Playfair Cipher
1.not even the large number of keys in a monoalphabetic cipher provides security
2.one approach to improving security was to encrypt multiple letters
3.the Playfair Cipher is an example
4.invented by Charles Wheatstone in 1854,but named after his friend Baron Playfair
Playfair Key Matrix
1.a 5X5 matrix of letters based on a keyword
2.fill in letters of keyword (sans duplicates)
3.fill rest of matrix with other letters
Encrypting and Decrypting
-plaintext is encrypted two letters at a time
1. if a pair is a repeated letter, insert filler like X’
2. if both letters fall in the same row, replace each with letter to right (wrapping back to start from end)
3. if both letters fall in the same column, replace each with the letter below it (again wrapping to top from
bottom)
4. otherwise each letter is replaced by the letter in the same row and in the column of the other letter of the pair
THis is a web framework that use to do text parsing and extraction and update the text extract in a notepad file into the website. Using Django and mysql.
Spread-spectrum techniques are methods by which electromagnetic energy generated in a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth. These techniques are used for a variety of reasons, including the establishment of secure communications, increasing resistance to natural interference and jamming, and to prevent detec
C in A Nutshell
Learning a language--any language--involves a process wherein you learn to rely less and less on instruction and more increasingly on the aspects of the language you ve mastered. Whether you re learning French, Java, or C, at some point you ll set aside the tutorial and attempt to converse on your own. It s not necessary to know every subtle facet of French in order to speak it well, especially if there s a good dictionary available. Likewise, C programmers don t need to memorize every detail of C in order to write good programs. What they need instead is a reliable, comprehensive reference that they can keep nearby. C in a Nutshell is that reference.
In engineering, compensation is planning for side effects or other unintended issues in a design. The design of an invention can itself also be to compensate for some other existing issue or exception.
One example is in a voltage-controlled crystal oscillator (VCXO), which is normally affected not only by voltage, but to a lesser extent by temperature. A temperature-compensated version (a TCVCXO) is designed so that heat buildup within the enclosure of a transmitter or other such device will not alter the piezoelectric effect, thereby causing frequency drift.
Another example is motion compensation on digital cameras and video cameras, which keep a picture steady and not blurry.
MATLAB Adventures in Bifurcations & Chaos - (ABC++) is a GUI application, which runs in a MATLAB environment and has been designed for the For the exploration of bifurcations and chaos within the Chua Circuit paradigm
