How wysker is using the Blockchain

Kai Jäger
Oct 9, 2017 · 5 min read

One of the core tenants of data privacy is that not all data is created equal. Some data points have the power to identify a person uniquely while others can only identify larger groups. A zip code for example may stand for thousands or tens of thousands of households while a last name might only be shared by a handful of people. If a stranger asked you what your favorite color was, you would most likely give a truthful answer, but asked about your social security number you’d probably have the good sense not to respond. The real trouble starts when various seemingly harmless data points are combined. If you live in the U.S., the combination of your date of birth, gender and ZIP code has an 87% chance of identifying you uniquely [1] — no name required. Digital advertising uses exactly this phenomenon. At this very moment, somewhere in the Cloud is a database that holds detailed information about you: websites you looked at, things you shared and liked on Social Media, the people you know and interact with, where you’re from, how much you spend on what, your age and gender and possibly a pretty accurate estimate of your sexual orientation [2]. If each of these data points by itself seems innocent enough, the fact that someone has collected all of them under a single ID should give you ample reason to be concerned.

“the combination of your date of birth, gender and ZIP code has an 87% chance of identifying you uniquely”

With wysker, we took the opposite approach: carefully separating data that is anonymous from data that could potentially be used to identify you. Before we get into this, let’s examine what wysker knows about you:

You, according to wysker

When you first launch the wysker app, you are asked to provide a few bits of information: what style of products you are interested in and whether you are looking for things aimed at men, women or both. We also geo-locate you, albeit very coarsely (country and city), so not to show you products from stores that do not ship to your area. We do not ask your name, age or email address, quite frankly because we don’t need to. By most modern standards, this wouldn’t be considered PII (or personally identifiable information), because your preferred style, gender identity and the city you live in are not sufficiently unique.

The much more interesting set of data points we collect however relates to how you use the wysker app. We carefully track what products you look at, for how long and how often, which products you double tap and which ones you actually buy. Because this would otherwise be a massive amount of data, we transform this information into aggregate views that reveal preferences around brands, colors, styles, shapes, product categories, price ranges and ultimately buying intent. This data by itself still isn’t sufficient to uniquely identify you, but you probably wouldn’t want it linked to data that could.


One of the main pillars of the wysker philosophy is that you own your data. You can choose to share it, or you can keep it to yourself, but you never have to give up control. With data, ownership usually equals access. If you are the only one who can access a piece of data, it can reside on someone else’s computer without you losing ownership. wysker works much the same way: your data resides on wysker servers, but you are effectively the only one with access.

“wysker may know that someone in Paris is interested in red sneakers, but unless you come forward, nobody can know that it is you”

This is of course a slight over-simplification. One of the roles that wysker assumes in providing its platform is that of a matchmaker. An advertiser can specify who they are looking to reach and the wysker platform needs to be able to say with some certainty if those people exist and how many of them there are. For example, a shoe brand may be interested in presenting their products to wysker users who have previously shown an interest in red sneakers. For the wysker platform to be able to respond to this request, it needs to know if anybody fits this profile. The trick that wysker applies to make this work without compromising data ownership is to store data anonymously and to allow users to claim their data by proving they control a cryptographic key. This is effective, because unclaimed, the data is merely of statistical value. In simpler terms, wysker may know that someone in Paris is interested in red sneakers, but unless you come forward, nobody can know that it is you.

Enter the Blockchain

When an advertiser creates a new campaign, they specify who they would like to reach and how many wys Tokens they are willing to spend to get their products in front of wysker users matching their criteria. The wys Tokens are subsequently transferred from the advertiser’s wallet to a smart contract running on the Ethereum blockchain. Once the campaign fund is established, wysker users can claim a share of the wys Token reward by completing two steps. During the first step, participating users need to prove their ownership of eligible data by means of their cryptographic key. This causes the contract to issue a “lease” that gives advertisers temporary access to the user’s data and the right to present the user with product recommendations. Once the user has viewed the product recommendations, they are issued a confirmation code. This code is then submitted to the smart contract in the second and final step, causing the release of the wys Token reward. In this setup, the smart contract operates both as an escrow service and to perform a kind of “rights management”. Once the campaign is over, any unspent funds are returned to the advertiser and access to all user data is revoked.

All of this happens largely behind the scenes and neither the user nor the advertiser need to know about the intricacies of the wysker Platform or the Ethereum blockchain. Either way, they benefit from the absolute transparency of a decentralized system and the assurance that their respective interests are enforced by an incorruptible smart contract that knows no bias and doesn’t bow to greed.



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