Automated Vulnerability Detection of Blockchain Smart Contacts Based on BERT Artificial Intelligent Model

The widespread adoption of blockchain technology has led to the exploration of its numerous applications in various fields.Cryptographic algorithms and smart contracts are critical components of blockchain security.Despite the benefits of virtual currency,vulnerabilities in smart contracts have resulted in substantial losses to users.While researchers have identified these vulnerabilities and developed tools for detecting them,the accuracy of these tools is still far from satisfactory,with high false positive and false negative rates.In this paper,we propose a new method for detecting vulnerabilities in smart contracts using the BERT pre-training model,which can quickly and effectively process and detect smart contracts.More specifically,we preprocess and make symbol substitution in the contract,which can make the pre-training model better obtain contract features.We evaluate our method on four datasets and compare its performance with other deep learning models and vulnerability detection tools,demonstrating its superior accuracy.

Blockchain-Enabled Privacy Protection and Access Control Scheme Towards Sensitive Digital Assets Management

With the growth of requirements for data sharing,a novel business model of digital assets trading has emerged that allows data owners to sell their data for monetary gain.In the distributed ledger of blockchain,however,the privacy of stakeholder's identity and the confidentiality of data content are threatened.Therefore,we proposed a blockchainenabled privacy-preserving and access control scheme to address the above problems.First,the multi-channel mechanism is introduced to provide the privacy protection of distributed ledger inside the channel and achieve coarse-grained access control to digital assets.Then,we use multi-authority attribute-based encryption(MAABE)algorithm to build a fine-grained access control model for data trading in a single channel and describe its instantiation in detail.Security analysis shows that the scheme has IND-CPA secure and can provide privacy protection and collusion resistance.Compared with other schemes,our solution has better performance in privacy protection and access control.The evaluation results demonstrate its effectiveness and practicability.

基于Hadoop的海量安全日志聚类算法研究

大数据环境下,网络安全事件层出不穷,网络安全成为各界关注的热点。安全日志记录着设备运行状态的重要信息,通过对其分析可以实时掌握网络安全态势,可作为事前防护、事后追责的安全审计手段,实现对异常事件的追责与溯源。针对日志审计的重要性并结合数据挖掘在日志分析领域的重要作用,同时针对单机环境下处理海量数据效率相对滞后等问题,文章提出一种基于Hadoop的面向海量安全日志的聚类算法。首先,文章提出了基于最大最小距离(MMD)和均值思想对K-means聚类算法进行改进,克服了传统K-means聚类算法在寻找初始聚类中心随机性的缺陷;其次,为了适应海量数据的有效处理,提高聚类的效率与速度,将改进的K-means聚类算法部署在Map/Reduce上进行迭代计算。实验表明,改进的聚类算法的准确性优于其他典型算法,聚类效果稳定,在集群的性能上具有较好的运行速度和加速比。

Semi-Fragile Audio Watermarking Algorithm in DWT Domain

A novel semi-fragile audio watermarking algorithm in DWT domain is proposed in this paper.This method transforms the original audio into 3-layer wavelet domain and divides approximation wavelet coefficients into many groups.Through computing mean quantization of per group,this algorithm embeds the watermark signal into the average value of the wavelet coefficients.Experimental results show that our semi-fragile audio watermarking algorithm is not only inaudible and robust against various common images processing,but also fragile to malicious modification.Especially,it can detect the tampered regions effectively.

面向异构多链的区块链链上数据隐私保护方案

为解决异构区块链数据隐私安全问题,文章在知识付费应用场景下提出一种支持异构多链的数据隐私保护方案,实现了联盟链上知识分享及公有链上知识付费。方案采用IPFS系统存储知识文件,解决了区块链存储负载过重问题。此外,为避免传统公钥加密机制加密次数多、需多次重复对数据进行加密上链的问题,方案利用代理重加密技术实现参与方之间的数据共享。最后,文章从理论和实验两方面对方案进行了正确性、安全性和性能分析。

基于预言机和零知识证明的区块链数据上链方案

区块链上的数据分为链上数据和链下数据。区块链系统凭借其共识机制和密码学相关技术保障了链上数据的真实性和可靠性,但是对于链下数据却缺乏保障机制。一旦不可信数据源提供的污染数据实现数据上链,将会给基于区块链的信息系统带来严重的数据安全隐患。在基于区块链的碳排放机制应用场景下,提出了一种基于预言机和零知识证明的区块链数据上链方案,通过零知识证明实现在不透露数据源碳排放量具体数值情况下提交碳排放量合规性证明,采用门限签名机制实现多个预言机对同一数据源的可信性评估,进一步提高数据源可信性。实验结果表明,加入零知识证明算法后,虽然运行效率降低,但极大地增强了数据的隐私安全性,在数据可用不可见的前提下,保证了数据的可用性。

A New Sequential Digital Multi-Signature Scheme

The paper proposes a new sequential digital multi-signature scheme based on Knapsack public-key cryptosystem,which is different from the existing scheme.The advantages of this scheme over the existing schemes are that it simplifies the signature generation process and speeds up the signature verification process.What’s more,the scheme reduces the cost of communication and redundancy operation, and improves efficiency,and can avoid cheating by signer efficiently,so the scheme has very broad application prospects.

Proof of retrievability based on LDPC codes

In order to reduce the computational overhead of proof of retrievability（POR） scheme, a new POR scheme based on low-density parity-check（LDPC） codes is proposed, noted as LDPC-POR. In the model of PORs scheme, the client preprocesses the data and sends it to an untrusted server for storage, only keeping some metadata. Then, the client sends a challenge to the server to prove that the data stored at the server has neither been tampered nor deleted. In the setup phase of this scheme, the client uses LDPC code to encode the data, and blinds data with permutation and pseudo-random stream. In the challenge phase, the server generates the proof completely based on exclusive OR（XOR）, after that the client makes use of the LDPC code to prove the validity of proof. The theoretical analysis shows that this scheme not only reduces the computational overhead, but also saves storage space compared with the classical scheme. In the meantime security proof is also provided in this paper showing that this scheme is feasible.