National Commission calls for increased CIA,NSA, FBI powers

On June 5, 2000, the National Commission on Terrorism, established by Congress in 1999, released its final report entitled ‘Countering The Changing Threat Of International Terrorism’. Among other recommendations, the Commission calls for increased powers for the FBI and NSA to conduct electronic eavesdropping. Specifically, the Commission wants streamlined procedures for FBI surveillance requests to be presented to the Foreign Intelligence Surveillance Court (FISC). Currently, the Department of Justice Office of Intelligence Policy and Review (OIPR) requires, in addition to probable cause, evidence of wrongdoing or specific knowledge of a political group’s terrorist intentions before forwarding a surveillance application to the FISC. Also, the commission wants past activities of a political group to be considered when determining whether the probable cause threshold is met.     

双系统加密技术下带通配符的基于身份加密方案

带通配符的基于身份加密方案(WIBE)大多存在以下缺陷:a)仅达到选择身份(selective-ID)安全,安全系数较低;b)其私钥或密文长度随身份级数呈线性递增,需要耗费大量的存储空间。针对上述问题,运用Waters的双系统加密技术,在Lewko-HIBE方案的基础上提出了一个密文长度固定的带通配符的分级加密方案。新方案结构紧凑,密钥和密文长度均为常数,加/解密运算速度快,减小了存储空间并提高了计算效率。新方案在标准模型下是适应性选择身份(adaptive-ID)安全的,也叫完全安全,安全级别较选择身份安全更高,并且其安全性可归约为三个静态假设。     

A Parallel Algorithm for determining the inverse of a matrix for use in blockcipher encryption/decryption

In the current world that we live in, of rapid growing technology, and especially reliance on the Internet for our daily lively hood (Banking, shopping, entertainment, news), and also with current crimes (Identity-theft, hacking, spyware), computer security is becoming more and more important. By “computer security” we often refer to addressing three important aspects of a computer-related system: Confidentiality, integrity, and availability. Encryption clearly addresses the need for confidentiality of data, both in storage and transmission. However, the use of encryption can be cumbersome and time consuming. It is important to have a fast algorithm to both encrypt and decrypt data as needed. Public key encryption, though secure, is definitely not fast enough to be used for large size data. We introduce a Parallel Algorithm for computation of inverses of matrices modulo n. This is used in conjunction with Block Ciphers and Hill Ciphers in symmetric encryption and decryption of data for transmission on open lines. Experimental studies were done to compare the run-time of this algorithm on parallel machines, to the traditional one. The new algorithm was found to perform much better than the traditional one, and would be useful to use in encryption/decryption of large sensitive data.

Battle for control of encryption technology

The two sides in the conflict for encryption control are described. In the first camp are law-enforcement and intelligence agencies-the National Security Agency and the FBI-who wish to use wire surveillance as a tool to combat crime, primarily narcotics, but also industrial espionage and anything that threatens national security. In the second camp are the computer and telephone companies that must comply with any new legal requirements. Efforts to stop the widespread use of encryption dating back to the 1970s, when expertise in encryption expanded beyond US intelligence agencies and law-enforcement agencies began to see the need to assert their control of public encryption, are discussed. Current legislative and administrative efforts to limit further advances in encryption technology are also discussed     

Subspace-based technique for speech encryption

The use of signal processing techniques in cryptographic field is an attractive approach in recent years. As an example, the intractability of the under-determined blind source separation (BSS) problem has been used for the proposal of BSS-based speech encryption. However, some weaknesses of this proposal from a cryptographic point of view have been recently published. In this paper, we propose a new encryption method that bypass these weaknesses. The proposed approach is based on the subspace concept together with the use of nonlinear functions and key signals. An interesting feature of the proposed technique is that only a part of the secret key parameters used during encryption is necessary for decryption. Furthermore, if no plain-text is fed to the encryption algorithm, the latter will provide no contents. Analysis results show that the proposed method significantly enhances the security level of existing BSS-based speech encryption methods.     

Performance study of selective encryption in comparison to full encryption for still visual images

Securing digital images is becoming an important concern in today＇s information security due to the extensive use of secure images that are either transmitted over a network or stored on disks. Image encryption is the most effective way to fulfil confidentiality and protect the privacy of images. Nevertheless, owing to the large size and complex structure of digital images, the computational overhead and processing time needed to carry out full image encryption prove to be limiting factors that inhibit it of being used more heavily in real time. To solve this problem, many recent studies use the selective encryption approach to encrypt significant parts of images with a hope to reduce the eneryption overhead. However, it is necessary to realistically evaluate its performance compared to full encryption. In this paper, we study the performance and efficiency of image segmentation methods used in the selective encryption approach, such as edges and face detection methods, in determining the most important parts of visual images. Experiments were performed to analyse the computational results obtained by selective image encryption compared to full image encryption using symmetric encryption algorithms. Experiment results have proven that the selective encryption approach based on edge and face detection can significantly reduce the time of encrypting still visual images as compared to full encryption. Thus, this approach can be considered a good alternative in the implementation of real-time applications that require adequate security levels.     

VoIP encryption module for securing privacy

A VoIP encryption module was designed to prevent eavesdropping on Internet telephones communications and involved encoding/decoding the output data at the transmitter and receiver of the Internet telephone. To reduce the voice delay, a 128 bit AES was used and an RSA algorithm for an asymmetric encoding system was used during the key exchange, which is the first process of the encryption system operation. In order to test the speech quality in the encryption system, a Mean Opinion Score (MOS) value and R-value (E Model) Score were measured and resulted in values of 4.18~4.20 (Good) and 91.77~92.92 (Good), respectively.     

多授权机构下可撤销叛徒的属性基加密方案

针对单授权机构下属性基加密方案中的密钥滥用问题,以及加密机制本身存在的效率和安全问题,研究一种在多授权机构下可对非法用户（或叛徒）进行撤销的属性基加密方案。在单授权机构下属性基加密方案的基础上,利用双线性映射和线性秘密共享方案等来实现多个授权机构相互协作而不需要中央机构控制,并结合完全子树架构将用户映射到二叉树上来提高撤销叛徒的效率,将单授权方案转化成多授权机构下的可撤销叛徒的属性基加密方案MA-TRABE,还分析了该方案的抗串谋攻击安全性和多授权机构下的安全性。根据电子商务安全支付的需要,设计了MA-TRABE的实际应用。     

二维化信息的三维化加密算法研究

根据象棋的博弈原理而整理出一个全新的信息加密算法。在信息加密前,对所有可能用到的原始信息进行二维化处理,建立原始信息表。在信息加密时,找出明文在原始信息表中对应二维坐标的分量信息,再将这些二维信息按一定的规则对应存放在一个三维化表格中而形成密文。解密则按加密时信息存放的顺序取出信息即可。该算法建立了两套完全独立的密钥方案。在7进制数描述原始信息表的背景下,以7×7×2三维表格为例,将信息数字化二维处理,实验结果表明,该算法计算量少,速度较快,安全性高,得到的密钥数量多。