System Security Design and Implementation

Data Source

First, 130000 Ethereum transactions were crawled from Etherscan, of which 100000 transactions were used as the training set, 15000 transactions as the verification set, and the remaining 15000 transactions as the test set. The web3.js tool is used to view and deploy transactions. The programming language used in the experiment is Python 3.7.

Transaction attributes of the training set.

Attribute name	Illustrate
fromAddrcss	Account address (sender)
toAddrcss	Account address (receiver)
gasPricc	Gas price
gasLimit	Gas limit
inputDatalf	Whether the inputData field contains data
cvcntDatalf	Whether the event field contains data
contractIf	Whether it is represented as a contract transaction

System Test

Since the automatic coding network is used to embed and retrieve information, the generated secret transactions may not be successfully sent to the blockchain. If the generated secret transaction cannot be deployed, Alice can reset the transaction attributes and merge again. In addition, the extracted secret information does not have to be the same as the original information, so it is necessary to calculate the success rate of embedding and extracting secret information. The average embedding capacity of 100000 transactions and the corresponding embedding success rate and extraction success rate.

Embedded capacity	Embedding success rate	Extraction success rate
1 bytc/T	0.99	0.99
4 bytc/T	0.98	0.98
8 bytc/T	0.96	0.94
12 bytc/T	0.87	0.74

The unit of embedded capacity is the embedded byte size of each transaction. The embedding success rate is the percentage of 100000 transactions successfully executed. The extraction success rate is the ratio of the number of retrieved correct information bytes to the number of embedded information bytes. It can be seen from Table 3 that with the increase in embedding amount, the success rate of embedding and extracting secret information decreases. Whether it is 4 bytes or 8 bytes of secret information, it has a higher embedding capacity, embedding success rate, and successful extraction rate. If the embedded capacity increases to 10 bytes/t, the success rate of extracting information decreases to 0.81. Therefore, it is best to embed 8 bytes of secret information in each transaction.

System Safety Analysis

Ethereum transactions are deployed directly on the blockchain, so the stability of this scheme is equivalent to the tamper resistance of the blockchain itself. After the training generator and extractor, Alice and Bob must save the trained network model parameter file (pt format). Before the two communicators disclose the stored model parameters, the attacker will not be able to crack the secret information.