def e_SDES_CBC(plaintext, key):
undefined = utilities.get_undefined(plaintext, utilities.get_B6Code())
text = utilities.remove_undefined(plaintext, utilities.get_B6Code())
size = int(int(get_SDES_value('block_size')) / 6)
blocks = utilities.text_to_blocks(text, size)
while len(blocks[-1]) != size:
blocks[-1] += 'Q'
IV = get_IV()
ciphertext = ''
for block in blocks:
cipher_block = ''
for b in block:
cipher_block += encode_B6(b)
cipher_block = utilities.xor(cipher_block, IV)
for i in range(int(get_SDES_value('rounds'))):
cipher_block = feistel(cipher_block, get_subKey(key, i + 1))
cipher_block = cipher_block[
int(len(cipher_block) /
2):] + cipher_block[:int(len(cipher_block) / 2)]
b_blocks = utilities.text_to_blocks(cipher_block, 6)
for b_b in b_blocks:
ciphertext += decode_B6(b_b)
IV = cipher_block
ciphertext = utilities.insert_undefinedList(ciphertext, undefined)
return ciphertext
def d_SDES_ECB(ciphertext, key):
# your code here
if not isinstance(ciphertext, str) or len(ciphertext) == 0:
print('Error(d_SDES_ECB): Invalid input', end='')
return ''
if get_SDES_value('encoding_type') == '' or get_SDES_value(
'block_size') == '' or get_SDES_value('key_size') == '':
print('Error(d_SDES_ECB): Invalid configuration', end='')
return ''
if len(key) == 0:
if get_SDES_value('p') == '' or get_SDES_value(
'q') == '' or get_SDES_value('key_size') == '':
print('Error(d_SDES_ECB): Invalid key', end='')
return ''
key = generate_key_SDES()
if not utilities.is_binary(key):
print('Error(d_SDES_ECB): Invalid key', end='')
return ''
if len(key) != int(get_SDES_value('key_size')):
print('Error(d_SDES_ECB): Invalid key', end='')
return ''
undefined = utilities.get_undefined(ciphertext, utilities.get_B6Code())
text = utilities.remove_undefined(ciphertext, utilities.get_B6Code())
size = int(int(get_SDES_value('block_size')) / 6)
blocks = utilities.text_to_blocks(text, size)
plaintext = ''
for block in blocks:
plain_block = ''
for b in block:
plain_block += encode_B6(b)
rounds = int(get_SDES_value('rounds'))
for i in range(rounds):
plain_block = feistel(plain_block, get_subKey(key, rounds - i))
plain_block = plain_block[int(
len(plain_block) / 2):] + plain_block[:int(len(plain_block) / 2)]
b_blocks = utilities.text_to_blocks(plain_block, 6)
for b_b in b_blocks:
plaintext += decode_B6(b_b)
while plaintext[-1] == 'Q':
plaintext = plaintext[:-1]
plaintext = utilities.insert_undefinedList(plaintext, undefined)
return plaintext
def e_SDES_ECB(plaintext, key):
# your code here
if not isinstance(plaintext, str) or len(plaintext) == 0:
print('Error(e_SDES_ECB): Invalid input', end='')
return ''
if get_SDES_value('encoding_type') == '' or get_SDES_value(
'block_size') == '' or get_SDES_value('key_size') == '':
print('Error(e_SDES_ECB): Invalid configuration', end='')
return ''
if len(key) == 0:
if get_SDES_value('p') == '' or get_SDES_value(
'q') == '' or get_SDES_value('key_size') == '':
print('Error(e_SDES_ECB): Invalid key', end='')
return ''
key = generate_key_SDES()
if not utilities.is_binary(key):
print('Error(e_SDES_ECB): Invalid key', end='')
return ''
if len(key) != int(get_SDES_value('key_size')):
print('Error(e_SDES_ECB): Invalid key', end='')
return ''
undefined = utilities.get_undefined(plaintext, utilities.get_B6Code())
text = utilities.remove_undefined(plaintext, utilities.get_B6Code())
size = int(int(get_SDES_value('block_size')) / 6)
blocks = utilities.text_to_blocks(text, size)
while len(blocks[-1]) != size:
blocks[-1] += 'Q'
ciphertext = ''
for block in blocks:
cipher_block = ''
for b in block:
cipher_block += encode_B6(b)
for i in range(int(get_SDES_value('rounds'))):
cipher_block = feistel(cipher_block, get_subKey(key, i + 1))
cipher_block = cipher_block[
int(len(cipher_block) /
2):] + cipher_block[:int(len(cipher_block) / 2)]
b_blocks = utilities.text_to_blocks(cipher_block, 6)
for b_b in b_blocks:
ciphertext += decode_B6(b_b)
ciphertext = utilities.insert_undefinedList(ciphertext, undefined)
return ciphertext
def decode_B6(b):
b6 = utilities.get_B6Code()
if not isinstance(b, str) or len(b)!=6:
print('Error(decode_B6): Invalid input')
return ''
else:
c = b6[utilities.bin_to_dec(b)]
return c
def encode_B6(c):
b6 = utilities.get_B6Code()
if not isinstance(c, str) or len(c)!=1:
print('Error(encode_B6): invalid input')
return ''
else:
b = utilities.dec_to_bin(b6.index(c),6)
return b
def decode(b,codeType):
if not utilities.is_binary(b):
print('Error(decode): invalid input',end ='')
return ''
if codeType == 'ASCII':
c = chr(utilities.bin_to_dec(b))
elif codeType == 'B6':
b6 = utilities.get_B6Code()
c = b6[utilities.bin_to_dec(b)]
else:
print('Error(decode): Unsupported Coding Type',end ='')
return ''
return c
def decode_B6(b):
# your code here
if not utilities.is_binary(b):
print('Error(decode_B6): invalid input', end='')
return ''
if len(b) != 6:
print('Error(decode_B6): invalid input', end='')
return ''
b6_code = utilities.get_B6Code()
c = b6_code[utilities.bin_to_dec(b)]
return c
def d_SDES_OFB(ciphertext, key):
undefined = utilities.get_undefined(ciphertext, utilities.get_B6Code())
text = utilities.remove_undefined(ciphertext, utilities.get_B6Code())
size = int(int(get_SDES_value('block_size')) / 6)
blocks = utilities.text_to_blocks(text, size)
IV = get_IV()
plaintext = ''
counter = 0
for block in blocks:
temp = ''
plain_block = IV
rounds = int(get_SDES_value('rounds'))
for i in range(rounds):
plain_block = feistel(plain_block, get_subKey(key, i + 1))
plain_block = plain_block[int(
len(plain_block) / 2):] + plain_block[:int(len(plain_block) / 2)]
IV = plain_block
for b in block:
temp += encode_B6(b)
if counter <= len(blocks) - 2:
plain_block = utilities.xor(plain_block, temp)
else:
plain_block = utilities.xor(temp, plain_block[:len(temp)])
b_blocks = utilities.text_to_blocks(plain_block, 6)
for b_b in b_blocks:
plaintext += decode_B6(b_b)
counter += 1
plaintext = utilities.insert_undefinedList(plaintext, undefined)
return plaintext
def d_SDES_CBC(ciphertext, key):
undefined = utilities.get_undefined(ciphertext, utilities.get_B6Code())
text = utilities.remove_undefined(ciphertext, utilities.get_B6Code())
size = int(int(get_SDES_value('block_size')) / 6)
blocks = utilities.text_to_blocks(text, size)
plaintext = ''
IV = get_IV()
temp = ''
for block in blocks:
plain_block = ''
for b in block:
plain_block += encode_B6(b)
temp = plain_block
rounds = int(get_SDES_value('rounds'))
for i in range(rounds):
plain_block = feistel(plain_block, get_subKey(key, rounds - i))
plain_block = plain_block[int(
len(plain_block) / 2):] + plain_block[:int(len(plain_block) / 2)]
plain_block = utilities.xor(IV, plain_block)
b_blocks = utilities.text_to_blocks(plain_block, 6)
for b_b in b_blocks:
plaintext += decode_B6(b_b)
IV = temp
while plaintext[-1] == 'Q':
plaintext = plaintext[:-1]
plaintext = utilities.insert_undefinedList(plaintext, undefined)
return plaintext
def encode_B6(c):
# your code here
if not isinstance(c, str):
print('Error(encode_B6): invalid input', end='')
return ''
if len(c) != 1:
print('Error(encode_B6): invalid input', end='')
return ''
b6_code = utilities.get_B6Code()
if c not in b6_code:
return ''
i = b6_code.index(c)
b = utilities.dec_to_bin(i, 6)
return b
def d_SDES(ciphertext,key):
plaintexttext = ''
if isinstance(ciphertext, str) and ciphertext != '':
conf = get_SDES_config()
k = get_SDES_value('key_size')
r = get_SDES_value('rounds')
e = get_SDES_value('encoding_type')
b = get_SDES_value('block_size')
p = get_SDES_value('p')
q = get_SDES_value('q')
if k!= '' and r != '' and e != '' and b !='':
if key == '' and p!= '' and q !='':
key = generate_key_SDES()
if key!='' and int(k) == len(key):
k = int(k)
r = int(r)
b = int(b)
b6_base = utilities.get_B6Code()
sv_undef = utilities.get_undefined(ciphertext, b6_base)
text = utilities.remove_undefined(ciphertext, b6_base)
blk_text = []
while len(text)%2 != 0:
text+='Q'
for i in range(0,len(text),2):
blk_text.append(text[i]+text[i+1])
round = 0
enc_text = []
for x in blk_text:
enc_text.append(encode(x[0],e)+encode(x[1],e))
stream = ''
for blocks in enc_text:
for rounds in range(r):
if rounds == 0:
rnd_text = blocks
ki = get_subKey(key,r-rounds)
rnd_text = feistel(rnd_text, ki)
if rounds == r-1:
m = int(len(rnd_text)//2)
Li = rnd_text[:m]
Ri = rnd_text[m:]
rnd_text = Ri+Li
stream += rnd_text
plaintext = ''
for s in range(0, len(stream), b//2):
plaintext+=decode(stream[s:s+b//2], e)
plaintext = utilities.insert_undefinedList(plaintext, sv_undef)
plaintext = plaintext.strip('Q')
elif key!= '' and int(k) != len(key):
print('Error(d_SDES): Invalid key')
return ''
elif key=='' and p == '' or q == '':
print('Error(d_SDES): Invalid key')
return ''
else:
print("Error(d_SDES): Invalid configuration")
return ''
else:
print("Error(d_SDES): Invalid input")
return ''
return plaintext