Keyed Cryptographic Checksum for Secure CRC Authentication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cryptographic checksum methods, such as traditional CRCs, are resource-intensive and inadequate for constrained devices like M2M and IoT, and lack formal security proofs, while also being vulnerable to malicious errors.
Innovation Solution
A cryptographic checksum method using a generator polynomial of the form (1−x)·p1(x), where p1(x) is a primitive polynomial of degree n−1, selected based on a cryptographic key, to provide secure integrity assurance and detect double-bit errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If keyed cryptographic hash functions (HMAC, CBC-MAC) are used for user plane protection, then security and authentication are improved, but resource consumption increases and device complexity worsens
Solution Approach 1:
The patent changes the parameter of the hash function by using a cryptographic checksum function with a specifically designed generator polynomial that has properties (primitive polynomial factors) providing both security and efficiency. This parameter change allows the function to operate more efficiently on constrained devices while maintaining security properties.
Solution Approach 2:
The patent employs a disposable cryptographic checksum approach where a new checksum is generated for each message using a lightweight algorithm. This avoids the need for complex, persistent cryptographic state management while providing fresh security validation for each transmission, suitable for resource-constrained IoT devices.
2Reliability
If keyed cryptographic hash functions are used, then authentication is improved, but message length increases and power consumption worsens
Solution Approach 1:
The patent extracts only the essential authentication functionality from complex cryptographic hash functions, implementing a streamlined checksum generation that produces compact validation data. This extraction removes unnecessary computational overhead while retaining the core authentication capability, reducing both message overhead and power consumption.
3Productivity
If traditional CRC codes are used for error detection, then resource efficiency is improved, but security against malicious errors worsens
Solution Approach 1:
The patent creates a composite cryptographic checksum function that combines the structural efficiency of CRC-like algorithms with the security properties of cryptographic hash functions. The generator polynomial incorporates primitive polynomial factors that provide both the mathematical structure needed for efficient computation and the cryptographic properties needed for security against malicious attacks.
Solution Approach 2:
The patent changes the parameters of the checksum algorithm by selecting specific generator polynomials with cryptographic properties (primitive polynomial factors) while maintaining the efficient computational structure of CRC. This parameter optimization allows the system to achieve both resource efficiency and security, unlike traditional CRC which lacks security guarantees.
4Ease of operation
If CRC with fixed generator polynomial is used, then implementation simplicity is improved, but detectability of malicious errors worsens
Solution Approach 1:
The patent introduces dynamics into the checksum system by making the generator polynomial selection variable based on cryptographic keys or message characteristics. Instead of a fixed polynomial, the system dynamically selects from a set of polynomials with primitive factors, maintaining implementation simplicity through pre-computed tables while enhancing malicious error detection capability.
Data Source
AI summary
A method (400) of generating a cryptographic checksum for a message M(x) is provided. The method is performed by a communication device, such as a sender or a receiver, and comprises calculating (405) the cryptographic checksum as a first function g of a division of a second function of M(x), ƒ(M(x)), modulo a generator polynomial p(x) of degree n, g(ƒ(M(x))mod p(x)). The generator polynomial is calculated (403) as p(x)=(1−x)·P1(x), and P1(x) is a primitive polynomial of degree n−1. The primitive polynomial is selected (402), based on a first cryptographic key, from the set of primitive polynomials of degree n−1 over a Galois Field. By replacing a standard checksum with a cryptographic checksum, an efficient message authentication is provided. The proposed cryptographic checksum may be used for providing integrity assurance on the message, i.e., for detecting random and intentional message changes, with a known level of security. The proposed checksum is capable of detecting double-bit errors which may be introduced by a Turbo code decoder.