Sponge Construction for Secure Data Bus Transmission
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Solution Overview
Problem
Existing cryptographic methods for secure data transmission over a data bus are inefficient for processing small data packets and require separate steps for encryption and authenticity, which can be vulnerable to attacks.
Innovation Solution
A method using sponge constructions to divide data into blocks, encrypt, and sign them, allowing for efficient transmission of encrypted and signed blocks over a data bus, with a duplex sponge construction that alternates between absorption and squeezing phases, utilizing a secret key for confidentiality and authenticity, and leveraging AES operations for encryption and signature generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cryptographic methods (AES-CMAC) are used for data encryption and signing, then security is provided, but the number of AES operations increases significantly (2n+3 operations for n data blocks)
Solution Approach 1:
The patent combines encryption and authentication functions into a single cryptographic hash function based on sponge construction. The sponge function processes data blocks through absorption phases while maintaining internal state, producing both encrypted output and authentication tags simultaneously, thereby reducing the total number of AES operations from 2n+3 to a more efficient count.
Solution Approach 2:
The sponge construction serves multiple cryptographic purposes simultaneously: it provides data encryption, authentication, and integrity verification through a single unified structure. The same sponge function with appropriate parameters can operate in different modes to achieve encryption, MAC generation, or both together, eliminating the need for separate encryption and signing passes.
2Reliability
If separate encryption and signing steps are performed, then authenticity and confidentiality are ensured, but the processing time and complexity increase
Solution Approach 1:
The patent merges the previously separate encryption and signing operations into a single integrated sponge construction process. Data blocks are processed through the sponge function which simultaneously produces encrypted output and authentication tags in one pass, eliminating the sequential overhead of separate operations.
Solution Approach 2:
The sponge construction maintains an internal state that is continuously updated during the absorption phase. This internal state serves as preliminary authentication material that is built up incrementally as data is processed, allowing the authentication tag to be generated efficiently without requiring a separate signing pass after encryption.
3Stability of the object's composition
If explicit synchronization is used for cryptographic operations, then consistency is maintained, but bus utilization decreases and security is compromised
Solution Approach 1:
The sponge construction is self-synchronizing through its internal state mechanism. Each processing step updates the internal state in a deterministic manner, and the same initial state and processing sequence automatically ensure consistency across sender and receiver without requiring external synchronization signals. This eliminates synchronization-related security vulnerabilities.
Solution Approach 2:
The patent extracts the synchronization function from the communication protocol and embeds it within the cryptographic sponge construction itself. The internal state of the sponge function carries the synchronization information implicitly through its deterministic updates, removing the need for separate synchronization mechanisms that could be targeted by attacks.
4Reliability
If small data packets are encrypted using conventional methods, then security is provided, but the overhead becomes significant compared to large data packets
Solution Approach 1:
The sponge construction provides a unified cryptographic primitive that handles data packets of any size efficiently. Whether processing a single small data block or multiple large blocks, the same absorption-extraction mechanism applies, avoiding the overhead issues of conventional methods that are optimized for large packet batches.
Solution Approach 2:
The sponge construction naturally segments data into blocks that are processed through absorption phases, with the internal state carrying forward authentication information. This block-based processing with state persistence allows efficient handling of small packets by maintaining cryptographic context across blocks without requiring separate operations for each packet.
Data Source
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AI summary
Disclosed is a method for safeguarding the information security of data transmitted via a data bus, in which method the data to be transmitted by a transmitter (ECUS) to at least one receiver (ECUR) via the data bus is divided into data blocks (M0... Mn) prior to sending, wherein the data blocks (M0... Mn) are encoded and/or signed in blocks by means of a sponge construction for forming a cryptologic hash function, in conjunction with a key, and cipher blocks (C0... Cn) generated in this manner are transmitted to the at least one receiver via the data bus. The invention also relates to a corresponding data bus system.