In Letsfair

Letsfair has established six pillars that underpin the concept of a shared-economy application marketplace. The purpose of this series of articles is to deal with the Identity pillar.

For most Internet services, creating an access account using email and password is the first step in building a digital identity. Therefore, digital identities allow the identification of a user within a specific environment or context.

When user identity data is stored under corporate responsibility and ownership, there are imminent risks of fraud, ranging from theft of access credentials to the sale of sensitive data. The scandal involving the companies Facebook and Cambridge Analytica shows that the terms of use and privacy policies are not effective tools that guarantee the confidentiality of data and information.

Letsfair is committed to people’s right to privacy and has conducted studies on new forms of digital identity storage with a high level of privacy. It is planned to build a decentralized model, based on Blockchain technology, that allows users to control their own data.

Centralized model and lack of privacy

The report Digital Identity: Issue Analysis is the result of a detailed analysis of seven different models for the implementation of digital identities. The following figure shows the names of the models and their variations in the levels of privacy and centralization.

According to the report:

“The internet giants (Facebook and Google in particular) have built businesses around collecting information about consumers that can be used to profile customers for targeted advertising purposes. Initially information was collected from usage of the platforms, e.g. the posts made to the site or the information searched for, as well as self-asserted identity information. Logon services enable them to collect and share information with third parties, extending the presence of their brands as well as providing additional data for their profiling”. (62 p.)

In the centralized model, there are privacy risks associated with the leaking or sharing of personal data with third-party websites, often without authorization from their users. There may not be a commercial interest in ensuring privacy rights in their ideal form, with the use of technological tools as opposed to privacy policy and terms of use.

By combining the use of various cryptographic computational techniques such as Zero Knowledge Proof and technologies such as Blockchain, the No ID Provider model is the most appropriate model to be implemented for a service you want to respect the privacy of users because it is the model that offers the highest level of privacy and decentralization.

Therefore, individual autonomy is one of the essential principles of privacy and should be considered in the development of any identity system. It is possible to note that the very model of centralized data storage is against the concept of digital freedom. To allow individual autonomy, systems should give users exclusive control of their own data.


The following principles will guide the construction of a system of decentralized identities for Letsfair.

Decentralized digital identities stored in blockchains

The decentralized identity creation service will be offered by Letsfair to its users so that it can participate in the marketplace. In the future, it is expected that there will also be integration with other identity service providers to ensure individual autonomy and free choice.

Enrichment of Identity with Attributes

To conduct a buy / sell transaction, the seller can ask the buyer for certain information (an attribute). Perhaps, this information already exists in the user’s identity and it is enough for them to share it. With the increase in the use of the marketplace by users, of course, the identity of each user will be filled with data necessary for business to happen.

Enriched identity as the basis for a new digital reputation model

When any commercial transaction occurs, there will be the possibility of mutual evaluation of participants in that transaction. This means that, over time, users will be able to build a digital reputation based on business conducted among people who prove their integrity.

In order for an identity to become more complete, real, and associated with a person, attributes can be verified and validated by other members of the community. This practice will boost user confidence while reducing classic reputation scams. All of this is an online reputation system that avoids the entry of “access accounts” that do not reflect a real identity, with the intention of harming the business, gaining illicit advantages or impersonating another member of the community.

Therefore, this paper has presented the importance of properly addressing the issue of identity for the future of business in the shared economy and especially in projects such as Letsfair, which use Blockchain technology to promote business.