Data Word Encoding With Chained Parity Error Detection
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Solution Overview
Problem
Existing data transmission methods in security-critical applications, such as chip card controllers, face challenges in detecting unauthorized manipulations and errors with high probability, particularly since single parity bits only offer 50% error detection probability, which is inadequate for secure data protection.
Innovation Solution
The method involves computing a parity code for each data word and altering it based on the preceding data word, ensuring that errors or manipulations can be detected securely by propagating discrepancies through subsequent data transmissions, using a single parity bit and a function like XOR operation to modify the data words, guaranteeing 100% error detection after a predetermined number of transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single parity bit is used for error detection, then the data transmission overhead is minimized (only 1 bit added), but the error detection probability is limited to 50%
Solution Approach 1:
The patent applies preliminary action by modifying each data word before transmission using the XOR operation with the previous data word. This preprocessing step embeds error propagation capability into the data stream, so that a single parity bit can detect errors with higher probability. The modification is performed in advance (before transmission) and creates a dependency chain that amplifies error detection capability without adding multiple parity bits.
2Reliability
If further parity bits are added to raise error detection probability, then the reliability of error detection improves, but the amount of data to be transmitted increases
Solution Approach 1:
The patent changes the parameter of data word representation by applying the XOR operation with the previous data word. This transformation modifies the data in a way that propagates errors through the sequence, allowing a single parity bit to detect a broader range of error patterns. Instead of adding more parity bits (increasing overhead), the patent changes the parameter of how data is encoded to achieve better error detection with the same overhead.
3Productivity
If data words are transmitted without modification, then the transmission process is simple and fast, but errors or manipulations cannot be reliably detected in subsequent transmissions
Solution Approach 1:
The patent implements feedback by using the previous data word to modify the current data word through XOR operation. This creates a feedback loop where each data word carries information about its predecessor, establishing a chain of dependency. If an error occurs in any data word, it propagates through the sequence and can be detected by the parity check. The feedback mechanism maintains transmission speed while significantly improving error detection capability.
Data Source
AI summary
The invention relates to a method for encoding digital data, in particular of data processed in a microprocessor unit. In the method according to the invention for a respective data word (A, B, C) of a series of data words to be encoded subsequently a parity code (P(A), P(B), P(C)) is computed on the basis of the data of the respective data word (A, B, C). Further the respective data word (A, B, C) is altered with the aid of the data word (A, B, C) preceding it in the series, wherein the altered data word (Aa, Ba, Ca) and the parity code (P(A), P(B), P(C)) represent the encoded data word (Ac, Bc, Cc) and the encoded data word (Ac, Bc, Cc) can be decoded with the aid of the data word (A, B, C) preceding it in the series.