Distributed Private Key Splitting for Secure Authentication
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Solution Overview
Problem
Existing user-authentication methods, particularly those relying on shared secrets and asymmetric cryptosystems, face challenges in securely managing private keys for revocation and updates, with Certificate Revocation Lists (CRL) exhibiting vulnerabilities that can be exploited by attackers.
Innovation Solution
A system and method that splits a user's private key into two portions, each requiring independent authorization, where one portion is stored on a first user device and the other on a remote server, with a second user device involved in authentication to ensure secure key management and digital signature generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single private key is stored on one device, then authentication is simple and fast, but security is compromised because the key can be stolen or revoked keys cannot be properly managed
Solution Approach 1:
The private key is divided into multiple key portions distributed across different devices (first user device, second user device, and/or server). Each key portion can be used to generate a corresponding key share. This segmentation ensures that no single device holds the complete private key, preventing theft and enabling proper key revocation while maintaining authentication functionality through the distributed key shares.
2Reliability
If multiple key portions are distributed across devices, then key security and revocation capability are improved, but the authentication process becomes more complex requiring coordination between multiple devices
Solution Approach 1:
A server acts as an intermediary to facilitate the authentication process. The server receives key portions from different devices, verifies their validity, and coordinates the authentication. This intermediary approach simplifies the user experience by centralizing the coordination logic while maintaining the security benefits of distributed key portions across multiple devices.
3Adaptability or versatility
If Certificate Revocation Lists (CRL) are used to manage key revocation, then key updates can be communicated to systems, but the system becomes vulnerable to attacks that can bypass revocation mechanisms
Solution Approach 1:
The vulnerable CRL mechanism is extracted and replaced with a direct key portion revocation approach. When a key needs to be revoked, the system directly removes or invalidates the specific key portions from the distributed devices rather than relying on CRL publications. This eliminates the vulnerability to CRL bypass attacks while maintaining the ability to update and revoke credentials effectively.
Data Source
AI summary
A method according to preferred embodiment can include receiving a request at a server from a private key module associated with a first user device; directing a request for a first portion of the private key from the server to a second user device; and in response to a successful user challenge creating a first portion of a digital signature and a second portion of a digital signature at the server. The method of the preferred embodiment can further include combining the first portion of the digital signature and the second portion of the digital signature; and delivering the digital signature to the first user device. The method of the preferred embodiment can function to secure the digital signature process by splitting or dividing the user's private key into two or more portions, each of which require independent authorization from the user in order to create the digital signature.