Plaintext Integrity Protection via Parallel Authentication Tags
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Solution Overview
Problem
Existing link encryption techniques, such as AES-GCM, provide integrity protection only for encrypted data (ciphertext) and do not guarantee the integrity of decrypted plaintext in the presence of faults, nor do they have reserved space for additional plaintext authentication information.
Innovation Solution
A plaintext integrity protection mechanism that generates additional authentication tags for plaintext, computed in parallel with the encryption or decryption of ciphertext, and combines these with existing ciphertext authentication tags to create a combined authentication tag compatible with existing standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AES-GCM is used for link encryption, then confidentiality and integrity of ciphertext are ensured, but integrity of plaintext is not guaranteed in the presence of faults
Solution Approach 1:
The patent combines plaintext authentication tag generation with the existing AES-GCM encryption process by integrating a parallel GHASH computation path. The plaintext authentication tag is generated simultaneously with the ciphertext authentication tag during the same encryption operation, merging two authentication functions into a unified cryptographic primitive that maintains plaintext integrity without requiring separate authentication mechanisms.
Solution Approach 2:
The patent performs plaintext authentication tag generation in parallel with the encryption process, computing the authentication tag over the plaintext before encryption occurs. This preliminary authentication computation ensures that any faults introduced during encryption can be detected by comparing the expected plaintext authentication tag with the computed one, providing proactive integrity protection rather than reactive verification.
2Reliability
If additional plaintext authentication information is transmitted, then plaintext integrity protection is enhanced, but link protocol compatibility is compromised
Solution Approach 1:
The patent merges the plaintext authentication tag with the existing ciphertext authentication tag from AES-GCM into a single combined authentication structure. By integrating both authentication tags into the existing protocol framework and using them jointly for verification, the system enhances plaintext integrity protection without requiring separate transmission channels or modifying the established link protocol message formats.
Solution Approach 2:
The patent creates a multi-functional authentication mechanism where the same cryptographic primitive serves dual purposes: protecting ciphertext integrity (original AES-GCM function) and protecting plaintext integrity (newly added function). The authentication tags generated by this universal mechanism can verify both encrypted and decrypted data, allowing a single protocol extension to provide comprehensive integrity protection across multiple security boundaries.
3Productivity
If plaintext authentication tag generation is performed in parallel with encryption, then processing efficiency is maintained, but computational complexity increases
Solution Approach 1:
The patent segments the authentication tag generation into two independent parallel paths: one path computes the authentication tag over the plaintext using a first key, and another path computes the authentication tag over the ciphertext using a second key. This segmentation allows both computations to proceed simultaneously without interfering with each other, maintaining encryption processing efficiency while distributing the computational workload across separate circuit modules that can operate in parallel.
Solution Approach 2:
The patent introduces an intermediary GHASH computation mechanism that mediates between the plaintext/ciphertext and the authentication key. Rather than implementing complex custom authentication functions, the system uses the standardized GHASH operation as an intermediary that can efficiently process both plaintext and ciphertext authentication in parallel, leveraging existing cryptographic hardware accelerators and maintaining compatibility with established AES-GCM implementations.
Data Source
AI summary
An apparatus is described including cryptography circuitry to generate authentication tags to provide integrity protection for plaintext and ciphertext.