文件列表:

Utilities (0, 2017-02-05)
Utilities\ScanLine.cpp (5147, 2017-02-05)
Utilities\ScanLine.h (1421, 2017-02-05)
Utilities\Scanner.cpp (6539, 2017-02-05)
Utilities\Scanner.h (1058, 2017-02-05)
Utilities\Utils.cpp (23648, 2017-02-05)
Utilities\Utils.h (3675, 2017-02-05)
ciphertext.txt (330, 2017-02-05)
decrypt.cpp (2660, 2017-02-05)
decrypt.h (463, 2017-02-05)
findKeyLength.cpp (3640, 2017-02-05)
findKeyLength.h (433, 2017-02-05)
findKeyLetter.cpp (7637, 2017-02-05)
findKeyLetter.h (622, 2017-02-05)
letterlookup.cpp (1617, 2017-02-05)
main.cpp (2036, 2017-02-05)
main.h (405, 2017-02-05)
makefile (1014, 2017-02-05)
printVector.cpp (1369, 2017-02-05)
printVector.h (420, 2017-02-05)
testcipher.txt (337, 2017-02-05)
translateLetters.cpp (4140, 2017-02-05)
translateLetters.h (308, 2017-02-05)

README ***** Compilation ***** 1. In a terminal window, navigate to the project directory. Type the 'make' command, and the program will compile, resulting in an executable called 'vigenere'. ***** Execution ***** 2. To execute the program, enter the command './vigenere ' where is the text file containing the ciphertext you want decrypted. Pressing enter will run this command, the output of which will be printed in the terminal window. (A copy of the assignment's ciphertext is included in this directory, and is called 'ciphertext.txt'.) ***** Interpreting Output ***** 3. There is quite a lot of output so that you can get a sense of how the program operates: - First, the program will print out the logs of opening and closing the input stream from the text file. Next, the number of total characters and the full text is printed. - Second, the process for finding the keylength is printed. This consists of the number of coincidences found for each comparison of two copies of the ciphertext, with one set being shifted by one element before each comparison. A more in-depth explanation of this process is given in the actual code itself. The keylength is then determined to be equal to the size of the offset that resulted in the maximum number of coincidences. This number is printed next. - The next section of text consists of a certain number of 'passes,' which will equal the recently-determined key length. So, for each letter of the key, the program will calculate the dot product between a vector containing every i-th letter of the cipher text, where i is the keylength, and a vector containing the standard Engligh letter frequencies. So, for a keylength = 5, letters 0, 4, 9... will be in the first vector. Letters 1, 5, 10... will be in the second pass, and so on. For each pass, the program prints the letters it is considering, the size of the vector holding them, and then the frequency of each letter, in alphabetical order. It then outputs the maximum dot product calculated and which shift of the ciphertext vector resulted in that maximum amount. This shift is saved. After all passes are complete, the saved shift numbers are translated into letters, which are printed to the screen. This is the key. - The final section shows the now-decoded plaintext. ***** Notes ***** This README is not meant to fully explain the code, but rather to explain what is being output to the screen when the program is run. There are further explanations of how the program works in the code itself. The Utilities directory included here contains program files written by Duncan Buell for use in his CSCE 240 class. Specifically, the Scanner.cpp file was used in this program to read in the text file.

近期下载者：

相关文件：

评论：[我要评论] [举报此文件]

收藏者：