Social Networks Research Aspects: A Vast and Fast Survey Focused on the Issue of Privacy in Social Network Sites <s> 17-1-2 Protecting Online Information of SNSs <s> In a social network, nodes correspond topeople or other social entities, and edges correspond to social links between them. In an effort to preserve privacy, the practice of anonymization replaces names with meaningless unique identifiers. We describe a family of attacks such that even from a single anonymized copy of a social network, it is possible for an adversary to learn whether edges exist or not between specific targeted pairs of nodes. <s> BIB001 </s> Social Networks Research Aspects: A Vast and Fast Survey Focused on the Issue of Privacy in Social Network Sites <s> 17-1-2 Protecting Online Information of SNSs <s> Online social networks (OSNs) with half a billion users have dramatically raised concerns on privacy leakage. Users, often willingly, share personal identifying information about themselves, but do not have a clear idea of who accesses their private information or what portion of it really needs to be accessed. In this study we examine popular OSNs from a viewpoint of characterizing potential privacy leakage. Our study identifies what bits of information are currently being shared, how widely, and what users can do to prevent such sharing. We also examine the role of third-party sites that track OSN users and compare with privacy leakage on popular traditional Web sites. Our long term goal is to identify the narrow set of private information that users really need to share to accomplish specific interactions on OSNs. <s> BIB002 </s> Social Networks Research Aspects: A Vast and Fast Survey Focused on the Issue of Privacy in Social Network Sites <s> 17-1-2 Protecting Online Information of SNSs <s> Now a days, more and more of social network data are being published in one way or other. So, preserving privacy in publishing social network data has become an important concern. With some local knowledge about individuals in a social network, an adversary may attack the privacy of some victims easily. Most of the work done so far towards privacy preservation can deal with relational data only. However, Bin Zhou and Jian Pei [11] proposed a scheme for anonymization of social networks, which is an initiative in this direction and provides a partial solution to this problem. In fact, their algorithm cannot handle the situations in which an adversary has knowledge about vertices in the second or higher hops of a vertex, in addition to its immediate neighbors. In this paper, we propose a modification to their algorithm for the network anonymization which can handle such situations. In doing so, we use an algorithm for graph isomorphism based on adjacency matrix instead of their approach using DFS technique [11]. More importantly, the time complexity of our algorithm is less than that of Zhou and Pei. <s> BIB003
Let's assume that we have given all of the helpful information to users to properly manage their information publishing and protecting their privacy. Besides that we have provided them with best tools for adjusting their privacy settings in a fast, accurate, and simple way. Is it the time to relax and feel like we have done all we could do, or there are other issues that we should take care of and study about? The problem is that some of those who are interested in having users' information do not give up and try to exploit from any possible way (sometimes legal and sometimes illegal) to acquire their desired information. In addition to studies that have been done towards directly helping users, it is necessary to make some efforts to keep the online information out of undesired reach. In this part we will take a look at this issue. A study on five Russian SNSs BIB002 shows that despite more concerned users, there is a significant gap between their providers and western SNS Providers about understanding the privacy related concepts and preparing appropriate defencive mechanisms; and overall the privacy condition is reported to be catastrophic that leads to exposure of a large amount of users' information. An important tool that is used to acquire the online information of SNSs is a bot, with which intruders are able to accomplish their actions automatically and with a large scale. Among the actions that could be done with these automatic systems are: crawling, creating fake profiles, and sending forged friendship requests. Obviously something needs to be done to stop these systems. In fact SNS providers should somehow determine whether the requests are sent by a real person or by an automatic system. One thing that could be done is to monitor IP addresses. Another method that is common for online automatic activity detection is using CAPTCHAs [http://www.captcha.net, 47]. A CAPTCHA is a program that protects websites against bots by creating tests that human can pass but programs cannot [http://www.captcha.net]. According to BIB001 , facebook uses an adoption of reCAPTCHA (a related reference is cited) solution which is developed at Carnegie Mellon university. Automatic systems may have mechanisms to pass CAPTCHAs. Also they can exploit the possibility of changing CAPTCHAs that some websites offer, to find a CAPTCHA which they are able to pass. To deal with this, the rate of presented CAPTCHAs could be limited. BIB001 In BIB002 it is concluded that most Russian SNSs do not prevent automatic profile crawling appropriately. Also according to BIB001 in some cases there is a lot of improvement possibility to make CAPTCHAs more difficult to break, and not every SNSs try enough to make automatic crawling and access more difficult. Another way of prevention and detection of suspicious activities is using behavior based anomaly detection techniques that can reduce the speed of the attack and its economical feasibility BIB001 . Although SNSs should try to protect the privacy of users and keep their information accessible only in the way that they have determined by their settings, however there may be some privacy breaches. In BIB001 an interesting example is mentioned. It is said that according to similar characteristics of SNSs, an extendable model could be built and potential breaches could be detected by formal analysis of this model. Changing the structure of services may help to increase the privacy protection level for users. For example in [67] extending link types is mentioned as a helpful action for privacy protection. It means instead of simply just being connected or not connected, people could for example specify the direction of their connection or the amount of trust which exists in the relationship. An example of its benefit is when a malicious user succeeds to fool another user and establish a connection with her. In this situation using trust degree can decrease the consequences of this connection. [67] A kind of extended link types is recently adopted by google's SNS [http://plus.google.com]. In BIB003 and [60] using cryptographic techniques is proposed to prove privacy violations, that can prevent unauthorized access, and if happened compensate or decrease the damage.