Monotonic Counter Secured Encryption Key Storage
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Solution Overview
Problem
Current methods for storing encryption keys in processing devices lack sufficient security, as they are vulnerable to unauthorized access and do not effectively prevent access to encryption keys based on count values.
Innovation Solution
A method and device utilizing a monotonic counter to generate count values, which are used to select and provide encryption keys to a cryptographic processor, with a selection circuit configured to prevent access to other encryption keys, ensuring secure access based on specific count values and storage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption keys are stored in memory for cryptographic operations, then the cryptographic processor can perform decryption, but the keys become vulnerable to unauthorized access
Solution Approach 1:
The memory is divided into multiple banks (first bank, second bank, third bank) that are selectively accessible based on count values. Each bank stores specific encryption keys associated with particular count value ranges, preventing unauthorized access to all keys simultaneously while enabling cryptographic operations when needed.
Solution Approach 2:
Encryption keys are pre-associated with specific count values and stored in corresponding memory banks before cryptographic operations occur. The system prepares the key selection mechanism in advance by organizing keys according to count value ranges, so that when a cryptographic operation is needed, the appropriate key is already positioned for retrieval based on the current count value.
2Adaptability or versatility
If multiple encryption keys are stored in memory for different operations, then versatility is improved, but security is reduced due to potential access to other keys
Solution Approach 1:
Multiple encryption keys are stored in segmented memory banks with controlled access. The first bank stores keys for first count values, the second bank for second count values, and the third bank for third count values. This segmentation allows the system to support multiple cryptographic operations with different keys while preventing access to keys associated with other count value ranges.
Solution Approach 2:
Different memory banks have different access characteristics based on count values. The selection circuit enables local access to specific banks based on the current count value, providing tailored access control for each key group. This allows versatile key storage while maintaining security through location-specific access rules.
3Reliability
If a monotonic counter is used to control key access, then security based on count values is improved, but device complexity increases
Solution Approach 1:
The memory is segmented into multiple banks that can be independently controlled by the monotonic counter. This segmentation allows the counter to selectively enable access to specific banks based on count value ranges, providing robust count value-based access control while distributing the complexity across manageable memory segments rather than requiring a single complex control structure.
Data Source
AI summary
The present disclosure relates to a method for performing a cryptographic operation, the method including generating a first count value by a monotonic counter of a processing device, transmitting the first count value from the monotonic counter to a memory of the processing device, selecting a first encryption key from the memory based on the first count value, and providing the selected first encryption key to a cryptographic processor.