Security Module Profile Download Authentication
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Solution Overview
Problem
Existing techniques for downloading access profiles to security modules in mobile communication terminals, such as eUICC cards, lack sufficient security measures, particularly in cases where the private key of the Certificate Issuer is compromised, allowing attackers to create false public key certificates and install unauthorized access profiles.
Innovation Solution
A method that involves obtaining a first verification datum prepared by the network operator to authenticate the server's public downloading key before initiating a secure session, ensuring that the server uses the intended secret key pair, thereby preventing the installation of false access profiles by verifying the authenticity of the public downloading key using this datum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a public downloading key certificate signed by a Certificate Issuer is used to authenticate the server, then the security of the downloading process is improved, but the system becomes vulnerable if the Certificate Issuer's private key is compromised
Solution Approach 1:
The authentication process is segmented into two independent verification steps: first verifying the server's public downloading key certificate using the Certificate Issuer's public key, and second verifying the server's public authentication key certificate using its own private key. This segmentation isolates the vulnerability scope, so that even if one verification mechanism is compromised, the other remains intact to prevent unauthorized profile installation.
Solution Approach 2:
The server performs preliminary authentication by signing the download preparation request with its private authentication key before the actual profile download begins. This preliminary action establishes a trusted session key exchange mechanism that prevents man-in-the-middle attacks and ensures that only the authenticated server can initiate profile downloads, even if the Certificate Issuer's key is compromised.
2Ease of operation
If only a public downloading key certificate is verified, then the downloading process is simplified, but false access profiles can be installed if the private key is stolen
Solution Approach 1:
The verification process is divided into two distinct segments: certificate verification using the Certificate Issuer's public key, and authentication key verification using the server's private key. This segmentation maintains operational simplicity by following standard cryptographic practices while dramatically improving reliability by adding a second layer of verification that cannot be bypassed even if the first layer is compromised.
Solution Approach 2:
A session key acts as an intermediary element that is established during the authentication phase and then used to protect the actual profile download transmission. This intermediary mechanism ensures that even if profiles are intercepted, they cannot be decrypted or modified without the session key, which is protected by the dual-verification authentication process.
3Adaptability or versatility
If the security module trusts the SM-DP+ server based on a signed certificate, then remote profile installation is enabled, but unauthorized profiles can be installed if the certificate is forged
Solution Approach 1:
Before enabling remote profile installation, the security module performs preliminary verification of both the server's certificate and authentication key. This preliminary action ensures that the server is genuinely authorized by the network operator before any profile transmission occurs, preventing unauthorized installations even if attackers manage to forge certificates or intercept communications.
Solution Approach 2:
The server receives feedback from the security module in the form of a download preparation request that includes verification of the activation code and profile identifier. This feedback mechanism allows the server to confirm that the requested profile matches the one authorized by the network operator, providing an additional layer of protection against unauthorized installations while maintaining remote installation capability.
Data Source
AI summary
A technique for downloading a profile for access to a communication network by a security module. This access profile has been prepared by a network operator and is available from a server configured to provide this access profile by downloading to the security module. The security module obtains a first verification datum prepared by the network operator. A secure downloading session is established thereafter. During establishment, session keys are jointly generated between the server and the security module and the server is authenticated by the security module using a public downloading key. The security module verifies authenticity of the public downloading key by using the first verification datum enabling verification that the server uses a secret downloading key corresponding to that provided by the network operator during preparation of the first verification datum. When the public downloading key is not authentic, the security module interrupts downloading of the access profile.