Faceless

The payment scheme of the existing blockchain networks such as Solana is based on blockchain addresses, which are usually random strings that are hard to memorize and manage. Therefore, it might lead to many inconveniences for the users such as funds being transferred to the wrong address. In contrast, traditional payment is usually based on human-readable identifiers (HRI) instead of random strings, and this is for a good reason. For instance, when you pay your debts to your friends, you want the transaction record to be bound to your identity so that it can serve as proof later that your debt has been paid.  
 The existing HRI solutions such as SNS usually focus on one specific blockchain ecosystem and fails to incorporate many existing Web 2.0 human-readable identifiers that users are more comfortable using in practice, such as their mobile phone numbers, various social media accounts, email addresses (based on which PayPal systems are built), etc. We believe it is far more interesting to build a cross-platform payment scheme based on a generic HRI system that combines the users' existing Web 2.0 and Web 3.0 identifiers. A cross-platform payment scheme based on a generic HRI system will not only serve the purpose of bringing Web 2.0 users into the Web 3.0 world but also taps into this immense market and helps realize the full potential of Web 3.0. 
 Another limit of existing HRI-based payment solutions is the lack of privacy. This is actually closely tied to another interesting application of Faceless protocol, i.e., regulatory-compliant payment. Due to the explosive growth of Web 3.0 payment and its applications such as DeFi, NFT, etc, traditional financial institution is starting to migrate to Web 3.0. However, in order for the Cryptocurrency market to attract institutional money on a large scale, one has to address its regulatory concerns. The privacy issue is likely to play a central part in the regulatory compliance requirements. Faceless will provide a private payment scheme based on HRI and hence resolve the privacy issue.  
 Our protocol will become a fierce competitor in the sphere of regulatory-compliant payment. In the Web 3.0 world, the HRIs will serve as the basis of regulatory-compliant finance. Faceless satisfies two vital requirements of regulatory compliance: 1. HRI will serve as the basis of regulatory compliance, 2. Our payment solution will be private, which addresses a central issue in any regulatory-compliance requirement. One's HRIs such as mobile numbers or social media accounts can serve as the foundation to implement various regulation-compliant operations such as anti-money laundering. More sophisticated applications such as trusted decentralized finance (DeFi) can also be built on top of our system. For instance, one could build a credit system or lending and borrowing system based on one's HRIs. 
 Our scheme is based on a combination of identity-based encryption (IBE) and zero-knowledge proof. Identity-based encryption scheme will allow the users to encrypt the payment under the receiver’s identity instead of random blockchain addresses, and it will also allow the users to manage their multiple HRIs with one single master key, which is a significant usability advantage. Our architecture will introduce a mechanism, which is based on randomized signature, to verify the authenticity of the user identity while protecting the users’ privacy. The verifiable identity will therefore serve as a foundation of regulatory-compliant payment. On the other hand, we will apply the zero-knowledge proof and IBE scheme to protect the users’ financial privacy. We will provide an open-source library to demonstrate the feasibility of our concrete design.  
 The final product of Faceless protocol will be a layer-2 protocol, which can be deployed on smart contract platforms such as Solana. We will potentially introduce a zk-rollup scheme to further improve the scalability of our payment scheme. Our rollup scheme will mainly focus on resolving the conflict between the scalability issue and regulatory compliance requirements. 

This project has been supported by Web 3.0 grant: https://github.com/w3f/Grants-Program/blob/618be8639cc91cfaf779f470444e8c271221030e/docs/accepted_grant_applications.md, and we have already delivered milestone 1: https://github.com/HeisenbergLin22/Grant-Milestone-Delivery/blob/patch-1/deliveries/faceless_milestone1_delivery.md.