Decentralized policy-based permissions bounty

# Context

Linnia is a core component of the future of the web; Web 3.0. Linnia is a new Ethereum Blockchain protocol that brings the power of decentralization to your lifetime data. The Linnia protocol provides the foundation for secure decentralized applications in multiple spheres including the sphere of electronic healthcare records.

# What

We would like to incentivize you, as a member of the Gitcoin/Bounties family, to innovate and help create precise sharing permissions through decentralized policy-based permissions. The current contract, [LinniaPermissions.sol](https://github.com/ConsenSys/Linnia-Smart-Contracts/blob/master/contracts/LinniaPermissions.sol#L11), only supports (True|False) permissions. We want your help to improve this. We are expecting the improvements in the code plus an explanation document.
Decentralized policy-based permissions is a critical part of the linnia protocol. We will be awarding the submission for this task a .7 ETH bounty, assuming the below requirements are met.
The proposed Linnia policy-based permissions algorithm must be in the spirit of the following two Linnia papers;

1. https://github.com/ConsenSys/linnia-resources/blob/master/Technical-Whitepaper.md
1. https://github.com/ConsenSys/linnia-resources/blob/master/Introducing%20Linnia.pdf

Note: Linnia is a WORK IN PROGRESS. The Linnia smart contracts are only a small subset of what is described in these papers.

# Our Ideas

1. Policy-based permissions could include time-limited sharing
1. Policy-based permissions could include geography limited sharing
1. Policy-based permissions may consider data governance rules such as HIPAA or GDPR
1. Policy-based permissions may include at rest and in-flight restrictions

# Requirements

1. You have read and understood the WIP nature expressed in the README.md
1. The algorithm must:
1. Leverage the power of decentralization
1. Encompass the consumer incentives of the Linnia data marketplace
1. Allow trustless interaction
1. Be usable and easy to understand
1. It must be impossible for any party to `game` policy-based permissions
1. The various parties involved in policy-based permissions include the following;
1. Individual peers
1. Social groups or communities
1. Connected devices (e.g. IoT, Bluetooth)
1. Central authorities hosted on digital platforms (i.e. apps)
1. Central authorities hosted on physical platforms using IT (i.e. doctors, government)
1. AI and Machine learning platforms with or without blind computation capabilities
1. Decentralized applications
1. The person owning the data must remain 100% in control at all times
policy-based permissions algorithm must be end-to-end
1. Must NOT be limited to the medical
1. Your ideas must be submitted as Documentation and Code in a fork of this repo
1. Consider use of encryption to keep data secure. The computation must not leak or reveal any information related to the nature of the underlying encrypted data
1. Provide two or three real-world non-trivial end-user facing use cases for your policy-based permissions algorithm
1. Be prepared to present your submission to the Linnia team and the Linnia community
1. Be prepared for a review of your code by the Linnia team and the Linnia community
1. Finally, use your imagination and have fun