The Complete Codes

Digital signatures A digital signature or digital signature scheme is a mathematical scheme for demonstrating the authenticity of a digital message or document. A valid digital signature gives a recipient reason to believe that the message was created by a known sender such that they cannot deny sending it (authentication and non-repudiation) and that the message was not altered in transit (integrity). Digital signatures are commonly used for software distribution, financial transactions, and in other cases where it is important to detect forgery or tampering. A digital signature (NOT a digital certificate) is an electronic signature that can be used to authenticate the identity of the sender of a message or the signer of a document, and possibly to ensure that the original content of the message or document that has been sent is unchanged. Digital signatures are easily transportable, cannot be imitated by someone else, and can be automatically time-stamped. The ability to ensur

NETWORK SECURITY Network security consists of the provisions and policies adopted by a network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources. Network security involves the authorization of access to data in a network, which is controlled by the network administrator. Users choose or are assigned an ID and password or other authenticating information that allows them access to information and programs within their authority. Network security concerns: Secrecy Secrecy has to do with keeping information out of the hands of unauthorized users. This is what usually comes to mind when people think about network security. Authentication Authentication deals with determining whom you are talking to before revealing sensitive information or entering into a business deal. Non-repudiation and Integrity Control Non-repudiation deals related with signatures. Assurance that a m

Topology means the physical design of a network including the devices, location and cable installation. Logical Topology refers to the fact that how data actually transfers in a network as opposed to its design.

Computer Network | Ethernet (802.3) Ethernet is the most widely-installed local area network (LAN) technology. Ethernet was originally developed by Xerox from an earlier specification called Aloha net and then developed further by Xerox, DEC, and Intel. An Ethernet LAN typically uses coaxial cable or special grades of twisted pair wires. Ethernet is also used in wireless. Ethernet is standardized as IEEE 802.3 that specifies a CSMA/CD bus network. CSMA/CD (Carrier Sense Multiple Access / Collision Detect) is used to detect the collision in the network. An Ethernet CSMA/CD can be implemented using a Bus or even a Star topology.

Computer Network According to Tanenbaum , computer network is a collection of ―autonomous‖ computers interconnected by a single technology. It is a collection of computers and other devices interconnected by communication channels that allow sharing of resources and information. The connection can be done as peer-to-peer or client/server.