New Post: The Anatomy of a Zone


As the first in a new series of blog posts on Dynamic Proof of Location “The Anatomy of a Zone” has just been published.

In this post we will examine more closely the “Anatomy of a Zone” and try to answer What is a Zone? What does a well formed Zone look like? How can a Zone be trusted? and What is the incentive to be a Zone operator? While topics such as staking tokens, mining rewards and verification will be touched on, each will have their own dedicated future post, the focus here is on what makes a Zone. Let’s get started!

In addition to this post, please join our upcoming Community call this Thursday January 24th at 12pm est. We will be going over this post as well as diving into and demonstrating the current state of the hardware and protocol research.


would love to get a better idea on where the mobile verifier actor came from.

what was the initial inspiration? was there always consideration for an actor like this to eventually be included or did the neessity only come up when the team started to suss out actual Zone mechanics?

what are the possible attack vectors for this? (could a hopeful Zone bribe verifiers? would there be any gain from this long term?) should multiple verifiers be required per new zone?

reputation is an tough problem not only in the crypto space but also in larger app ecosystems. each construction has tradeoffs. will FOAM be developing a novel in-house solution (tailored to geolocation network management) or be leaning on area experts to facilitate?



The notion of challenges by mobile actors to suspicious zones has been a concept, but is not addressed in the previous draft paper.

The necessity comes from when a Zone emerges in isolation from any pre-existing Zone. How do you know it is there and not simulating a Zone like Ilya demonstrated on the community call.

It will not be based on the number of verifiers but on the amount of tokens in total bonded to the verifiers that attest to the new Zone. This means a percent of all tokens need to be used and almost certainly this means multiple verifiers. This threshold is not yet hardcoded. The amount needed may also depend on the Zones weight in other factors. Yes it could be possible to bribe verifiers, but a sufficient challenge function would make this undesirable, as all actors need to have tokens at stake which at any point could be lost.

The reputation is meant to be fairly objective and will take into consideration 1. How many Presence Claims from established Zones does the Verifier have and 2. How many tokens the Verifier has bonded on chain.


gotcha - this makes sense. I had assumed a more complicated rating / reputation scheme.


“Primarily, the weight of the zone is based on length of clock synch messages that can be found the root chain, meaning how long has the Zone been claiming to correctly run the protocol and publish that data publicly. This weight is moreover affected by the total coverage area of that Zone, the bonded weight of its tokens on chain as well as added weight from Signals if it is operating in such an area. Further, servicing location customers and issuing Presence Claims contributes to the weight and demonstrates use.”

Thus we see the significance of Signaling, the curation of the, is key to building the functions that the users of FOAM need. In the next paragraph we can see how a hardware ecosystem will emerge. The Mobile Verifier, while initially human controlled, will very rapidly be able to support autonomous features based on local regulations and the use of fully autonomous drones is entirely possible. Think about the thousands of dollars we spend currently on datacenter Mining Rigs, and how a light-weight commodity drone for instance from DJI, could be augmented to performed the “Mobile Verifier” function based on a greater cost benefit ratio. This is the inherent benefit of blockchains that move to leverage a PoS system. Your greatest expenditure is not hardware or electricity. It is interfacing to a global dPoL protocol that has already functional components that you can leverage to support your locational need.

" However, other than becoming contiguous with a TFAR recognized Zone a Dark zone is to issue a Presence Claim to a “Mobile Verifier” . This is a new actor in the protocol. While a Verifier node runs on a computer to check the logs of Zones, Mobile Verifiers are to physically visit Zones, purchase Presence Claims and contribute to their weight. Mobile Verifiers will have their own reputation and will need to bond tokens to participate. Another functionality of the Mobile Verifier is that it can issue challenges against Zones it believes are not there with bonded tokens."

With full transparency, the governance function of FOAM will be realized.

" What is more is that the weight contributed to a Dark Zone by Mobile Verifiers is not by the number of Mobile Verifiers but by the cumulative amount of FOAM Tokens bonded by the Mobile Verifiers. This means that a certain percentage of the FOAM Token Supply needs to be bonded in attestations to the Zone , which prevents Mobile Verifier Sybil actions."

This demonstrates on chain the interest in the FOAM protocol, will be an audit-able measure of sentiment, and the handling of these “Mobile Verifiers” a function that will improve synergies between the “Total FOAM Area Reward” Zones and emergent “Dark Zones”.

I conclude that this demonstrates flexibility in moving FOAM forward and has opened some very interesting avenues for hardware manufacturers to capitalize on a new segment of the Blockchain industry. The vertical integration of Hardware mining, has become capital and resource intense, the competition is quite severe, and I believe that there is an interest in building something that can cater to an application with immediate PoS real-world use.

Updated: to use blockquotes for the info from the blog post.


Wow, really fantastic post! Thank you for sharing. I will return with a more detailed follow up, but one quick point for now:

Thus we see the significance of Signaling, the curation of the, is key to building the functions that the users of FOAM need. In the next paragraph we can see how a hardware ecosystem will emerge. The Mobile Verifier, while initially human controlled, will very rapidly be able to support autonomous features

Agreed and well put! I wanted to add that beyond the establishment and verification of Zones and the user class of Mobile Verifiers, location customers of the system will want to purchase presence claims and interact with the Zone and may very well be an autonomous actor.

On the application layer, for example a drone delivery, the architecture of the smart contracts would set the conditions for what Presence Claim is acceptable in order for the drone to receive payment. The logic of that application would also want to reference geodata i.e. Points of Interest and as a web3 application instead of querying off chain data it can reference the FOAM Map Registry of Points. This also adds the aspect that points will accumulate “hits” i.e. how often they are called or referenced in contracts which could add an interesting dimension to the curation process. Applications like this example can also drive demand for a more robust registry for the smart contracts to reference.


Precisely. This is why API access should always be the priority, and the UI built on top of that. My reading of the current FOAM design is that is your intent. Just something to keep in mind.

In the whole it can become an economy where FOAM are used to buy services, and in paying for those services in FOAM a virtuous cycle emerges. I think this is what you were explaining as far as Signaling is like answering a survey, and you are rewarded if you answer correctly. As long as the system is balanced, a small input of FOAM should allow the successful completion of many support functions.

Thus a healthy FOAM ecosystem grows, and with this tie-in to the physical world, a number of existing applications can be automated on the FOAM protocol. This is the promise of blockchain and how it will further improve productivity going forward. While automation is a component, the ability to account for value transfer, and herein the FOAM protocol delivers that value of Proof of Location, transferred as required, with features not available in Legacy Localization techniques; that FOAM assures privacy, security, and immutability.


This is hands down the best post on the entire forum, bravo.