Computer Networking and Management Essay Example | Topics and Well Written Essays - 2000 words

Computer Networking and Management - Essay Example y or through a communication channel), and there may be a probability that an unauthorized person can access the secret keys during their transmission. (‘Harvard style’, n.d.a) Secret-key systems require the sharing of some secret or sometimes trust of a third party to support authentication. As a result, a sender can repudiate a previously authenticated message by claiming that the shared secret was somehow compromised by one of the parties sharing the secret. For example, the Kerberos secret-key authentication system keeps copies of the secret keys of all uses in a central database; an attack on the database would allow widespread forgery. On the other hand, since each user has sole responsibility for protecting his or her private key, public-key authentication effectively prevents any sort of repudiation; this property of public-key authentication is often called non-repudiation. (‘Harvard style’, n.d.a) Unlike secret-key cryptography, public-key cryptography may be vulnerable to impersonation even if user’s private keys are not available. A successful attack on certification authority will allow an adversary to impersonate whomever the adversary chooses by using a public-key certificate from the compromised authority to bind a key of the adversary’s choice to the name of another user. (‘Harvard style’, n.d.a) RSA, which stands for Rivest, Shamir and Adleman, was the first and most widely used public key cryptosystem. Developed in 1977 by three M.I.T. professors, it is based on the mathematical properties of modulo arithmetic. (‘Harvard style’, n.d.c) Modulo arithmetic is much like normal arithmetic, but only uses integers no longer than a limiting number, the modulus (usually written as m). Any result larger than the modulus has the modulus subtracted from it repeatedly until it is less than the modulus. Thus, instead of the numbers forming a line, modulo numbers can be thought of as forming a ring, when the largest number loops back to