Soft-Token Authentication with PIN-Protected Shared Secrets
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Solution Overview
Problem
Existing soft-token systems are vulnerable to theft and misuse due to stored credentials, are susceptible to brute-force attacks on PINs, allow credential copying, and impose computational burdens on small devices, limiting their effectiveness in providing strong authentication without additional hardware.
Innovation Solution
A soft-token system using a shared secret encrypted with a cryptographic hash of the user's PIN, which changes with each use, ensuring that the PIN cannot be guessed without authentication attempts and preventing unauthorized duplication, while keeping the PIN secure on the user's device and unknown to the remote server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If soft-token credentials are stored in a certificate store or key chain, then authentication functionality is enabled, but the system becomes vulnerable to theft and misuse by malware and malicious users
Solution Approach 1:
The patent extracts the soft-token credentials from the standard certificate store or key chain and places them in a secure element or trusted execution environment. This separation removes the credentials from the vulnerable general-purpose storage while maintaining authentication functionality through controlled access interfaces.
Solution Approach 2:
The patent introduces a secure element or trusted execution environment as an intermediary layer between the authentication application and the credential storage. This mediator provides isolated, protected storage that prevents direct access by malware while allowing authenticated access by legitimate applications.
2Reliability
If credential data is encrypted with a PIN, then protection against unauthorized access is improved, but the system becomes vulnerable to brute-force attacks on the user's PIN
Solution Approach 1:
The patent implements rate limiting and account lockout mechanisms as preliminary actions before brute-force attacks can succeed. After a predetermined number of failed authentication attempts, the system temporarily or permanently locks the account, preventing exhaustive PIN guessing while maintaining security through controlled access.
Solution Approach 2:
The patent incorporates feedback mechanisms that monitor authentication attempt patterns and dynamically adjust security responses. When abnormal patterns suggestive of brute-force attacks are detected, the system increases security measures such as locking accounts or requiring additional verification, creating a feedback loop that adapts to threat levels.
3Stability of the object's composition
If soft-tokens use a stored credential that changes infrequently, then authentication consistency is maintained, but the credential can be copied and used on other devices
Solution Approach 1:
The patent implements dynamic credentials that change frequently through mechanisms such as time-based one-time passwords (TOTP) or challenge-response authentication. Instead of static credentials, the system generates unique authentication values for each login attempt or time interval, making copied credentials immediately useless while maintaining consistent authentication through synchronized generation on both client and server sides.
Solution Approach 2:
The patent employs periodic credential rotation where authentication credentials are automatically updated at regular intervals or after a predetermined number of uses. This periodic change ensures that even if credentials are compromised, the window for unauthorized use is limited, and consistent authentication is maintained through automated synchronization of the rotation schedule across systems.
4Reliability
If soft-token systems require asymmetric operations on the device, then security is enhanced, but computational requirements degrade user experience on small mobile devices
Solution Approach 1:
The patent extracts the computationally intensive asymmetric cryptographic operations from the mobile device and relocates them to a remote server or cloud-based authentication service. The mobile device retains only lightweight operations such as generating authentication requests and verifying simple tokens, dramatically reducing computational requirements while maintaining security through server-side cryptographic processing.
Solution Approach 2:
The patent introduces a server-based authentication intermediary that handles complex cryptographic operations. The mobile device communicates with this intermediary, which performs the heavy lifting of asymmetric cryptography and returns simplified authentication tokens or verification results, enabling secure authentication without burdening the device's limited computational resources.
Data Source
AI summary
A system for authenticating a user and his local device to a secured remote service with symmetrical keys, which utilizes a PIN from the user and a unique random value from the local device in such a way that prevents the remote service from ever learning the user's PIN, or a hash of that PIN. The system also provides mutual authentication, verifying to the user and local device that the correct remote service is being used. At the same time, the system protects against PIN guessing attacks by requiring communication with the said remote service in order to verify if the correct PIN is known. Also, the system works in such a way as to change the random value stored on the user's local device after each authentication session.