspicious and be denylisted.
Ensure your Hotspot's location is correct by checking it on the Helium Explorer and if issues are found, re-assert to the correct location by following the instructions in our article on How to Update Hotspot Location.
Another common cause of legitimate Hotspots being denylisted is incorrectly asserted antenna details. The antenna height and gain are used in denylist classifier calculations and should be entered accurately. Should these details need to be corrected, refer to our article on How to Update Hotspot Location, but rather than choosing "Assert Location," choose "Antenna Setup." Asserting new antenna details without changing the location assertion costs a small amount of SOL for transaction fees and does not incur a DC cost (no $10 fee as with location assertions).
Another possible cause for denylisting of legitimate Hotspots is being surrounded by actual gaming Hotspots that have been denylisted. If many surrounding Hotspots also show up on the Helium Explorer as denylisted, this could be the cause. In this case, unless you are able to directly communicate with the Hotspot's owners to convince them to resolve their Hotspots' issues, your only option would be to relocate your Hotspot to an unaffected area.
Rarely, other edge-case causes can trigger legitimate Hotspots to end up on the denylist. These would be related to the Denylist Classifiers listed in the previous section and would need more in-depth analysis to identify the cause and remediate. Should you need more assistance in determining the cause of your Hotspot being denylisted, reach out for more assistance in the official Helium Community Discord's #denylist channel. Moderators and community members frequently post and assist with reviewing denylisted Hotspots in this channel.
Correct the Issue
Once you have determined the cause of your Hotspot being denylisted, take steps to correct the issue and bring your Hotspot back into normal activity.
The denylist is updated weekly, typically on Mondays and takes into account the last week's data when refreshing. After correction of issues, it typically takes 1-2 weeks for Hotspots to be removed from the denylist, but can sometimes take up to a full month.
The process for removing Hotspots from the denylist is automated and is not controlled by any entity or company. As the denylist refreshes and recalculates, Hotspots are added or removed as necessary algorithmically.
| 🗒️ Note - Neither Nova Labs nor MNTD. can manually remove your Hotspot from the denylist or do anything to speed up the removal process. The process is automatic and will happen as data is refreshed weekly. |
Frequently Asked Questions
Will the denylist have the ability to block data transfer and/or rewards for data transfer?
Hotspots on the denylist are "denied" of Proof-of-Coverage rewards, but are still able to act as a data-only Hotspot, providing data transfer network coverage where possible. It is important to understand the uninterrupted data transfer ability in the case of errant denylist inclusions.
What if the denylist doesn't include all of the gaming Hotspots?
The denylist is one disincentive of many to keep gaming at bay. Above all, Proof-of-Coverage and more direct detection methods all work in concert to ensure the security of PoC.
What additional resources are available to learn more about the denylist?
For a deeper understanding, you can refer to the following key pages on the official Helium Docs site:
- Helium Denylist Overview
- IOT Denylist Evolution
- New IoT Denylist Classifiers
- Updated Antenna Denylist Classifier
- Official Helium Community Discord's #denylist Channel
Updated