Memory Encryption via Separate Stream Ciphers
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Solution Overview
Problem
Current computer memory systems face challenges in securely protecting data and instructions shared between memory controllers and memory, particularly in ensuring the integrity and confidentiality of data and addresses, which is essential for proprietary information and complex applications.
Innovation Solution
The implementation of separate stream ciphers for write and read channels using shared security resources, including link-pad generators and encryptors/decryptors, to encrypt and decrypt data and addresses, ensuring secure communication and preventing unauthorized access by using synchronized pad values for each memory transaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate stream ciphers are implemented for write and read channels, then data security and confidentiality are improved, but device complexity increases due to requiring separate encryptors/decryptors and synchronized pad value generation for each channel
Solution Approach 1:
The encryption system is segmented into separate write and read channels, each with its own stream cipher instance. This segmentation ensures that encryption operations for writes and reads are independent and can be performed simultaneously without interference, thereby improving data security while managing complexity through modular organization
Solution Approach 2:
A single pad value generator is designed to serve multiple functions by generating synchronized pad values for both write and read channels. This multi-functional approach reduces device complexity by eliminating the need for completely separate pad value generation circuits while maintaining the security requirements of both channels
2Reliability
If synchronized pad values are used for each memory transaction, then encryption reliability is improved, but processing time may increase due to the overhead of maintaining synchronization between separate stream ciphers
Solution Approach 1:
The pad value generator operates continuously to maintain synchronized pad values for both write and read channels. This continuous operation ensures that encryption reliability is preserved without interruption, while the synchronized nature of the generation process minimizes processing overhead by avoiding repeated synchronization operations
Solution Approach 2:
A control mechanism acts as an intermediary to coordinate pad value generation between the write and read stream ciphers. This intermediary ensures that pad values remain synchronized across both channels, maintaining encryption reliability while optimizing processing time through coordinated operation
Data Source
AI summary
Described are systems and method for protecting data and instructions shared over a memory bus and stored in memory. Independent and separately timed stream ciphers for write and read channels allow timing variations between write and read transactions. Data and instructions can be separately encrypted prior to channel encryption to further secure the information. pad generators and related cryptographic circuits are shared for read and write data, and to secure addresses. The cryptographic circuits can support variable data widths, and in some embodiments memory devices incorporate security circuitry that can implement a shared-key algorithm using repurposed memory circuitry.