Authenticated Encryption Initialization Vector Generation
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Solution Overview
Problem
Existing Authenticated Encryption with Associated Data (AEAD) schemes, such as AES-SIV, fail to prevent the decryption of manipulated associated data from resulting in the original plaintext, as they do not adequately account for changes in the associated data during the decryption process, leading to potential integrity breaches.
Innovation Solution
The proposed method computes an integrity value based on the input data using a first hash function and generates an initialization vector using a second hash function linked to the associated data, ensuring that any manipulation of the associated data results in a different initialization vector, thus preventing the decryption of manipulated data from producing the original plaintext.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AES-SIV authenticated encryption is used with associated data, then integrity protection is provided for encrypted data, but manipulation of associated data can still result in decryption producing the original plaintext
Solution Approach 1:
The patent applies preliminary anti-action by computing an integrity value from the plaintext before encryption and incorporating it into the initialization vector through a hash function. This pre-computed integrity value is then used during decryption to detect any manipulation of associated data before the decryption process completes, preventing the harmful effect of producing original plaintext from manipulated associated data.
Solution Approach 2:
The patent implements feedback by computing a test integrity value from the decrypted plaintext and comparing it with the transmitted integrity value. This feedback mechanism detects whether the associated data was manipulated during transmission, and if so, prevents acceptance of the decrypted plaintext, thereby closing the integrity protection loop.
2Productivity
If associated data is not encrypted but integrity checked, then processing efficiency is improved, but the initialization vector must be carefully linked to associated data to prevent integrity breaches
Solution Approach 1:
The patent merges the integrity value computation and initialization vector generation into a single unified process using a hash function that takes both the integrity value and associated data as inputs. This combining approach maintains processing efficiency by avoiding separate encryption operations on associated data while ensuring the initialization vector is properly linked to associated data integrity.
Solution Approach 2:
The patent introduces a hash function as an intermediary between the integrity value/associated data and the initialization vector. This intermediary component simplifies the relationship by providing a deterministic, efficient transformation that links associated data to the initialization vector without requiring complex cryptographic operations, thereby balancing efficiency and complexity.
Data Source
AI summary
A device is arranged for encrypting input data and protecting integrity of the input data and associated data. An encryption processor has a first hash unit arranged to compute an integrity value based on the input data, a second hash unit arranged to compute an initialization vector based on the integrity value and associated data, producing an initialization vector that is different from the integrity value. At least one of the hash units may be a keyed hash unit. An encryption unit is arranged for encrypting the input data to generate encrypted data using the initialization vector and an encryption key. As the initialization vector depends on both the integrity value and the associated data, any change therein will result in failure of the decryption and decrypted data that are substantially different from the original input data.