Cipher Processing Unit Mask Value Generation
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Solution Overview
Problem
In XTS-AES encryption, generating an initial mask value delays the start of cipher processing, and adding a circuit for this purpose increases the circuit scale, making it difficult to enhance speed.
Innovation Solution
An information processing apparatus with multiple cipher processing units performs encryption or decryption in a block order, where one unit generates an initial mask value for each data unit, allowing the process to start without a dedicated circuit for mask value generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a dedicated cipher processing circuit is added to generate the initial mask value, then the cipher processing speed is improved, but the circuit scale increases
Solution Approach 1:
The patent makes the first cipher processing unit perform multiple functions: it processes both the initial mask value generation and the actual cipher blocks. This multi-functional approach eliminates the need for a dedicated initial mask generation circuit, resolving the contradiction between improving processing speed and maintaining circuit scale.
Solution Approach 2:
The patent merges the initial mask value generation function into the existing first cipher processing unit. By combining these two functions into a single circuit, the patent avoids increasing the overall circuit scale while still enabling parallel processing to improve speed.
2Reliability
If the initial mask value is generated before cipher processing starts, then the cipher processing can proceed correctly, but the start of cipher processing is delayed
Solution Approach 1:
The patent prepares the initial mask value in advance by having the first cipher processing unit generate it before the cipher processing of actual data blocks begins. This preliminary action ensures that when the data processing starts, the initial mask value is already ready, maintaining correctness while minimizing delay through parallel preparation.
Solution Approach 2:
The patent maintains continuous useful action by having the first cipher processing unit continuously work on generating the initial mask value while other units prepare for data processing. This continuous preparation ensures that no time is wasted waiting for mask value generation once the processing pipeline is established.
3Device complexity
If the circuit scale is limited, then the device remains compact, but it becomes difficult to increase processing speed
Solution Approach 1:
The patent segments the cipher processing into multiple independent processing units that can operate in parallel. By dividing the work across multiple units (with the first unit handling mask generation and subsequent units handling data blocks), the system achieves higher throughput without requiring a single large complex circuit.
Solution Approach 2:
The first cipher processing unit is designed to be multi-functional, handling both initial mask value generation and cipher block processing. This universality allows the system to maintain a compact circuit scale while achieving high processing speeds through efficient resource utilization and parallel operation of multiple units.
Data Source
AI summary
A plural number M (M≧2) of block cipher encryption units perform, in a block order, either encryption processing or decryption processing for data of a series of blocks each having a predetermined data size and included in a data unit. The plural number of block cipher encryption units perform either encryption of decryption for the data unit by repeating processing in the block order. Every time processing of a data unit starts, a block cipher encryption unit configured to process the data of the nMth (nM<N, N represents a block count) block in nth (n≧1) processing generates an initial mask value to be used for the encryption or decryption.