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E-commerce Security Issues

First of all e-commerce is surrounded by different issues such as commercial, Network infrastructure, Social and Cultural and Security issues are presented below which are important for successful business. E-commerce security issues are frequently aired in the press and are certainly important. Customers are concerned that the item ordered won’t materialize, or be as described. As (much worse) they worry about their social security number and credit card details being misappropriated. However rare, these things do happen, and customers need to be assured that all e-commerce security issues have been covered. Your guarantees and returns policies must be stated on the website and they must be adhered to. Let us first state the security attacks on e-commerce process and Security goals we want to achieve for successful e-commerce.

Attacks on Security
Security attacks can be classified in the following categories depending on the nature of the attacker.

a)      Passive Attacks
The attacker can only eavesdrop or monitor the network traffic. Typically, this is the easiest form of attack and can be performed without difficulty in many networking environments, e.g. broadcast type networks such as Ethernet and wireless networks.

b)      Active Attacks
The attacker is not only able to listen to the transmission but is also able to actively alter or obstruct it. Furthermore, depending on the attackers actions, the following subcategories can be used to cover to cover the majority to cover the majority of attacks.

c)       Eavesdropping
This is attack is used to gain knowledge of the transmitted data. This is passive attack which is easily performed in many networking environments as motioned above. However, this attack can easily perform in many networking environments. However this attack can easily be prevented by using an encryption scheme to protect the transmitted data.

d)      Traffic Analysis
The main goal of this attack is not to gain direct knowledge about the transmitted data, but to extra information from the characteristics of the transmission, e.g. amount of data transmitted, identity of the communicating nodes etc. This information may allow the attacked to deduce sensitive information, e.g., the roes of the communicating nodes, their position etc. Unlike the previously described attack, this one is more difficult to prevent.

e)      Impersonation
Here, the attacker uses the identity of another node to gain unauthorized access to resource or data. This attack is often used as a prerequisite to eavesdropping. By impersonating a legitimate node, the attacker can try to gain access to the encryption key used to protect the transmitted data. Once, this key is known by the attacker, she can successfully perform the eavesdropping attack.

f)       Modification
This attack modifies data during the transmission between the communicating nodes, implying that the communicating nodes do not share the same view of the transmitted data. An example could be when the transmitted data represents a financial transaction where the attacker has modified the transactions value.

g)      Insertion
This attack involves an unauthorized party, who inserts new data claiming that it originates from a legitimate party. This attack is related to that of impersonation.

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Benefits of e-commerce

Use of e-commerce technologies helps speed up the flow of information and to eliminate unnecessary human intervention; the computer can now accomplish what computers do better than people process routine business transactions quickly and accurately, 24 hours a day. This in turn, frees up people to handle tasks that computers may never be able to do exercising judgment, creativity, and experience to manage exceptions, solve problems and continually improve business processes.

E-commerce is growing in importance and means unprecedented opportunities for everyone. When a business takes advantage of the power of e-commerce, it will be able to.

i. Increase customer satisfaction

Internet is always open, even on holidays; business is thus always open, 24 hours a day, 7 days a week and 365 days a year. Customers will appreciate the extra access to product updates, shipping details, billing information and more. And since the internet knows no boundaries, customers can shop from home, work, or anywhere they can make a connection. Besides, by connecting the e-commerce and shipping systems, it would be possible to ship products faster and for less money.

ii. Increase sales volumes

The Internet is a new channel to reach new customers. With a web site, a company can automatically become a global provider of goods and services, with an edge over even the largest competitors. Interactive selling is advantageous because a company is no longer limited by shelf-space or inventory concerns but instead offer all products to suit the customers exact specifications.

iii. Decrease costs of doing business

E-commerce helps cut out or streamline processes that eat away profits. For instance exchange of information from advertising to availability updates, can add to the cost of sale. However, the web site can be an efficient, cost-effective communication vehicle. Customers can find timely accurate information in one place when they need it. By using e-commerce, everything from purchase orders to funds transfer can be handled faster and more efficiently. Even payment processing and bookkeeping are easier.

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Definition of Tree

A tree is a combination of a finite set of elements, called nodes and a finite set of directed lines, called branches that connect the nodes.

The number of branches associated with a node is the degree of the node. When the branch is directed towards the node, it is an indegree branch. When the branch is directed away from the node, it is an out degree branch, the sum of outdegree and indegree branches equal to the degree of the node.

Some important terms:

Root node: If the tree is non empty, then the first node is called as root. The indegree of root by definition is zero.
Leaf node: A node with no successors (nodes after it). There will usually be many leaves in a tree.
Non Leaf node: A node which has both a parent and at least one child.
Internal nodes: Nodes that are not root and not leaf are called as internal nodes
Parent node: A node is a parent if it has successor nodes; means out degree greater than zero.
Child node: A node is child node if indegree is one.
Siblings: Two or more nodes with same parent are siblings.
Ancestor node: An ancestor is any node in the path from the root to the node.
Descendant node: A descendent is any node on the path below the parent node.
Subtree: A subtree is any connected structure below the root.
Directed tree: A directed tree is an acyclic digraph, which has only one node with indegree 0, and others nodes have indegree 1.
Binary tree: A binary tree is a tree in which no node can have more than two subtrees. In other word it is a directed tree in which outdegree of each node is less than or equal to two. (i.e. zero, one or two). An empty tree is also a binary tree.
Strictly binary tree: If the outdegree of every node in a tree is either 0 or 2, then the tree is said to be strictly binary tree. i.e. each node can have maximum two children or empty left and empty right child.
Complete binary tree: A strictly binary tree in which the number of nodes at any level i is 2 i-1 then the tree is said to be complete binary tree.
Almost binary tree: A tree of depth d is an almost complete binary tree, if the tree is complete up to the level d-1.
Tree traversals: Tree traversal is the technique in which each node in the tree is processed or visited exactly once systematically one after the other. The different tree traversal techniques are Inorder, Preorder and Postorder.Algorithm for tree traversal

i) Inorder (Left-Root-Right)

Traverse the left sub tree in inorder [L]
Process the root node [N]
Traverse the right sub tree in inorder [R]

ii) Preorder (Root-Left-Right)

Process the root node [N]
Traverse the left sub tree in preorder [L]
Traverse the right sub tree in Preorder [R]

iii) Postorder (Left-Right-Root)

Traverse the left subtree in post order. [L]
Traverse the Right sub tree in postorder [R]
Process the root node [N]

Binary Search tree: A binary search tree is a binary tree in which for each node say x in the tree elements in the left subtree are less than info(x) and elements in the left subtree are greater or equal to info(x).

The operations performed on binary search tree are:

Insertion: An item is inserted
Searching: Search for a specific item in the tree.
Deletion: Deleting a node from a given tree.

Balanced Search trees: Balanced search tree is on that exhibits a good ratio of breadth to depth. There are special classes of Balanced Search Trees that are self-balancing. That is as new nodes are added or existing nodes are deleted, these Balanced search Trees automatically adjust their topology to maintain an optimal balance. With an ideal balance, the running time for inserts, searches, and deletes even in the worst case is log2n.

AVL trees, Red-Black trees, Lemma are the examples of balanced search trees.

AVL Trees: An AVL tree is a binary search tree whose left subtree and right subtree differ in height by at most 1 unit, and whose left and right trees are also AVL trees.

To maintain balance in a height balanced binary tree, each node will have to keep an additional piece of information that is needed to efficiently maintain balance in the tree after every insert and delete operation has been performed. For an AVL tree, this additional piece of information is called the balance factor and it indicates if the difference in height between the left and right subtrees is the same or, if not, which of the two subtrees has height one unit larger. If a node has a balance factor rh(right high). It indicates that the height of the left subtree. Similarly the balance factor for a node could be lh(left height) or eh(equal height).

Binary Heap tree: A binary heap is a complete binary tree. A tree that is completely filled except possibly at the bottom level, which is filled from left to right with no missing nodes.

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Definition of List and Linked List

List is a generic term for a collection of objects. It may or may not contain duplicates and application may or may not require that it be kept in specified order.

The functions defined to operate on a list are

·         Insert: Insert a new entry into a list
·         Delete: Delete an entry from list
·         Length: Compute length of a list
·         Next: Return the next element in a list
·         Search: Search if an element is in a list

Linear list: A linear list is a sequence of n>=0 nodes x[1], x[2], x[3] ……………x[n] whose essential structural properties between items as they appear in a line.

Restricted list: In restricted list, Data can only be added or deleted at the ends of a structure and processing is restricted to operations at the end of lists.

The two restricted list structures are First In First Out (FIFO) stacks and Last In First Out (LIFO) queue.

The four operations performed on linear lists are

i.            Insertion
ii.            Deletion
  iii.            Retrieval
iv.            Traversal

Depending on the type of linear list, an insertion can be made at the beginning of the list, or at the end of the lists. When inserting data into ordered list, the data must be inserted so that the ordering is maintained. Deletion from general lists requires that the list be searched for the data to be deleted.

List retrieval requires that data be located in a list and presented to the calling module without changing the contents of the lists.

List traversal is a special case of retrieval in which all the elements are retrieved in a sequence.

Definition of Linked list

A link list is a collection of records, called nodes, each containing at least one field(member) that gives the location of the next node contains two members; a data member (the value of the list item) and a link member (a value locating the next node).The link list is a very flexible dynamic data structure. It is a low-level structure upon which high-level data structures can be built.

The Typical basic linked-list operations are

i.            Create: Makes a new linked list
ii.            Insert: Puts a new node in its place in the list.
  iii.            Remove: Remove a node from the list.
iv.            Traverse: This function allow user to visit each node in the list.
v.            Is empty: The function returns a true/false indication of whether or not there are any nodes in the list.
vi.            Is full: This function returns a true/false indication of whether or not the list is full

Types of linked lists

i.            Singly linked lists
ii.            Circular singly linked lists
  iii.            Doubly linked lists
iv.            Circular Doubly linked lists

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Definition of Queues

A queue is defined as a special type of data structure where elements are inserted from one end and elements are deleted from other end.

The end from where the elements are inserted is called rear end (r) and the end from where elements are deleted called front end (f). In a queue always elements are inserted from the rear end and elements are deleted from the front end.

Queue is a linear list for which all insertions are made at the end of the list; all deletions (and usually all accesses) are made at the other end. So queue is also called First in First out (FIFO) data.

Different types of queues

Ordinary queue
Double ended queue
Circular queue
Priority queue

1. Ordinary queue

This queue operates on the first come first serve basis. Items will be inserted from one end and they are deleted at the other end in the same order in which they are inserted. A queue can be represented by using an array by using an array as shown in the figure.

The operations that can be performed on these queues are

Insert an item at the rear end
Delete an item from the front end
Display the contents of the queue

Disadvantage of Ordinary queue

2. Double ended queue (Deque)

Another type of queue called double ended queue also called Deque. Deque is a special type of data structure in which insertions and deletions will be done either at the front end or at the rear end of the queue. The operations can be performed on Deques are

Insert an item from front end
Insert an item from rear end
Delete an item from front end
Delete and item from rear end
Display the contents of queue

3. Circular queue

In an ordinary queue, as an item is inserted, the rear end identified by r is incremented by 1. Once r reaches QUEUE_SIZE-1, we say queue is full. Note that even if some elements are deleted from queue, because the rear end identified by r is still equal to QUEUE_SIZE-1 item cannot be inserted. But this disadvantage is overcome using circular queue. In circular queue an item can be published circularly. This can be achieved using the statement r = (r+1)%QUEUE_SIZE

The operations can be performed on circular queue are.

Insert an item from rear end
Delete an item from front end
Display queue contents

4. Priority queue

Such a queue where a job is processed based on the priority is called a priority queue