Secure PIN Access via Secret Sharing and Trusted Identity Provider
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Solution Overview
Problem
Current eID card authentication systems are vulnerable to PIN compromise and Man-in-the-middle attacks, especially when using uncompromised card readers, as they rely on entering the PIN on potentially insecure terminals, which can lead to identity theft and unauthorized access.
Innovation Solution
Introducing a trusted identity provider and using secret sharing algorithms to securely manage PIN-based access without revealing the actual PIN, through a modified PACE protocol that involves secure multiparty computation and out-of-band communication to ensure the PIN's confidentiality and authenticity, even on compromised client systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the PIN is entered on a terminal for authentication, then the authentication process can be completed, but the PIN may be compromised by adversaries on compromised terminals
Solution Approach 1:
The PIN is segmented into multiple secret shares using secret sharing algorithms. Each secret share is distributed to different parties (user, trusted identity provider, and second computer). No single party possesses the complete PIN, making it impossible for an adversary to compromise the full PIN from any single point in the system.
Solution Approach 2:
A trusted identity provider acts as an intermediary between the user and the second computer. This intermediary facilitates the authentication process by verifying the user's secret share and coordinating with the second computer, eliminating the need for the user to input the complete PIN on potentially compromised terminals.
2Device complexity
If a simple card reader without key pad is used as terminal, then the device complexity is reduced, but the security against PIN leakage attacks is weakened
Solution Approach 1:
The mechanical key pad input method is replaced with a digital secret sharing system. Instead of physically entering the PIN on a key pad, the user provides a secret share through secure digital channels, and the authentication is performed through cryptographic verification by the trusted identity provider, eliminating the security vulnerabilities of physical key pad input.
3Loss of information
If secret sharing algorithms are used to protect PIN, then the PIN confidentiality is improved, but the system complexity increases due to modified PACE protocol
Solution Approach 1:
The PIN is pre-processed into secret shares before the authentication process begins. The trusted identity provider and second computer are pre-configured with their respective secret shares and verification credentials. This preliminary setup enables the subsequent authentication to proceed through simpler verification steps rather than requiring complex real-time PIN protection mechanisms.
Data Source
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AI summary
A computer implemented method, computer program product and computer system for securing PIN based access from a first computer (1001) to a second computer (1002). The first computer (1001) sends (5100) identifier information (ID1, ID1a), which identifies a user (1) of the first computer (1001), to at least one trusted computer (1004, 1005). The first computer receives (5200) from the user (1) a first secret share (311) of a key (400) derived from a PIN (300) used for the PIN based access, wherein the first secret share (311) results from a secret sharing algorithm and is associated with an association identifier (390) generated by the at least one trusted computer (1004, 1005) in response to the identifier information (ID1, ID1a). The association identifier (390) is further associated with at least one corresponding secret share (341, 351) of the key (400) at the at least one trusted computer (1004, 1005). The first computer (1001) generates (5310), by using the secret sharing algorithm, for an encrypted nonce value (500) received (5300) from the second computer (1002) a set of further secret shares (501, 504, 505) for the first computer (1001) and for the at least one trusted computer (1004, 1005), wherein the encrypted nonce value (500) is a nonce value (510) encrypted with the key (400) and then sends (5400) corresponding secret shares (504, 505) of the encrypted nonce value (500) to the corresponding at least one trusted computer (1004, 1005). The first computer participates (5500) in a secure multiparty computation of the nonce value (510), wherein the secure computation is based on corresponding pairs ((311,501), (341,504), (351,505)) of the secret shares (311, 341, 351) of the key (400) and the secret shares (501, 504, 505) of the encrypted nonce value (500), and wherein the computed nonce value (510) is hidden from the first computer (1001); and receives (5600) access permission from the second computer (1002) in case the secure multiparty computation results in the nonce value (510) generated originally by the second computer (1002).