DES Python 코드
import random
pc_1= [49,42,35,28,21,14,7,0,
50,43,36,29,22,15,8,1,
51,44,37,30,23,16,9,2,
52,45,38,31,55,48,41,34,
27,20,13,6,54,47,40,33,
26,19,12,5,53,46,39,32,
25,18,11,4,24,17,10,3]
shift_n = [1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1]
pc_2=[13,16,10,23,0,4,2,27,
14,5,20,9,22,18,11,3,
25,7,15,6,26,19,12,1,
40,51,30,36,46,54,29,39,
50,44,32,47,43,48,38,55,
33,52,45,41,49,35,28,31]
p_box = [16,7,20,21,29,12,28,17,
1,15,23,26,5,18,31,10,
2,8,24,14,32,27,3,9,
19,13,30,6,22,11,4,25]
s_box = [[[14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7],
[0,15,7,4,14,2,13,10,3,6,12,11,9,5,3,8],
[4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0],
[15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13]],
[[15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10],
[3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5],
[0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15],
[13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9]],
[[10,0,9,14,6,3,15,5,1,14,12,7,11,4,2,8],
[13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1],
[13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7],
[1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12]],
[[7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15],
[13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9],
[10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4],
[3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14]],
[[2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9],
[14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6],
[4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14],
[11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3]],
[[12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11],
[10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8],
[9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6],
[4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13]],
[[4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1],
[13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6],
[1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2],
[6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12]],
[[13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7],
[1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2],
[7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8],
[2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11]]]
#text -> 8byte(64bit)
#ASKII --> 7bit -> "0"+ASCII --> 8bit
def StrToByte(text):
byte_array = bytearray(text.encode('ascii'))
str_list = []
for i in byte_array:
str_list.append("0"+str(format(i,"b")))
return ''.join(str_list)
def key_generator(n):
key = format(random.getrandbits(n),'b')
return key
key = key_generator(64).zfill(64)
def ByteToStr(text_byte):
list_byte = []
text_list = []
n=0
for i in text_byte:
list_byte.append(i)
n+=1
if(n==8):
bit_t = ''.join(list_byte)
str_b = "0b" + bit_t
text_list.append(chr(int(str_b,2)))
n=0
list_byte = []
return ''.join(text_list)
class Round_Func:
def __init__(self, R, key, pc1, pc2, shift_n, s_box, p_box, count):
self.__pc1 = pc_1
self.__pc2 = pc_2
self.__shift_n = shift_n
self.__sbox = s_box
self.__pbox = p_box
self.__r = R
self.__key = key
self.current_n = count
self.result = ""
# ExpansionR(R) = 32bit -> 48bit
def expansion_R(self) :
list_byte = []
e_byte = []
n = 0
m = 0
for i in self.__r:
list_byte.append(i)
n+=1
m+=1
if(n == 4):
byte_t = ''.join(list_byte)
if(m == 32):
head_text = self.__r[m-5]
tail_text = self.__r[0]
else:
head_text = self.__r[m-5]
tail_text = self.__r[m+1]
e_byte.append(head_text+byte_t+tail_text)
n = 0
list_byte = []
return ''.join(e_byte)
def shift_left(self, n, d, length):
result = ( (n<<d) & (2**length -1) ) | (n >>(length - d))
return result
def subkey_generator(self):
subkey_pc1 = [0] * len(self.__pc1)
subkey_pc2 = [0] * len(self.__pc2)
n = 0
for i in self.__pc1:
subkey_pc1[n] = self.__key[i]
n += 1
subkey_pc = ''.join(subkey_pc1)
c_subkey = subkey_pc[:int(len(subkey_pc1)/2)]
d_subkey = subkey_pc[int(len(subkey_pc1)/2):]
len_subkey = len(c_subkey)
c_shift = bin(self.shift_left(int(c_subkey,2), int(self.__shift_n[self.current_n]), len_subkey))[2:].zfill(len_subkey)
d_shift = bin(self.shift_left(int(d_subkey,2), int(self.__shift_n[self.current_n]), len_subkey))[2:].zfill(len_subkey)
subkey_shift = c_shift + d_shift
n = 0
for i in self.__pc2:
subkey_pc2[n] = subkey_shift[i]
n+=1
return ''.join(subkey_pc2)
def s_box(self, subkey_pc2):
n = 0
bit_list = []
s_box = []
for i in subkey_pc2 :
bit_list.append(i)
n += 1
if (n % 6) ==0 :
s_val = bin(self.__sbox[(n//6)-1][int(bit_list[0]+bit_list[5],2)]
[int(bit_list[1]+bit_list[2]+bit_list[3],2)])[2:].zfill(6)
s_box.append(s_val)
bit_list = []
return ''.join(s_box)
def p_box(self, s_box):
n = 0
subkey = [0]*len(self.__pbox)
for i in self.__pbox:
subkey[n] = s_box[i]
n += 1
return ''.join(subkey)
def active_func(self):
e_r = self.expansion_R()
s_g = self.subkey_generator()
subkey_xor = bin(int(e_r,2) ^ int(s_g,2))[2:].zfill(48)
subkey_sbox = self.s_box(subkey_xor)
self.result = self.p_box(subkey_sbox)
class DES:
def __init__ (self, plainText, key, num_round, pc_1, pc_2, shift_n, s_box, p_box):
# self.__plaintext = self.StrToByte(plainText)
self.__plaintext = plainText
self.__key = key
self.num_round = num_round
self.resulttext = ''
self.__pc1 = pc_1
self.__pc2 = pc_2
self.__shift_n = shift_n
self.__sbox = s_box
self.__pbox = p_box
def encryption(self):
l_text = self.__plaintext[:32]
r_text = self.__plaintext[32:]
for i in range(self.num_round):
r_tmp = r_text
f_obj = Round_Func(r_text, self.__key, self.__pc1, self.__pc2, self.__shift_n,
self.__sbox, self.__pbox, i)
f_obj.active_func()
result_round = bin(int(l_text,2) ^ int(f_obj.result,2))[2:].zfill(32)
r_text = result_round
l_text = r_tmp
self.resulttext = r_text + l_text
def decryption(self):
r_text = self.__plaintext[:32]
l_text = self.__plaintext[32:]
for i in range(self.num_round-1,-1,-1):
l_tmp = l_text
f_obj = Round_Func(l_text, self.__key, self.__pc1, self.__pc2, self.__shift_n,
self.__sbox, self.__pbox, i)
f_obj.active_func()
result_round = bin(int(r_text,2) ^ int(f_obj.result,2))[2:].zfill(32)
l_text = result_round
r_text = l_tmp
self.resulttext = l_text + r_text
Test Code
plaintext = "computer"
name = StrToByte(plaintext)
print("SongMinJ binary (ascii) ::",name)
obj = DES(name, key, 16, pc_1, pc_2, shift_n, s_box, p_box)
print("\n<<activate encryptio>>")
obj.encryption()
print("ciphertext ::",obj.resulttext)
print("ciphertext(str) ::",ByteToStr(obj.resulttext))
obj2 = DES(obj.resulttext, key, 16, pc_1, pc_2, shift_n, s_box, p_box)
print("\n\n<<activate decryption to ciphertext>>")
obj2.decryption()
print("decryption result ::", obj2.resulttext)
print("decryption result(str) ::", ByteToStr(obj2.resulttext))결과(출력값)
computer binary (ascii) :: 0110001101101111011011010111000001110101011101000110010101110010
<<activate encryptio>>
ciphertext :: 0111011001011100011000010111010001010000010101111111010101111000
ciphertext(str) :: v\atPWõx
<<activate decryption to ciphertext>>
decryption result :: 0110001101101111011011010111000001110101011101000110010101110010
decryption result(str) :: computer
개발세발스토오리