Heres the code from file frequency_analysis.py

___________Code___________

#!/usr/bin/python

import sys,getopt,math

# Print Banner

def printBanner():

print 'Frequency analysis program v0.1a'

print ''

print ' o o'

print ' )-('

print ' (O O)'

print ' \\=/'

print ' .-"-.'

print ' //\\ /\\\\'

print ' _// / \\ \\_'

print ' =./ {,-.} \\.='

print ' || ||'

print ' || || hjw'

print ' __|| ||__ `97'

print ' `---" "---\' ASCII art by chris.com '

print ' +---------------------------------+'

print ' | Programmed by Youssif Al-Nashif |'

print ' | May 10, 2017 |'

print ' | CIS4367: Computer Security |'

print ' | Florida Polytechnic University |'

print ' +---------------------------------+ '

# Print usage

def usage():

print 'usage:'

print ' frequency_analysis.py -i '

print ''

sys.exit(2)

# Replace non-alphanumeric and non-space characters

def stripLine(text):

newText=''

newTextNoSpaces=''

for c in str.upper(text):

if (c>='A' and c

newText=newText+c

newTextNoSpaces=newTextNoSpaces+c

else:

newText=newText+' '

return newText,newTextNoSpaces

# Get text from file

def readFile(filename):

# read original file

text=''

textNoSpaces=''

file = open(filename)

line = file.readline()

while line != "":

line, lineNoSpaces=stripLine(line)

text=text+line

textNoSpaces=textNoSpaces+lineNoSpaces

line = file.readline()

return text, textNoSpaces

# Get text statistics

def getStatistics(textNoSpaces):

repetition=[]

totalNumberOfCharacters=0

for i in range(0,26):

repetition.append(0)

for c in textNoSpaces:

repetition[ord(c) - ord('A')] = repetition[ord(c) - ord('A')] + 1

totalNumberOfCharacters = totalNumberOfCharacters + 1

frequency = list(repetition)

for i in range(0, 26):

frequency[i] = float(repetition[i]) / totalNumberOfCharacters

return totalNumberOfCharacters, repetition, frequency

# Print statistics

def printStatistics(totalNumberOfCharacters,repetition,frequency):

print 'Total number of characters is: ', totalNumberOfCharacters, ' '

numberOfDigits = int(math.ceil(math.log(totalNumberOfCharacters, 10)))

rformat='{:'+str(numberOfDigits+5)+'d}'

rformat2='{:'+str(numberOfDigits+10)+'.'+str(numberOfDigits+1)+'f}'

for i in range (0,26):

# print chr(ord('A')+i),rformat.format(repetition[i]),rformat2.format(frequency[i])

print rformat2.format(frequency[i]),chr(ord('A')+i),rformat.format(repetition[i])

print

# Print statistics 2

def printStatistics2(totalNumberOfCharacters, repetition, frequency):

# print 'Total number of characters is: ', totalNumberOfCharacters, ' '

#numberOfDigits = int(math.ceil(math.log(totalNumberOfCharacters, 10)))

numberOfDigits=3

# rformat = '{:' + str(numberOfDigits + 5) + 'd}'

rformat = '{:' + str(numberOfDigits) + '.' + str(numberOfDigits) + 'f}'

for i in range(0, 26):

sys.stdout.write(rformat.format(frequency[i]))

sys.stdout.write(' & ')

if (i==12):

print

print

# Program Body

def main(argv):

# print banner

printBanner()

# get argument

if not argv:

usage()

try:

opts, args = getopt.getopt(argv,'i:',['inputFile='])

except getopt.GetoptError:

usage()

for opt, arg in opts:

if opt in ("-i", "--inputFile"):

inputFile = arg

text, textNoSpaces=readFile(inputFile)

totalNumberOfCharacters, repetition, frequency =getStatistics(textNoSpaces)

# printStatistics2(totalNumberOfCharacters, repetition, frequency)

printStatistics(totalNumberOfCharacters, repetition, frequency)

if __name__ == "__main__":

main(sys.argv[1:])

The Caeser cipher is a substitution cipher where each letter in the plaintext is replaced with a letter that is with distance n from the original letter in the alphabet. The distance n is the key for the cipher The encryption using the Caeser cipher for some letter a using a key n is expressed as: -E()-(+n) mod 26 To decrypt a Caeser cipher with a key n, for each letter y in the ciphertext find the following -Dy) ( n) mod 26 The Vigenre cipher is a modified version of the Caeser cipher by using the letters of a repeated keyword to encrypt the plain text. In this homework, you are asked to 1. modify your code from assignment 1 in order to be able to encrypt and decrypt using the Vigenre cipher 2. modify the posted python code frequency analysis.py to cryptanalysis a ciphertext gener- ated by the Vigenre cipher. Pick a long text novel, in the range 200k characters or more, from google and use it as your plaintext. Choose a 3 to 5 characters keyword, encrypt the plaintext, and perform the crypltanalysis on the ciphertext to determine the keylenght and the keyword