Bidirectional Difference Propagation Encryption Method
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing encryption methods face inefficiencies in memory and computational resources due to the need for multiple passes over data blocks for both encryption and decryption, particularly when achieving Bidirectional Difference Propagation (BDP), which is crucial for secure encryption of data packets with varying payloads.
Innovation Solution
A method that preprocesses digital data by performing linear algebra operations on a sequence of blocks, followed by a single pass of encryption using a block cipher in chaining mode, allowing for efficient encryption and decryption with reduced memory requirements, where each ciphertext block depends on all plaintext blocks, ensuring BDP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bidirectional difference propagation is achieved using traditional methods (two processing passes), then security is improved, but memory requirements and computational complexity increase
Solution Approach 1:
The patent applies preliminary action by performing the reverse pass transformation during the encryption phase before transmission. This pre-computes the bidirectional dependencies in one direction, so that during decryption only a single forward pass is needed. The preliminary transformation embeds the security requirements into the ciphertext structure itself, eliminating the need for complex two-pass processing during decryption while maintaining BDP security properties.
2Reliability
If bidirectional difference propagation is achieved using traditional methods (two processing passes), then security is improved, but decryption speed decreases
Solution Approach 1:
The patent applies preliminary action by performing the reverse pass transformation during the encryption phase before transmission. This pre-computes the bidirectional dependencies in one direction, so that during decryption only a single forward pass is needed. The preliminary transformation embeds the security requirements into the ciphertext structure itself, eliminating the need for complex two-pass processing during decryption while maintaining BDP security properties.
3Ease of operation
If CBC mode is used for encryption, then error propagation occurs in only one direction, but bidirectional error propagation is needed for security
Solution Approach 1:
The patent applies inversion by reversing the conventional chaining direction for the first pass of transformation. Instead of chaining from block 1 to block N (forward direction), the first pass chains from block N to block 1 (reverse direction). This inverted approach ensures that errors propagate bidirectionally: forward through the decryption pass and backward through the transformation pass, achieving the desired security property while maintaining operational simplicity.
4Reliability
If the whole sequence of blocks is kept in memory for two-pass processing, then BDP is achieved, but memory requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the encryption/decryption process into two distinct phases with different memory requirements. The transformation phase (performed during encryption) processes blocks in reverse order with full sequence awareness, while the cipher phase (performed during both encryption and decryption) processes blocks in forward order with minimal memory footprint. This segmentation allows BDP to be achieved during transformation while keeping ciphering memory requirements low.
Solution Approach 2:
The patent applies preliminary action by performing the reverse pass transformation during the encryption phase before transmission. This pre-computes the bidirectional dependencies in one direction, so that during decryption only a single forward pass is needed. The preliminary transformation embeds the security requirements into the ciphertext structure itself, eliminating the need for complex two-pass processing during decryption while maintaining BDP security properties.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention aims to provide an efficient solution to the problem of encrypting a plaintext of arbitrary length such that all bits of the ciphertext depend on all bits of the plaintext. Therefore any difference between any two plaintexts makes the two ciphertexts look completely different. This property known as Bidirectional Difference Propagation (BDP) gives a desirable security to encryption methods, as it dissimulates the position of plaintext differences to attackers observing their respective ciphertexts. The encryption method includes two passes over a sequence of N input digital data X1,...XN blocks where the first pass executes iterative linear algebraic operations from the last input block XN to the first input block X1 to obtain a sequence of intermediary resulting YN...Y1 blocks. The second pass executes a block ciphering in a chaining mode from the first intermediary resulting Y1 block to the last one YN to obtain a sequence of encrypted output Z1... ZN blocks. The decryption is carried out only in one pass from the first input encrypted Z1 block to the last input encrypted block ZN. The deciphering operations are executed in an iterative loop of inverse linear algebraic operations after deciphering the first input encrypted Z1 block to obtain an output sequence of decrypted X1,...XN blocks.