Embedding Auxiliary Data in One-Time Passcodes
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Solution Overview
Problem
Existing token-based user authentication systems face challenges in securely transmitting auxiliary information, such as token integrity and key material, alongside one-time passcodes, and are vulnerable to typographical errors and malicious tampering.
Innovation Solution
The method involves embedding auxiliary information into one-time passcodes using a secret key to generate a codeword, which is combined with a tokencode to create a secure passcode, providing resistance to errors and tampering through error-correction codes and forward-secure pseudorandom number generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary information is embedded in passcodes using conventional techniques, then auxiliary information can be transmitted, but the system becomes vulnerable to typographical errors and malicious tampering
Solution Approach 1:
The patent applies error-correction codes that provide beforehand cushioning against typographical errors. The codebook is constructed with codewords spaced at minimum distance d, allowing the system to detect and correct errors before they compromise authentication. This cushioning mechanism protects against harmful factors without requiring complex verification procedures during authentication.
Solution Approach 2:
The patent introduces an intermediary error-correction code layer between the auxiliary information and the passcode. This intermediary structure (the codebook with minimum distance d) mediates the relationship between embedded information and transmission, providing protection against tampering while maintaining the passcode's authentication function. The intermediary layer absorbs the impact of malicious tampering attempts.
2Loss of information
If auxiliary information is embedded in passcodes, then additional information can be transmitted, but the passcode structure becomes more complex
Solution Approach 1:
The patent merges the auxiliary information transmission function with the existing passcode structure. By embedding codewords into passcodes and using them in the authentication equation (passcode = f(token, time) XOR codeword), the system combines multiple functions (authentication and auxiliary information transmission) into a single integrated structure, avoiding additional complexity in the overall system architecture.
Solution Approach 2:
The passcode structure is designed to serve multiple functions simultaneously: authentication, auxiliary information transmission, and error correction. The codebook with minimum distance d provides universal protection against various types of attacks while maintaining compatibility with existing authentication mechanisms, eliminating the need for separate complex verification systems.
3Loss of information
If conventional embedding techniques are used, then auxiliary information can be transmitted, but efficient extraction of embedded messages requires brute-force searches
Solution Approach 1:
The patent implements a feedback mechanism where the authentication server receives the passcode, extracts the codeword, and verifies it against the codebook. This feedback loop allows efficient message extraction by comparing the received passcode with expected values, eliminating the need for time-consuming brute-force searches. The minimum distance d property of the codebook provides feedback that enables rapid verification of embedded information.
Data Source
AI summary
Methods and apparatus are provided for embedding auxiliary information in one-time passcode authentication tokens. Auxiliary information is embedded in authentication information transmitted to a receiver by obtaining the auxiliary information; and mapping the auxiliary information to a codeword using a secret key, wherein the secret key is shared between the security token and an authentication authority; and combining the codeword with a tokencode generated by a security token to generate a one-time passcode. The one-time passcode can then be transmitted to the receiver.