Secure Software Update Transmission for Security Elements
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing software update mechanisms for security elements, such as chip cards, can compromise security due to side channel attacks and limited computational resources, and fail to ensure confidentiality and authenticity of update data.
Innovation Solution
A method involving encryption with a cipher to generate multiple ciphertexts and corresponding check values, along with signature verification, ensures secure transmission of software updates by using encryption key K ENC and check value key K MAC, and includes a signature verification process to authenticate the data set before installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If software update mechanisms are implemented on security elements, then functionality can be updated and improved, but security can be compromised through side channel attacks and security gaps
Solution Approach 1:
The patent applies preliminary action by performing authenticity verification and encryption key establishment before the actual software update installation. The update package is authenticated and the secure channel is established in advance, ensuring that only verified updates are installed, thus preventing security compromises during the update process
Solution Approach 2:
The patent introduces an intermediary secure communication channel between the terminal and security element. This channel uses encryption keys stored in the security element to authenticate update packages and transmit update data securely, acting as a mediator that prevents direct attacks on the update mechanism
2Reliability
If encryption and authentication mechanisms are added to software updates, then security is improved, but computational resources and memory capacity are exceeded
Solution Approach 1:
The patent segments the update process into distinct phases: authentication phase (verifying update package signature), key establishment phase (deriving encryption keys), and data transmission phase (sending encrypted update data). This segmentation allows each phase to use appropriate security measures without overwhelming the security element's computational resources at any single moment
Solution Approach 2:
The patent applies local quality by using different security mechanisms appropriate to each stage of the update process. The security element uses its limited resources for critical operations (authentication and key storage) while the terminal handles more computationally intensive tasks (encryption/decryption of large update data), matching security strength to local capabilities
3Speed
If update data is transmitted unencrypted, then transmission speed is improved, but confidentiality is compromised allowing reverse engineering
Solution Approach 1:
The patent extracts the confidentiality requirement from the transmission process itself and handles it separately through pre-established encryption keys stored in the security element. The update data is encrypted using these extracted keys, allowing confidential transmission without requiring complex real-time encryption protocols that would slow down transmission
4Reliability
If authenticity checks are performed on update data, then security is improved, but update installation time is increased
Solution Approach 1:
The patent performs authenticity verification as a preliminary action before update installation begins. The terminal verifies the update package signature and authenticates the data using encryption keys from the security element in advance, so that once authentication succeeds, the actual update installation can proceed quickly without repeated verification delays
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method (200) for securely transmitting user data from a background system, in particular a server, to a security element. The method (200) comprises: providing (201) an encryption key KENC and a checksum key KMAC on the security element; encrypting (203) the user data using the encryption key KENC and a cipher to obtain at least a first ciphertext c1 and a second ciphertext c2;the transmission (205) of a data record to the security element, wherein the fully transmitted data record comprises the first ciphertext c1, the second ciphertext c2, a check value of the first ciphertext h(c1), a check value of the second ciphertext h(c2), a check value of a first key-based check value h(MAC1), wherein the check value of the first ciphertext h(c1) is included in the first key-based check value MAC1, a check value of a second key-based check value h(MAC2), wherein the first key-based check value MAC1 and the check value of the second ciphertext h(c2) are included in the second key-based check value MAC2, and a signature of the check value of the first ciphertext and the check value of the first key-based check value Sign1[h(c1)||h(MAC1)]. The invention further relates to a correspondingly configured security element and a correspondingly configured background system.