Block Encryption Integrity Verification via XOR Checking Vector
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Solution Overview
Problem
Symmetric encryption/decryption methods fail to ensure integrity and source authentication, leading to potential tampering of encrypted files, which compromises the security of network communications.
Innovation Solution
A block encryption method that involves generating input blocks by performing XOR operations on message blocks and previous encrypted blocks, followed by encryption and decryption, with a checking vector added to detect tampering and ensure integrity verification without requiring a separate message authentication code operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If symmetric encryption/decryption method is used, then confidentiality is satisfied, but integrity and source authentication cannot be ensured
Solution Approach 1:
The patent merges the confidentiality function (symmetric encryption) and integrity verification function into a single unified mechanism. By incorporating the checking vector generation directly into the encryption process and using the same decryption process for both decryption and integrity verification, the system achieves both confidentiality and integrity without requiring separate independent mechanisms, thus resolving the contradiction between reliability improvement and complexity increase.
Solution Approach 2:
The decryption mechanism is designed to serve multiple functions: it decrypts the encrypted data to recover the original message and simultaneously verifies the integrity of the data through the checking vector. This multi-functional design allows the same process to achieve both confidentiality (by decrypting) and integrity authentication (by verifying), eliminating the need for separate dedicated mechanisms.
2Reliability
If message authentication code operation is added, then integrity verification is achieved, but computational overhead increases
Solution Approach 1:
The patent combines the integrity verification computation with the decryption computation. The checking vector is generated as part of the decryption process using the same key and algorithm, rather than being computed separately as a traditional message authentication code. This merging eliminates redundant computations and achieves integrity verification without additional computational overhead beyond what is already required for decryption.
Solution Approach 2:
The encryption mechanism itself generates the checking vector as an inherent part of its operation, rather than relying on a separate external authentication mechanism. The decryption process uses the same key to both decrypt the message and generate the expected checking vector for comparison, making the system self-sufficient for integrity verification without requiring additional authentication codes or separate computational processes.
Data Source
AI summary
An encryption method and decryption method are provided. The encryption method divides an electronic file into a plurality of message blocks, wherein the message blocks have a sequence. The encryption method sets a checking vector as the last message block. The encryption method performs the following steps on each message block according to the sequence: generating an input block, deriving an output block by encrypting the input block by an encryption key, and deriving an encrypted block by applying XOR operation to the output block and the previous message block, wherein the input block is equivalent to applying XOR operation to the message block, the output block corresponding to the previous message block, and the message block before the previous one. The encryption method generates an electronic encrypted file by concatenating the encrypted blocks. The decryption method performs a series of operations corresponding to the above operations.