from libnum import *
import base64
def stob(string):
res = ''
for i in string:
f = bin(ord(i))[2:]
f = '0'*(8-len(f)) + f
res += f
return res
def rol(s,n):
return s[n:]+s[:n]
def xor(s1,s2):
res = ''
for i in range(len(s1)):
res += str(int(s1[i],10)^int(s2[i],10))
return res
def ip(string):
res = ''
ip_list = [58,50,42,34,26,18,10,2,60,52,44,36,28,20,12,4,62,54,46,38,30,22,14,6,64,56,48,40,32,24,16,8,57,49,41,33,25,17,9,1,59,51,43,35,27,19,11,3,61,53,45,37,29,21,13,5,63,55,47,39,31,23,15,7]
for i in ip_list:
res += string[i-1]
return res
def ip_1(string):
res = ''
ip_list = [40,8,48,16,56,24,64,32,39,7,47,15,55,23,63,31,38,6,46,14,54,22,62,30,37,5,45,13,53,21,61,29,36,4,44,12,52,20,60,28,35,3,43,11,51,19,59,27,34,2,42,10,50,18,58,26,33,1,41,9,49,17,57,25]
for i in ip_list:
res += string[i-1]
return res
def box_s(string):
res = ''
s_list = [[14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7,0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8,4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0,15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13],[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],[10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8,13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1,13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7,1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12],[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]]
for i in range(len(string)/6):
a = int((string[i*6]+string[i*6+5]),2)
b = int(string[i*6+1:i*6+5],2)
res += (bin(s_list[i][a*16+b])[2:]).zfill(4)
return res
def pc_1(string):
res = ''
pc_1_list = [57,49,41,33,25,17,9,1,58,50,42,34,26,18,10,2,59,51,43,35,27,19,11,3,60,52,44,36,63,55,47,39,31,23,15,7,62,54,46,38,30,22,14,6,61,53,45,37,29,21,13,5,28,20,12,4]
for i in pc_1_list:
res += string[i-1]
return res
def pc_2(string):
res = ''
pc_2_list = [14,17,11,24,1,5,3,28,15,6,21,10,23,19,12,4,26,8,16,7,27,20,13,2,41,52,31,37,47,55,30,40,51,45,33,48,44,49,39,56,34,53,46,42,50,36,29,32]
for i in pc_2_list:
res += string[i-1]
return res
def box_e(string):
res = ''
e_list = [32,1,2,3,4,5,4,5,6,7,8,9,8,9,10,11,12,13,12,13,14,15,16,17,16,17,18,19,20,21,20,21,22,23,24,25,24,25,26,27,28,29,28,29,30,31,32,1]
for i in e_list:
res += string[i-1]
return res
def box_p(string):
res = ''
p_list = [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]
for i in p_list:
res += string[i-1]
return res
def fun_f(string,key):
str_e = box_e(string)
str_xor = xor(str_e,key)
str_s = box_s(str_xor)
str_p = box_p(str_s)
return str_p
def box_key(string):
num = [1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1]
key_list = []
key_1 = pc_1(string)
key_c = key_1[0:28]
key_d = key_1[28:]
for i in range(16):
key_c = rol(key_c,num[i])
key_d = rol(key_d,num[i])
key_rol = key_c + key_d
key = pc_2(key_rol)
key_list.append(key)
return key_list
def des_en(plaintext,key):
plain_ip = ip(plaintext)
key_list = box_key(key)
plain_left = plain_ip[0:32]
plain_right = plain_ip[32:]
for i in range(15):
plain_temp = plain_right
plain_right_res = fun_f(plain_right,key_list[i])
plain_right = xor(plain_left,plain_right_res)
plain_left = plain_temp
final_right = plain_right
final_left = xor(fun_f(plain_right,key_list[15]),plain_left)
final_text = final_left + final_right
final_text = ip_1(final_text)
return (final_text)
def des_de(cipher,key):
key_list = box_key(key)
cipher = ip(cipher)
cipher_left = cipher[0:32]
cipher_right = cipher[32:]
i = 15
while i>0:
cipher_temp = cipher_right
cipher_right = xor(fun_f(cipher_right,key_list[i]),cipher_left)
cipher_left = cipher_temp
i = i - 1
final_right = cipher_right
final_left = xor(fun_f(cipher_right,key_list[0]),cipher_left)
final_cipher = final_left + final_right
final_text = ip_1(final_cipher)
return (final_text)
def encryption(plain,key):
if len(key)<8:
key += '0'*(8-len(key))
elif len(key)>8:
key = key[0:8]
plain = stob(plain)
key = stob(key)
plain += (64-(len(plain)%64))*'0'
res = ''
for i in range(0,len(plain),64):
Y = plain[i:i+64]
res += des_en(Y,key)
return base64.b64encode(b2s(res))
def decryption(cipher,key):
if len(key)<8:
key += '0'*(8-len(key))
elif len(key)>8:
key = key[0:8]
cipher = base64.b64decode(cipher)
cipher = stob(cipher)
key = stob(key)
res = ''
for i in range(0,len(cipher),64):
Y = cipher[i:i+64]
res += des_de(Y,key)
k = ''
for i in range(0,len(res),8):
if res[i:i+8]!='00000000':
k += chr(int(res[i:i+8],2))
return k
f = 'flag{y0u_found_it!}'
key = '00000000'
b = encryption(f,key)
print "明文：%s\nkey：%s\n加密后的密文：%s\n解密后的明文：%s"%(f,key,encryption(f,key),decryption(b,key))
