Privacy-preserving and auditable Digital Currency

This use-case provides a digital-based currency as a one-to-one counterpart to physical money or issued by debit and credit cards. This would remove the privacy issues but still allowing some opportunities of taxability or auditability by governments or its taxes agencies.


The main objective of the use case is to demonstrate the benefits of Functional Encryption that allows us to comply with complex regulations or requirements, without compromising the functionality of the whole system.



The use case will demonstrate how a digital coin with a proper level of privacy could benefit the society from different perspectives:

  • End-users would be able to perform transactions without exposing their private information to banks and government.
  • Public administrations could use the tool to tax business and users, reducing underground economy.
  • Merchants would have a cost-effective tool to enable digital micropayments.


The main potential beneficiaries of this use case are:

  • Bank and Financial Service Providers.
  • Public administrations.
  • Merchants.


The technical work will follow an Iterative and Incre-mental development approach, an alter-native methodology. This decision comes from the particularities of and complexity of intro-ducing FE into an existing payment platform that requires modifying different programmatic modules and interfaces. This methodology allows the division of the work into subtasks or functions of the whole functionality.

The process consists of repeating a set of steps recursively for each of the subtasks: analysis, design, implementation, and testing. Once a subtask is finalized the result is integrated into the platform, which is built by adding functions progressively.

Previous work

Previously, this pilot has worked on the development of the core functionality of a payment platform based on Blind Signature scheme.

Current work

Currently, this FENTEC pilot is working on the integration of KP_ABE encryption scheme into the Coin generation and payment steps.

Next steps

Next step for Atos pilot will be the integration of the KP-ABE scheme and to enhance payment platform by splitting the current class structure into services.


The biggest challenge here is to achieve the integration of KP_ABE into the payment process without leaking any information to the exchange which let to link a payment with a wallet.