def transformPsi(bl):
"""
Transforms block bl according following rule:
transformP(y16|y15|...|y1)=(y1+y2+y3+y4+y13+y16)|y16|y15|..|y3|y2
"""
y = []
bl_cut = bl
for i in range(16):
y.append(cryptBlocks.getRight(bl_cut, 16, True))
bl_cut = cryptBlocks.cutRight(bl_cut, 16, True)
resBl = 0
leftSide = y[0]^y[1]^y[2]^y[3]^y[12]^y[15]
resBl = cryptBlocks.concat(leftSide, bl>>16, 240)
return resBl
def transformP(bl):
"""
Transforms block bl according following rule:
transformP(y32|y31|...|y1)=yfi(32)|yfi(31)|...|yfi(1)
"""
fi = getFi()
y = []
for i in range(32):
y.append(cryptBlocks.getRight(bl, 8, True))
bl = cryptBlocks.cutRight(bl, 8, True)
resBl = 0
for i in range(1,33):
resBl = cryptBlocks.concat(resBl, y[fi[33-i]-1], 8)
return resBl
def functionF(A, K):
"""
The function f(Ai, Ki). Ai - righ side of the block, Ki - key.
"""
if makeReport:
reporter.addBold(" шаговая функция(%s, %s)"%(hex(A), hex(K)))
# 1. Summing modulo 2^32
# summ = (A + K) % (2**32)
summ = A+K
# 0x100000000 - 2**32
if summ > 0x100000000:
summ = summ - 0x100000000
if makeReport:
reporter.add(" Сумма по модулю 2<sup>32</sup>: "+hex(summ)+"<br>")
# summ = (A+K) - (((A+K)>>32)<<32)
# 2. Replacing S-Box
blocks = []
# splitting by 4 bits. youngest bits will be blocks[0]
for i in range(8):
blocks.append(cryptBlocks.getRight(summ, 4, True))
summ = cryptBlocks.cutRight(summ, 4, True)
# blocks.reverse()
# if makeReport:
# reporter.addList([hex(x) for x in blocks])
# replacing...
blocksReplaced = blocks
if makeReport:
reporter.add(" Заменяем по каждые 4 бита согласно таблице замен (S-box):<br>")
for i in range(8):
if makeReport:
reporter.add(" %d. %s(%d) → %s(%d)<br>"%(i+1, hex(blocks[i]),blocks[i],hex(Sbox[i][blocks[i]]),Sbox[i][blocks[i]]))
blocksReplaced[i] = Sbox[i][blocks[i]]
res = cryptBlocks.getIntegerFromHalfByteArray(blocksReplaced)
if makeReport:
reporter.add(" В результате замены имеем: %s<br>"%(hex(res),))
# 3. Cycle shift 11
res = cryptBlocks.shiftCycleLeft(res, 11,32)
if makeReport:
reporter.add(" Циклический сдвиг влево на 11 бит: %s<br>"%(hex(res),))
return res
def genKeys(key):
"""
Generates key list K1..K32.
Every K_j is 4 bytes(or 32 bit) long.
We would have to just iterate for each K element.
"""
K = []
# K1..K8
key_cut = key
for i in range(8):
K.append(cryptBlocks.getRight(key_cut, 4))
key_cut = cryptBlocks.cutRight(key_cut, 4)
#K9..K24
for j in range(2):
for i in range(8):
K.append(K[i])
#K25..K32
for i in range(8):
K.append(K[7-i])
return K
def stepFunction(Hin, m):
"""
Step function f(Hin, m)
"""
if makeReport:
reporter.addHeader2("stepFunction(%s,%s)"%(hex(Hin), hex(m)))
# step1. generating keys
C2 = 0
C3 = 0xff00ffff000000ffff0000ff00ffff0000ff00ff00ff00ffff00ff00ff00ff00
C4 = 0
U = Hin
V = m
W = U ^ V
K1 = transformP(W)
U = transformA(U)^C2
V = transformA(transformA(V))
W = U ^ V
K2 = transformP(W)
U = transformA(U)^C3
V = transformA(transformA(V))
W = U ^ V
K3 = transformP(W)
U = transformA(U)^C4
V = transformA(transformA(V))
W = U ^ V
K4 = transformP(W)
if makeReport:
reporter.addBold("Generated keys:")
reporter.addList([hex(K1), hex(K2), hex(K3), hex(K4)])
# step2. crypting tranformation
Hin_cut = Hin # we need Hin for the next step, but this step cuts Hin
h1 = cryptBlocks.getRight(Hin_cut, 64, True)
Hin_cut = cryptBlocks.cutRight(Hin_cut, 64, True)
h2 = cryptBlocks.getRight(Hin_cut, 64, True)
Hin_cut = cryptBlocks.cutRight(Hin_cut, 64, True)
h3 = cryptBlocks.getRight(Hin_cut, 64, True)
Hin_cut = cryptBlocks.cutRight(Hin_cut, 64, True)
h4 = cryptBlocks.getRight(Hin_cut, 64, True)
Hin_cut = cryptBlocks.cutRight(Hin_cut, 64, True)
s1 = gost28147.cryptBlock(h1, K1)
s2 = gost28147.cryptBlock(h2, K2)
s3 = gost28147.cryptBlock(h3, K3)
s4 = gost28147.cryptBlock(h4, K4)
S = s4
S = cryptBlocks.concat(S, s3, 64)
S = cryptBlocks.concat(S, s2, 64)
S = cryptBlocks.concat(S, s1, 64)
if makeReport:
reporter.addBold("Crypting transformation:")
reporter.addList([
"gost28147(%s,%s)=%s"%(hex(h1),hex(K1),hex(s1)),
"gost28147(%s,%s)=%s"%(hex(h2),hex(K2),hex(s2)),
"gost28147(%s,%s)=%s"%(hex(h3),hex(K3),hex(s3)),
"gost28147(%s,%s)=%s"%(hex(h4),hex(K4),hex(s4)),
])
reporter.addBold("S="+hex(S))
# Step 3. Shuffle transforming.
Hout = transformPsi(S)
for i in range(12):
Hout = transformPsi(Hout)
Hout = transformPsi(Hout ^ m)^Hin
for i in range(61):
Hout = transformPsi(Hout)
return Hout
