ATM Host Shared Key Establishment Without Certificate Authority
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for establishing a shared key between an ATM and a host require a certificate authority, leading to inconvenient processes and potential key leakage, as they involve offline key storage and unidirectional key transmission.
Innovation Solution
A method that eliminates the need for a certificate authority by using public keys and nounces to securely establish a shared key between an ATM and a host through a series of encrypted and decrypted operations, allowing for mutual authentication and key generation without relying on certificates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a certificate authority is used to establish shared keys between ATM and host, then security authentication is achieved, but system complexity and overhead increase due to certificate generation and verification processes
Solution Approach 1:
The patent extracts and removes the certificate authority component from the key establishment process. Instead of using a CA to issue and verify certificates, the system directly exchanges public keys between ATM and host, eliminating the intermediary CA infrastructure and its associated complexity while maintaining security authentication through direct public key verification
Solution Approach 2:
The patent introduces a key distribution center (KDC) as a simplified intermediary that pre-distributes public keys to ATMs and hosts during system initialization. This KDC replaces the complex CA certificate verification process with a simpler pre-configured public key distribution mechanism, reducing ongoing authentication overhead
2Reliability
If a manager directly visits each ATM to input and store the TMK, then key establishment is achieved, but convenience deteriorates and key leakage risk increases
Solution Approach 1:
The patent enables ATMs to autonomously establish shared keys with the host through automated public key exchange protocols. The ATM uses its pre-stored public key to receive and verify the shared key from the host without requiring manual intervention from a manager, making the system self-configuring and eliminating the need for physical visits
Solution Approach 2:
The patent performs preliminary distribution of public keys to ATMs and hosts during system initialization or manufacturing. This pre-configuration allows the devices to autonomously complete key establishment later without requiring manual key input, as the necessary public keys are already in place to facilitate automatic shared key generation
3Reliability
If unidirectional key transmission is used from host to ATM, then key distribution is achieved, but security vulnerability increases due to potential key leakage during transmission
Solution Approach 1:
The patent segments the shared key into two separate partial keys: one generated and held by the host, and another generated and held by the ATM. These partial keys are distributed separately through different secure channels, and only combined at the destination to form the complete shared key. This segmentation ensures that no single transmission channel carries the complete key, reducing leakage risk
Solution Approach 2:
The patent employs asymmetric cryptography (public key infrastructure) where the host uses its private key to encrypt the shared key, which is then transmitted to the ATM. The ATM uses the host's public key to decrypt and verify the shared key. This asymmetric approach ensures that even if transmission is intercepted, the key cannot be decrypted without the private key, preventing key leakage
Data Source
AI summary
Provided is a method and apparatus for establishing online a shared key that is required to perform a security communication between an automatic teller machine (ATM) and a host. Through this, it is possible to reduce costs and procedures that may be required to use or operate a certificate authority. Also, it is possible to reduce overheads that may occur in generating and verifying a certificate. Accordingly, it is possible to more securely prevent a leakage of the shared key.