Vending Machine Bus Security via TPM and Data Tuples
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Solution Overview
Problem
Self-service machines, such as ATMs, lack security features in their USB connections, making them vulnerable to manipulation and unauthorized access, which can lead to illicit cash dispensing and data theft.
Innovation Solution
A method and device that secure the communication channel between a main control unit and peripheral devices using a combined process for authenticity, confidentiality, fault tolerance, and preventing message replay, employing encryption and authentication keys stored in a Trusted Platform Module (TPM), with a data tuple (C, A, R, N, Z) that includes message and session counters to manage key changes and detect packet loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If USB connections are used to connect peripheral devices to the main control unit, then ease of connection and device versatility is improved, but security and protection against unauthorized access deteriorates
Solution Approach 1:
The patent introduces a security module as an intermediary between the main control unit and peripheral devices. This module handles all security-related operations including authentication, encryption, and key management, allowing USB connections to remain versatile while being protected through the intermediary security layer that mediates all communications.
Solution Approach 2:
The patent replaces mechanical/physical security measures with cryptographic mechanisms. Instead of relying on physical security alone, the system uses encryption algorithms, authentication protocols, and key management systems to secure USB connections, substituting physical security with information-theoretic security.
2Object-affected harmful factors
If encryption and authentication mechanisms are implemented, then security against manipulation and unauthorized access is improved, but device complexity and computational requirements worsen
Solution Approach 1:
The patent segments security functions into distinct modules: authentication module, encryption module, key management module, and security protocol module. Each module handles specific security tasks independently, making the overall system more manageable and easier to implement while maintaining strong security protection through modular architecture.
Solution Approach 2:
The patent implements preliminary authentication and key exchange actions before allowing any data transmission. By performing security setup in advance (authentication, establishing encryption keys, configuring security parameters), the system ensures security is built-in from the start rather than added as an afterthought, reducing runtime complexity.
3Reliability
If message authentication and encryption are performed for each communication, then authenticity and confidentiality are improved, but communication speed and productivity worsen
Solution Approach 1:
The patent implements periodic security operations rather than continuous ones. Security protocols are applied at specific intervals and at critical transition points (when establishing connection, when receiving new commands, when dispensing cash), rather than continuously processing every byte, allowing authentication and encryption to be performed periodically without significantly impacting communication speed.
Solution Approach 2:
The patent dynamically adjusts security measures based on the communication context and threat level. The system can switch between different authentication and encryption strengths depending on the operation being performed, allowing faster communication for low-risk operations and stronger security for high-risk operations, thus optimizing the balance between security and speed.
Data Source
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AI summary
The invention relates to a method for securing the communication of components within vending machines that are connected to one another via a bus system, having a transmitter and a receiver, characterized in that data are exchanged on the transport level of the bus system as tuples (C, A, R, N, Z), wherein - C are those tuples having encryption key encrypted message data M, - A are those having authentication key authenticated message data M, - R represents the role of a component on the bus system of active or passive participants, - N represents a message counter, - Z represents a session counter.