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Medusa

Simple programmatic access control without keys

Medusa is a network of nodes that allows dApps to build complex access control systems onchain without having to manage keys!

Medusa can be used to manage access in different scenarios:

  • A decentralized NFT-gated content platform
  • A private content distribution platform like OnlyFans onchain
  • In general, fair exchange of any private data

One can think of Medusa as similar to a price oracle. Instead of enabling onchain price feeds, Medusa enables re-encryption / decryption of data onchain.

Overview

An example workflow​

Imagine Alice wants to sell a picture of her cat for 1 DAI on an eBay-like dApp.

1. Uploading​

Alice encrypts the cat picture to the Medusa network and registers the encryption and the price to the dApp platform.

2. Buying​

When Bob wants the buy the cat picture, he sends one 1 DAI to Alice via the dApp platform. At this point, the dApp smart contract requests Medusa to reencrypt the cat picture to Bob.

3. Reencryption to Bob​

Medusa verifies that the cat was submitted to the same platform that requested the reencryption. If so, Medusa nodes perform their operation offchain and submit the resulting reencryption onchain.

4. Local decryption​

Bob sees the event that the reencryption has been submitted, and can now locally decrypt the cat picture!

Important

Only Bob can decrypt the cat picture. Medusa's threshold encryption protocol ensures the dApp and Medusa nodes cannot decrypt and see the cat picture.