def e_substitution(plaintext, key):
# your code here
subString = key
subString = utilities.adjust_key(subString)
baseString = utilities.get_baseString()
baseString = utilities.adjust_key(baseString)
ciphertext = ''
for plainChar in plaintext:
#if(plainChar == 'Ã'):
#print(plainChar.isupper())
if (plainChar.isupper()):
upperFlag = True
else:
upperFlag = False
plainChar = plainChar.lower()
if plainChar in baseString:
indx = baseString.index(plainChar)
cipherChar = subString[indx]
cipherChar = cipherChar.upper() if upperFlag else cipherChar
else:
if (upperFlag == True):
cipherChar = plainChar.upper()
else:
cipherChar = plainChar
ciphertext += cipherChar
#print(ciphertext)
ciphertext = utilities.adjust_key(ciphertext)
return ciphertext
def test_q2(file1, file2):
print('Testing Encryption/decryption against sample file:')
plaintext = utilities.file_to_text('plaintext_subcipher_sample.txt')
ciphertext = utilities.file_to_text('ciphertext_subcipher_sample.txt')
key = utilities.adjust_key("""poejiqsrbltxwaznfcdhmvgkuy:'" !.?,-#;""")
ciphertext2 = solution.e_substitution(plaintext, key)
if ciphertext == ciphertext2:
print('\tEncryption Successful')
else:
print('\tEncryption failed')
plaintext2 = solution.d_substitution(ciphertext2, key)
if plaintext == plaintext2:
print('\tDecryption Successful')
else:
print('\tDecryption failed')
print()
# this is given you do not need to do anything for it
print('Cryptanalysis for Sample File:')
key = '''poejiqsrbltxwaznfcdhmvgkuy:'" !.?,-#;'''
print('found key = ', key)
print()
# Cryptanalysis of your file
plaintext = ''
ciphertext = ''
ciphertext2 = ''
plain1 = file1
cipher1 = file2
key = 0
ciphertext = utilities.file_to_text(cipher1)
print('Cryptanalysis of {}:'.format(cipher1))
key, plaintext = solution.cryptanalysis_substitution(ciphertext)
print('Key found: ', utilities.adjust_key(key))
print()
print('Plaintext:')
print(plaintext[:150])
print()
print('Verifying cryptanalysis results: ', end='')
ciphertext2 = solution.e_substitution(plaintext, key)
if ciphertext == ciphertext2:
print('OK')
else:
print('Something is not right!')
print()
solution.comments_q2()
return
def d_substitution(ciphertext, key):
plaintext = ""
alphabet = utilities.adjust_key(utilities.get_baseString())
#key = key
#alphabet = utilities.adjust_key(alphabet)
#print(alphabet)
#print(key)
for cipherChar in ciphertext:
if (cipherChar.isupper()):
upperFlag = True
else:
upperFlag = False
cipherChar = cipherChar.lower()
if cipherChar in alphabet:
indx = key.index(cipherChar)
plainChar = alphabet[indx]
plainChar = plainChar.upper() if upperFlag else plainChar
else:
if (upperFlag == True):
plainChar = cipherChar.upper()
else:
plainChar = cipherChar
plaintext += plainChar
#print(plaintext)
#plaintext = utilities.adjust_key(plaintext)
#print(utilities.adjust_key(plaintext))
return plaintext
def cryptanalysis_substitution(ciphertext):
key = '''yhribekafszmpxwojductnvlgq!-#;". '?,:''' #<--- change this line with your key
key = utilities.adjust_key(key) #<--- keep this line
plaintext =''
# add lines to decrypt the ciphertext
# remember to write your plaintext to file
return key,plaintext
def cryptanalysis_substitution(ciphertext):
key = '''smzokelxrcitbudnhwfpyaqvjg':"!-; ,#?.''' # <--- change this line with your key
key = utilities.adjust_key(key) # <--- keep this line
# add lines to decrypt the ciphertext
plaintext = d_substitution(ciphertext, key)
# remember to write your plaintext to file
utilities.text_to_file(plaintext, 'plaintext_Jiayao_Pang_q3.txt')
return key, plaintext
def cryptanalysis_substitution(ciphertext):
#key ='''rlpdeogkvbayiucntwqhfjxsmz //,"'?;///'''
key = '''rlpdeogkvbayiucntwqhfjxsmz ,.:"'?;!-#'''
key = utilities.adjust_key(key)
# add lines to decrypt the ciphertext
# key is not totally correct, fix this
plaintext = d_substitution(ciphertext, key)
return key, plaintext
def e_substitution(plaintext,key):
baseString = utilities.adjust_key(utilities.get_baseString())
subString = utilities.adjust_key(key)
ciphertext = ''
for plainChar in plaintext:
upperFlag = True if plainChar.isupper() else False
plainChar = plainChar.lower()
if plainChar in baseString:
indx = baseString.index(plainChar)
cipherChar = subString[indx]
cipherChar = cipherChar.upper() if upperFlag else cipherChar
else:
cipherChar = plainChar.upper() if upperFlag else plainChar
ciphertext += cipherChar
# if('#' in ciphertext):
ciphertext = utilities.adjust_key(ciphertext)
return ciphertext
def d_substitution(ciphertext,key):
# your code here
plaintext = ''
alphabet = utilities.adjust_key(utilities.get_baseString())
for cipherChar in ciphertext:
upperFlag = True if cipherChar.isupper() else False
cipherChar = cipherChar.lower()
if cipherChar in alphabet:
indx = key.index(cipherChar)
plainChar = alphabet[indx]
plainChar = plainChar.upper() if upperFlag else plainChar
else:
plainChar = cipherChar.upper() if upperFlag else cipherChar
plaintext+= plainChar
return plaintext
def d_substitution(ciphertext, key):
# your code here
plaintext = ''
ciphertext = ciphertext.replace('\n', '#')
key = utilities.adjust_key(key)
baseString = utilities.get_baseString()
for cipherChar in ciphertext:
upperFlag = True if cipherChar.isupper() else False
cipherChar = cipherChar.lower()
if cipherChar in key:
Index = key.index(cipherChar)
plainChar = baseString[Index]
plainChar = plainChar.upper() if upperFlag else plainChar
else:
plainChar = cipherChar.upper() if upperFlag else cipherChar
plaintext += plainChar
plaintext = plaintext.replace('#', '\n')
return plaintext
def e_substitution(plaintext, key):
# your code here
ciphertext = ''
plaintext = plaintext.replace('\n', '#')
key = utilities.adjust_key(key)
baseString = utilities.get_baseString()
for plainChar in plaintext:
upperFlag = True if plainChar.isupper() else False
plainChar = plainChar.lower()
if plainChar in baseString:
Index = baseString.index(plainChar)
cipherChar = key[Index]
cipherChar = cipherChar.upper() if upperFlag else cipherChar
else:
cipherChar = plainChar.upper() if upperFlag else plainChar
ciphertext += cipherChar
ciphertext = ciphertext.replace('#', '\n')
return ciphertext