'CSC524' Category

  • DNS and Eventual Consistency

    December 9, 2016

    Overview The internet Domain Name System (DNS) is an distributed, highly available database of facts, called Resource Records (RR) relevant to the operation of the Internet. Created by Paul Mockapetris in 1983, it is a harbinger for the highly available, distributed databases of today. The DNS system answers queries about the collection of RR’s by […]

  • The Public Key Infrastructure, and DigSigs

    April 22, 2015

    The SSL protocol provides all three of the basic security features: Confidentiality: the data is encrypted. Integrity: an authentication code is calculated to tie the statement to the holder of some secret information. Authenticity: said secret information can be known only by a certain counter-party. The confidentiality and integrity protocols we have studied assume a […]

  • SSH to the Lab Machines

    February 2, 2015

    Help with setting up your connection to the lab machines. If you are connecting to the department of computer science computer lab from ssh on your laptop, you should, if all possible, use public key authentication rather than a password authentication. Public key authentication is a technique that works through a key pair: a public […]

  • Hamming codes

    April 22, 2014

    The Huffman Code is a family of error correcting codes. To the information bits is added parity bits that depend fully and uniquely on the information bits. If there are bit errors in transmission, the balance between the information bits and parity bits, in fact, the balance between any of the bits, will be disturbed […]

  • Information and stuff

    April 16, 2014

    Last time we went over the Shannon-Hartley theorem. I’d like to summarize in simpler terms. Communication is the transport of information. Information is measured in bits, and is the measurement of the least number of yes-no questions whose answer will identify a message from among a fixed set of possible messages. For instance, if the […]

  • Addresses

    January 22, 2014

    For computers to communicate, the link and the network layer both have addresses, and they are not the same. The link layer (layer 2) has a MAC address, and the network layer (layer 3) has an IP address. This language is specific to the particular implementation technologies. If IP is not your layer 3, then […]

  • Shannon-Hartley Theorem

    April 24, 2012

    It was only around the turn of the century that information has existed as a scientific entity. Hartley wrote about it in 1928, as it became very important for the transmission of telegraph and telephone signals. By now, information is not just a natural quantity, it is a commercial quantity, bought and sold. We are […]

  • Zero knowledge login

    April 16, 2012

    Some authentication mechanisms depend on a secret knowledge to identify the subject. For instance, knowledge of a password. To prove knowledge of the password, the subject produces the password. This requires that the authenticating party know the password as well, so the knowledge is not that secret. The authenticating party must be authenticated, else that […]

  • TFTP Phase I

    March 28, 2007

    Due for Monday, April 2, Phase I of a TFTP Client/Server. Phaser I will implement: Recognition of command line options. Start up of server binding to port given in command line. Datagram construction of RRQ and WRQ by client, and sending UDP packet to server. Decode of RRQ and WRQ packet by server and dump […]

  • WiFi crash course

    February 23, 2007
 
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