Post 4 Social Network Security.

Post 4

Security service is a service, provided by a layer of communicating open systems, which ensures adequate security of the systems or of data transfers as defined by ITU-T X.800 Recommendation. Security service (telecommunication) is the security architecture for the interconnection of open systems. (Wikipedia’s descriptions about Security service (telecommunication) URL: http://en.wikipedia.org/wiki/Security_service_%28telecommunication%29)

The following are considered to be the conventional security objectives / security services.

Authentication services provide for the authentication of a communicating peer entity and the source of data.

Access control service provides protection against unauthorized use of resources accessible via OSI. These may be OSI or non-OSI resources accessed via OSI protocols. This protection service may be applied to various types of access to a resource (e.g., the use of a communications resource; the reading, the writing, or the deletion of an information resource; the execution of a processing resource) or to all accesses to a resource.

Data confidentiality services provide for the protection of data from unauthorized disclosure such as connection confidentiality, selective field confidentiality and traffic flow confidentiality.

Data integrity services counter active threats and may take one of these forms such as connection integrity with recovery, connection integrity without recovery, selective field connection integrity, connectionless integrity and selective field connectionless integrity

Non-repudiation service may take one or both of two forms. The two forms are non-repudiation with proof of origin and non-repudiation with proof of delivery.

(Above refer to OSI Security Services General description of Wikipedia’s descriptions about Security service (telecommunication) URL: http://en.wikipedia.org/wiki/Security_service_%28telecommunication%29)

Three main security objectives are identified in the context of OSNs, they are privacy, integrity and availability.

Privacy in OSNs encompasses user profile privacy, communication privacy, message confidentiality and Information disclosure. In principle, privacy calls for the possibility to hide any information about any user, even to the extent of hiding their participation in the OSN in the first place. Moreover privacy has to be met by default; all information on all users and their actions has to be hidden from any other party internal or external to the system, unless explicitly disclosed by the users themselves. Requiring explicit disclosure leads to the need for access control.

As part of integrity, the user’s identity and data must be protected against unauthorized modification and tampering.

Availability of user profiles is consequently required as a basic feature, even though considering recreational use. In OSNs, this availability specifically has to include robustness against censorship, and the seizure or hijacking of names and other key words. Apart from availability of data access, availability has to be ensured along with message exchange among members.

(Above according to slide 6-10 of week10)

The differences I think between the social network security objectives and that of conventional online networks are below.

1.       Authentication

The authentication of conventional online networks just need username and passwords, sometimes even without E-mail address, but when we register on social network web, we are often asked to provide E-mail, real name, ID NO., education information and employment information and send Verification code via our own mobile phone.

2.       Resources Exchange

In conventional online networks, it protects against unauthorized use of resources accessible via OSI. But In OSNs, this availability specifically has to include robustness against censorship, and the seizure or hijacking of names and other key words. Apart from availability of data access, availability has to be ensured along with message exchange among members.

3.       User’s identity and data

Because the authentication of social network includes some user’s profile, so as part of integrity, the user’s identity and data must be protected against unauthorized modification and tampering. It for conventional online networks is not a must.

4.       Data confidentiality

Data confidentiality services of conventional online networks provide for the protection of data from unauthorized disclosure. But for social networks, the range is much wider, it encompasses user profile privacy, communication privacy, message confidentiality and Information disclosure.

From all of above, it shows the social network needs the higher security level, because it contains more privacy information.

Social Network Analysis (SNA)

Social Network Analysis (SNA) is the study of the pattern of interaction between actors and focuses on the social actor and the relationship between the actors. Social network analysis refers to methods used to analyze social networks, social structures made up of individuals (or organizations) called "nodes", which are tied (connected) by one or more specific types of interdependency, such as web pages, blogs, emails, instant messages, families, journal articles, neighborhoods, classes, sectors within organizations, positions, or nations. Nodes, or network members, are the units that are connected by the relations whose patterns researchers study. The units are most commonly individuals, groups or organizations, but in principle any units that can be connected to other units can be studied as nodes.

The graphical representation (Sociograph) of social network above has five nodes; they are Alice, Bob, Carol, David and Eva. The links (ties) between these five nodes are undirected.Itis one mode networks. This networks can be represented by a simple matrix.

	Alice	Bob	Carol	David	Eva
Alice	–	1	1	1	0
Bob	1	–	0	1	0
Carol	1	0	–	1	0
David	1	1	1	–	1
Eva	0	0	0	1	–

The cutpoint of this networks is node “David”, because if David is deleted, it will make the network disconnected.

The degree of every node is below:

d(nAlice)=3

d(nBob)=2

d(nCarol)=2

d(nDavid)=4

d(nEva)=1

For this undirectional graph, density is

=L/g(g-1)/2=6/5(5-1)/2=0.6

= = =0.6

The geodesic distances between every two nodes are …

d(Alice, Bob)=1

d(Alice, Carol)=1

d(Alice, David)=1

d(Alice, Eva)=2

d(Bob, Carol)=2

d(Bob, David)=1

d(Bob, Eva)=2

d(Carol, David)=1

d(Carol, Eva)=2

d(David, Eva)=1

{Alice, Carol, David} and {Alice, Bob, David} are cliques.

{Alice, Bob, Carol, David, Eva} is a 2-clique.

{Alice, Bob, Carol, David} is a 2-plex.

Within this social network, David is the most influential. Three standard centrality measures will help us to find the most influential; they are degree centrality, closeness centrality and betweenness centrality. Centrality identify which nodes are in the ‘center’ of the network and the “key player”. In a social network, nodes at the center can be very important

Firstly, Degree centrality of this network shows as below. The degree centrality of node “David” is 4, the highest in these five nodes.

Secondly, the closeness centrality below shows the actor “David” is considered the most important, because it is relatively close to all other actors.

Group Degree Centralization

(4-1)+(4-2)+(4-2)+(4-3)/4*3=0.667

The group degree centralization is 0.667.

Group Degree Closeness Centralization

Closeness is based on the inverse of the geodesic distance of each actor to every other actor, therefore the shorter the distance is, the larger the closeness will be.

Alice:0.8

Bob:0.667

Carol:0.667

David:1

Eva:0.57

By using this formula, the group closeness can be calculated out as 0.756.

Group Betweenness Centralization

Alice=1/12

Bob=Carol=Eva=0 

David=7/12

In this social network, the group betweeness centralization is 0.5625.

Therefore,Through the above algorithms results, we can image that  “David” is considered the most important on the social network of these five students .

Post 2 “interactive services and entertainment”

In Lecture 4, firstly, I have revisted social media for further study. Secondly, I have learnt something about Blogs, including the defination of blog and blogosphere, tips for blog writing, professional blog writing. As an online learning environment, four factors of blog contents are aspected, they are cognitive, metacognitive, epistemic cognitive and social. Last, information sharing often achieves by recommendation and reviews, cases study for Social Marketing helps me to understand. In Lecture 5, I have learnt about social multimedia computing, including the interaction and computing, applications, research issues, key challenges.

In the past, I had just learnt the defination of social media in Lecture 1, and in Lecture 5, I have learnt more about social media for further study, for example, characterization of Social Media, social interaction around multimedia, applications, search issues and key challenges. In the past, I thought the blog is just a “diary on the web”, but in Lecture 4, I have re-understood the blog. I have learn some tips for blog writing, ever professional blog writing, I tried to use these tips to make my post better. In the past, I didn’t have the habit to write blog. Would any classmates recommend any well-known blogs? I hope that I can learn more from these famous blogs. Thanks!

In these two lectures, I’m very interested in “interactive services and entertainment”. Interactive service is one of the most promising application areas of social multimedia computing.

Many Apps in iPhone provide the interactive service. The screenshot below shows the App “My Horse” provide the interactive service, you can share your progress on Facebook and Twitter with your friends.

Another example, famous game “Fruit Ninja”, you can connect Game Center, Facebook and Twitter to interact with your friends.

You also can share the vedios on YouTube to Facebook and Twitter. Multimedia applications have become ubiquitous lately. People record and watch videos on mobile and stationary devices, they share and organize their personal multimedia archives. Lots of research has been done on the technical aspects of multimedia, like streaming, presentation, transcoding, adaptation and content based retrieval and analysis. But handling multimedia is an interactive process and users have to be taken into account. Even consumption is often accompanied with communication, browsing and search. This interactivity in multimedia applications is a challenging yet very promising topic as especially in multimedia applications, people more often accept innovative ideas and fundamental changes more easily.

Social media is media for social interaction as a super-set beyond social communication. Enabled by ubiquitously accessible and scalable communication techniques, the interaction of social media has substantially changed the way organizations, communities, and individuals communicate.

social networking post1

The contents that I have ever learnt in lecture 1 is the overview of social networking, mainly include the defination of social media, social computing and social networking, and the relationship between social media and social networking. Something about social computing, from both theoretical and technological perspectives, social computing technologies moves beyond social information processing towards emphasizing social intelligence. In lecture 2, I have learnt the social experience, Cognitive processing and memory, and social nature of human activity. The lectuire 3 makes me to to learn about how our mind is engaged in social networking environments, and how should we design social environments by two facts, one is theory of knowledge and cognition, and the other one is social tasks.

In the past, I thought social networking was the website like Facebook to provide a platform for communication and interactive. From lecture 1 to 3, I have learnt more about social networking. It concerned with the conduction of various social behaviors over the internet, as well as the underlying technologies. It is an interdisciplinary subject involving multiple fields including computer networks and applications, psychology, as well as sociology. This course provides a holistic overview on both technology and humanity aspects of social networks, with emphases on the social sciences aspects and perspectives. It covers topics such as social network analysis (e.g. discourse analysis, semantics, social network structure), network-mediated knowledge building and collaboration, epistemology in social networks, and applications of social networks in business and education. I also want to know something about the business model of social website, besides the advertisement on page, how to earn the money.

When I was in Beijing I can’t log on the Facebook, Twitter and so on, so I registed new accounts on these websites to help my revision. By comparing with these websites, I’ll learn more about social networking.

I’m very interested in “Relationship mapping and mining” of social networking. We often use SNS such as facebook to find our old friend, classmates and so on, map the relationships, establish social interactions in different channels such as email, instant messaging, enterprise databases, etc. that embody shared or social activities among a known set of users who have given their permission. Put simply, social networking is a way for one person to meet up with other people on the Net. That's not all though. Some people use social networking sites for meeting new friends on the Net. Other's use it to find old friends. Then there are those who use it to find people who have the same problems or interests they have.

A networked computer system provides various services for assisting users in locating, and establishing contact relationships with, other users. For example, in one embodiment, users can identify other users based on their affiliations with particular schools or other organizations. The system also provides a mechanism for a user to selectively establish contact relationships or connections with other users, and to grant permissions for such other users to view personal information of the user. The system may also include features for enabling users to identify contacts of their respective contacts. In addition, the system may automatically notify users of personal information updates made by their respective contacts.

There is a very well-known theory. It says that six degrees of separation refers to the idea that everyone is on average approximately six steps away, by way of introduction, from any other person on Earth, so that a chain of, "a friend of a friend" statements can be made, on average, to connect any two people in six steps or fewer. A Facebook platform application named "Six Degrees" was developed by Karl Bunyan, which calculates the degrees of separation between different people. It had over 5.8 million users, as seen from the group's page. The average separation for all users of the application is 5.73 degrees, whereas the maximum degree of separation is 12. The application has a "Search for Connections" window to input any name of a Facebook user, to which it then shows the chain of connections.

Today. More and more relationships and friendships are being formed online. Experts in relationships, such as the German psychologist Erich H. Witte, say that relationships which start online are much more likely to succeed, and he goes on to say that in less than 10 years, online dating will be the most widely used way to get to know someone for a possible relationship.