def cryptanalysis_block_rotate(ciphertext, arguments=[0, 0, 0]):
dict_list = utilities.load_dictionary(DICT_FILE)
if (arguments[0] > 0
and arguments[1] > 0) and (arguments[0]
== arguments[1]) and arguments[2] == 0:
for i in range(arguments[1]):
text = d_block_rotate(ciphertext, (arguments[1], i))
if utilities.is_plaintext(text, dict_list) == True:
return (arguments[1], i), text
if (arguments[0] == 0 and arguments[1] == 0) and (arguments[2] > 0):
for i in range(arguments[0], arguments[1]):
text = d_block_rotate(ciphertext, (i, arguments[2]))
if utilities.is_plaintext(text, dict_list) == True:
return (i, arguments[2]), text
if (arguments[0] > 0 or arguments[1] > 0) and arguments[2] == 0:
if arguments[1] == 0:
arguments[1] = BLOCK_MAX_SIZE
if arguments[0] == 0:
arguments[0] = 1
for i in range(arguments[0], arguments[1]):
for j in range(arguments[1]):
text = d_block_rotate(ciphertext, (i, j))
if utilities.is_plaintext(text, dict_list) == True:
return (i, j), text
if (arguments[0] == 0 and arguments[1] == 0 and arguments[2] == 0):
if arguments[1] == 0:
arguments[1] = BLOCK_MAX_SIZE
if arguments[0] == 0:
arguments[0] = 1
for i in range(arguments[0], arguments[1]):
for j in range(arguments[1]):
text = d_block_rotate(ciphertext, (i, j))
if utilities.is_plaintext(text, dict_list) == True:
return (i, j), text
return '', ''
def cryptanalysis_xshift(ciphertext):
#your code here
alphabet = "abcdefghijklmnopqrstuvwxyz"
atbash = alphabet[::-1]
listOfData = []
combinations = [(alphabet + alphabet.upper()), (atbash + atbash.upper()),
(alphabet + atbash.upper()), (atbash + alphabet.upper())]
for combo in combinations:
i = 0
while (i < 26):
plain_test = d_xshift(ciphertext, tuple((combo, i)))
chi_value = utilities.get_chiSquared(plain_test)
listOfData.append(tuple((plain_test, chi_value, i, combo)))
i += 1
listOfData = sorted(listOfData, key=lambda tup: tup[1])
for value in listOfData:
if (utilities.is_plaintext(value[0], 'engmix.txt', 0.9)):
key = tuple((value[3], value[2]))
plaintext = value[0]
#print(plaintext)
return key, plaintext
return key, plaintext
def cryptanalysis_xshift(ciphertext):
#your code here
key = 0
plaintext = ''
regLower = 'abcdefghijklmnopqrstuvwxyz'
regUpper = regLower.upper()
atbashLower = regLower[::-1]
atbashUpper = atbashLower.upper()
possibilities = [regLower+regUpper, regLower+atbashUpper, atbashLower+regUpper, atbashLower+atbashUpper]
listTuples = []
for possible in possibilities:
for i in range(26):
decr = d_xshift(ciphertext, tuple((str(possible), i)))
chi = utilities.get_chiSquared(decr)
listTuples.append(tuple((decr, chi, i, possible)))
listTuple = sorted(listTuples, key=lambda tup: tup[1])
for item in listTuple:
if(utilities.is_plaintext(item[0], 'engmix.txt', 0.8)):
key = tuple((item[3], item[2]))
plaintext = item[0]
return key, plaintext
return key, plaintext
def cryptanalysis_xshift(ciphertext):
# your code here
wordList = utilities.text_to_words(ciphertext)
single = list()
for word in wordList:
if len(word) == 1 and word not in single:
single.append(word)
shiftStringList = utilities.get_shiftStringList()
for s in single:
for shiftString in shiftStringList:
now_c = shiftString.index(s)
ori_c = shiftString.index('I')
dis = now_c - ori_c if now_c > ori_c else now_c - ori_c + 52
plaintext = d_xshift(ciphertext, (shiftString, dis))
if utilities.is_plaintext(plaintext, 'engmix.txt', 0.90):
utilities.text_to_file(plaintext, 'plaintext_Jiayao_Pang_q2.txt')
return (shiftString, dis), plaintext
key = ('', 0)
plaintext = ''
return key, plaintext
def cryptanalysis_xcrypt(ciphertext):
# your code here
plaintext = ''
i = 0
for i in range(1,501):
plain = d_xcrypt(ciphertext, i)
is_plain = utilities.is_plaintext(plain, "engmix.txt", 0.8)
if(is_plain == True):
return i, plain
return i, plaintext
def cryptanalysis_vigenere(ciphertext):
# yoru code here
FriedmanL = utilities.getKeyL_friedman(ciphertext)
ShiftL = utilities.getKeyL_shift(ciphertext)
non_alpha = utilities.get_nonalpha(ciphertext)
if ShiftL != 1:
# try every possible size
start = min(FriedmanL, ShiftL)
if start >= 3:
start -= 1
end = max(FriedmanL, ShiftL) + 2
modified = utilities.remove_nonalpha(ciphertext)
for size in range(start, end):
plaintext = ''
shiftList = []
blocks = utilities.text_to_blocks(modified, size)
baskets = utilities.blocks_to_baskets(blocks)
for element in baskets:
# get the list of chi_squared for every shift
chiList = [round(utilities.get_chiSquared(utilities.d_shift(element, (i, 'l'))), 4)
for i in range(26)]
shiftList.append(chiList.index(min(chiList)))
for i in range(len(baskets)):
baskets[i] = utilities.d_shift(baskets[i], (shiftList[i], 'l'))
result = utilities.blocks_to_baskets(baskets)
for e in result:
plaintext += e
plaintext = utilities.insert_nonalpha(plaintext, non_alpha)
if utilities.is_plaintext(plaintext, 'engmix.txt', 0.90):
plain = utilities.remove_nonalpha(plaintext)[:size]
key = ''
v_square = utilities.get_vigenereSquare()
counter = 0
for pChar in plain:
pIndex = v_square[0].index(pChar)
kIndex = v_square[pIndex].index(blocks[0][counter])
counter += 1
key += v_square[0][kIndex]
utilities.text_to_file(plaintext, 'plaintext_Jiayao_Pang_q4.txt')
return key, plaintext
key = 0
plaintext = ''
return key, plaintext
def _restore_word_playfair(word, dict_list):
new_word = word
x_count = 0
i = 0
x_char = 'x'
if new_word.isupper() == True:
x_char = 'X'
if utilities.is_plaintext(new_word, dict_list, 1) == True:
return new_word
else:
while i < len(new_word):
if new_word[i] == x_char and i != 0 and x_count < 2:
# print('test1')
new_word = new_word[:i] + new_word[i - 1] + new_word[i + 1:]
if utilities.is_plaintext(word, dict_list, 1) == True:
return new_word
x_count += 1
i += 1
if utilities.is_plaintext(new_word, dict_list, 1) == False:
j = 0
x_count = 0
x_skip = 1
new_word = word
while j < len(new_word):
if new_word[j] == x_char and j != 0 and x_count < 2:
# print('test2')
if x_skip == 0:
x_skip -= 1
new_word = new_word[:j] + new_word[j - 1] + new_word[j +
1:]
if utilities.is_plaintext(word, dict_list, 1) == True:
return new_word
else:
x_skip -= 1
x_count += 1
j += 1
if utilities.is_plaintext(new_word, dict_list, 1) == False:
k = 0
x_count = 0
x_skip = 1
new_word = word
while k < len(new_word):
if new_word[k] == x_char and k != 0 and x_count < 2:
# print('test3')
if x_skip == 1:
x_skip -= 1
new_word = new_word[:k] + new_word[k - 1] + new_word[k +
1:]
if utilities.is_plaintext(word, dict_list, 1) == True:
return new_word
else:
x_skip -= 1
x_count += 1
k += 1
return new_word
def cryptanalysis_xcrypt(ciphertext):
for i in range(1, 501):
#print("i = " + str(i))
plaintext = d_xcrypt(ciphertext, i)
#I = utilities.get_indexOfCoin(ciphertext)
#print(plaintext)
is_plain = utilities.is_plaintext(plaintext, "engmix.txt", 0.8)
#print(is_plain)
if (is_plain == True):
print(plaintext)
return i, plaintext
# your code here
#print(plaintext)
return i, plaintext
def cryptanalysis1_myszkowski(ciphertext):
# your code here
possible = ['aab', 'aba', 'baa', 'bba', 'bab', 'abb']
dictList = utilities.load_dictionary('engmix.txt')
attempts = 0
for pos in possible:
plaintext = d_myszkowski(ciphertext, pos)
attempts += 1
if utilities.is_plaintext(plaintext, dictList, 0.90):
print('key found after ' + str(attempts) + ' attempts')
return plaintext, pos
return '', ''
def cryptanalysis_xcrypt(ciphertext):
# your code here
if ciphertext[-1] == 'q':
lastIndex = ciphertext.rfind('q')
Index = ciphertext.rfind('q', 0, lastIndex)
possibleKey = len(ciphertext) / (lastIndex - Index)
plaintext = d_xcrypt(ciphertext, possibleKey)
if utilities.is_plaintext(plaintext, 'engmix.txt', 0.90):
utilities.text_to_file(plaintext, 'plaintext_Jiayao_Pang_q1.txt')
return int(possibleKey), plaintext
found = False
for i in range(1, 501):
plaintext = d_xcrypt(ciphertext, i)
if utilities.is_plaintext(plaintext, 'engmix.txt', 0.90):
found = True
break
if found is False:
return 0, ''
utilities.text_to_file(plaintext, 'plaintext_Jiayao_Pang_q1.txt')
return i, plaintext
def verify_RSA(message):
# your code here
file = open('public_keys.txt', 'r')
content = file.read()
info = content.split('\n')
public_keys = []
for i in info:
temp = i.split(' ')
public_keys.append(temp)
dictList = utilities.load_dictionary('engmix.txt')
for key in public_keys:
plaintext = d_RSA(message, (int(key[1]), int(key[2])))
if utilities.is_plaintext(plaintext, dictList, 0.90):
return key[0], plaintext
return 'Unknown', ''
def cryptanalysis3_myszkowski(ciphertext):
# your code here
init_list = [[0, 0, 0, 1, 2], [1, 1, 1, 0, 2], [2, 2, 2, 0, 1]]
lower = utilities.get_lower()
dictList = utilities.load_dictionary('engmix.txt')
attempts = 0
for init in init_list:
combinations = SDES.combinations(init)
for com in combinations:
key = ''
for num in com:
key += lower[num]
plaintext = d_myszkowski(ciphertext, key)
attempts += 1
if utilities.is_plaintext(plaintext, dictList, 0.80):
print('key found after ' + str(attempts) + ' attempts')
return plaintext, key
return '', ''
def cryptanalysis2_myszkowski(ciphertext, length):
# your code here
dictList = utilities.load_dictionary('engmix.txt')
attempts = 0
for l in dictList:
for word in l:
if len(word) == length:
remove_repetition = ''
for c in word.lower():
if c not in remove_repetition:
remove_repetition += c
if len(remove_repetition) != length and len(
remove_repetition) != 1:
plaintext = d_myszkowski(ciphertext, word)
attempts += 1
if utilities.is_plaintext(plaintext, dictList, 0.90):
print('key found after ' + str(attempts) + ' attempts')
return plaintext, word
return '', ''
def cryptanalysis_mathCipher(ciphertext):
# your code here
baseString = utilities.get_baseString()
length = len(baseString)
dictList = utilities.load_dictionary('engmix.txt')
sub_baseString = []
for j in range(25, length):
sub_baseString.append(baseString[:j + 1])
attempts = 0
for n_s in sub_baseString:
m = len(n_s)
m_i_table = mod.mul_inv_table(m)
for mi1 in m_i_table[0]:
if m_i_table[1][mi1] != 'NA':
for mi2 in m_i_table[0]:
if m_i_table[1][mi2] != 'NA':
for c in range(m):
if mod.residue(mi2**2 - c, m) != 0:
k = [mi1, mi2, c]
key = (n_s, k)
plaintext = d_mathCipher(ciphertext, key)
attempts += 1
if len(utilities.remove_nonalpha(
plaintext)) < len(plaintext) / 2:
continue
if utilities.is_plaintext(
plaintext, dictList, 0.90):
print('key found after ' + str(attempts) +
' attempts')
return plaintext, key
return '', ''
def d_type3(ciphertext):
alpha = utilities.get_lower()
dictList = utilities.load_dictionary('engmix.txt')
for a in range(0, 5):
for b in range(0, 5):
for c in range(0, 5):
for d in range(0, 5):
key_matrix = matrix.new_matrix(2, 2, 0)
key_matrix[0][0] = a
key_matrix[0][1] = b
key_matrix[1][0] = c
key_matrix[1][1] = d
if mod.has_mul_inv(a * d - b * c, 26):
key = ''
for i in range(2):
for j in range(2):
key += alpha[key_matrix[i][j]]
first = d_hill(ciphertext, key)
k, plain = cryptanalysis_shift(first)
if utilities.is_plaintext(plain, dictList, 0.70):
return plain, (k, key)