Private key management is one of the biggest barriers to blockchain usability and mainstream usage. However, with biometric technology and fuzzy extractors[1], private keys can be securely stored and recovered whenever needed. This also enables the end user to never handle their raw private key and solely use their biometric data.
[1]Fuzzy extractors basically allow you to generate the same private key from a slightly different input. See the PDF for a more in-depth description.
Matrix is a private key recovery and access system that can be used for blockchain and other decentralized systems. Matrix utilizes the user's biometrics in order to create an unforgettable and almost impossible-to-lose encryption key. We don't hold any of the users' information, biometric or otherwise.
Initially, we'll be building on iPhone X's TrueDepth camera and using the ARKit.
The use of the biometric data depends on fuzzy extractors, which allows us to generate the same encryption key from slightly different data.
In order to have extra security, the ciphertext can be split between a user's social group and recombined with Shamir's Secret Sharing.
When the user loses their private key, they go onto the app and request the split ciphertext from n members of their social circle (n can be set to whatever). The user starts a video call with each member and that person verifies that the user is actually real. If they believe that the person is real, they send over their piece of the ciphertext (with a time delay for plausible deniability. The sending can be canceled at any time.) Once the user has collected each piece, they reconstruct the ciphertext and decrypt it with their biometric data.
We want to prevent this.