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decryption.py
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decryption.py
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def dec_init_per_pt(s):
per = [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,
56, 48, 40, 32, 24, 16, 8, 0,
58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6]
value=len(s)*'0'
value=list(value)
for i in range(0,len(per)):
value[per[i]]=s[i]
t=""
for i in value:
t=t+i
return t
def sub_box(s):
r=""
sbox= [[[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(0,8):
t=s[(i*6) : (i*6)+6]
row=str(t[0])+str(t[5])
column=t[1:5]
row=int(row,2)
column=int(column,2)
value=sbox[i][row][column]
value=bin(int(value)).replace("0b", "")
value=str(value)
value=((4-len(value))*'0')+value
r=r+value
return(r)
def permi(s):
value=""
table = [ 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 table:
value+=s[i-1]
return value
def init_per_key(s):
value=""
table = [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 table:
value+=s[i-1]
return value
def exp_per_pt(s):
value=s[31]+s[0:4]+s[4]
for i in range(1,7):
value=value+s[(i*4)-1] + s[(i*4) : (i*4)+4] + s[(i*4)+4]
value= value + s[27] + s[28 :] + s[0]
return(value)
def xor(v1,v2):
res=""
i=0
while(i<len(v1)):
if(v1[i]==v2[i]):
res+="0"
else:
res+="1"
i+=1
return(res)
def pc2(s):
value=""
table = [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 table:
value+=s[i-1]
return(value)
def leftshift(s):
value=s[1:]+s[0]
return value
def hexa(s):
res=""
k=""
x=""
alpha={'0':"0000",'1':"0001",'2':"0010",'3':"0011",
'4':"0100",'5':"0101",'6':"0110",'7':"0111",
'8':"1000",'9':"1001",'A':"1010",'B':"1011",
'C':"1100",'D':"1101",'E':"1110",'F':"1111"}
for i in range(0,len(s),4):
k=s[i:i+4]
x=[number for number,name in alpha.items() if name==k]
res+=str(x)
return(res[2:100:5])
def inverse_permutation(s):
value=''
table = [ 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 ]
value="0"*len(s)
value=list(value)
for i in range(len(table)):
value[table[i]-1]=s[i]
t=""
for i in value:
t=t+str(i)
return t
'''
for i in table:
value+=s[i-1]
return(value)'''
alpha={'0':"0000",'1':"0001",'2':"0010",'3':"0011",
'4':"0100",'5':"0101",'6':"0110",'7':"0111",
'8':"1000",'9':"1001",'A':"1010",'B':"1011",
'C':"1100",'D':"1101",'E':"1110",'F':"1111"}
plainText='C0B7A8D05F3A829C'#input("Enter the Plain Text :")
key="AABB09182736CCDD"#input("Enter the key :")
if(plainText.islower()):
plainText=plainText.upper()
if(key.islower()):
key=key.upper()
constant=0
for i in plainText:
if((ord(i)>=65)and(ord(i)<=70)):
constant=1
#if its a value greater than 65
#I'll fill this
#print(plainText)
l1=[]
i=0
while i<len(plainText):
x=plainText[i]
i=i+1
l1.append(alpha[x])
s1=""
i=0
while(i<len(l1)):
y=str(l1[i])
s1+=y
i=i+1
#print(key)
l2=[]
i=0
while i<len(key):
x=key[i]
i=i+1
l2.append(alpha[x])
s2=""
i=0
while(i<len(l2)):
y=str(l2[i])
s2+=y
i=i+1
#print(l1)
key1=s2;
keyvalues=[]
#initial key Permutation
key2=init_per_key(key1)
C0=""
D0=""
C1=""
D1=""
for iii in range(1,17):
#dividing the C0 and D0
C0=key2[0:28]
D0=key2[28:56]
C1=leftshift(C0)
D1=leftshift(D0)
C1=leftshift(C1)
D1=leftshift(D1)
if(iii==1 or iii==2 or iii==9 or iii==16):
C1=leftshift(C0)
D1=leftshift(D0)
per2_key=""
per2=""
per2_key=C1+D1
key2=per2_key
per2=pc2(per2_key)
keyvalues.append(per2)
key2=per2_key
keyvalues=keyvalues[::-1]
inti_text=inverse_permutation(s1)
for i in range(0,16):
left=inti_text[0:32]
right=inti_text[32:]
print("l0 " +hexa(left))
print("r0 "+hexa(right))
print("key "+hexa(keyvalues[i]))
R0=right
ex=exp_per_pt(R0)
kw4=""
kw4=xor(ex,keyvalues[i])
kw5=""
kw5=sub_box(kw4)
kw6=""
kw6=permi(kw5)
l1=xor(kw6,left)
inti_text=R0+l1
inti_text=inti_text[32:64]+inti_text[0:32]
print(hexa(inti_text))
pt=dec_init_per_pt(inti_text)
print(hexa(pt))