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Copy pathcipher1.py
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80 lines (57 loc) · 2.14 KB
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# coding: utf-8
__author__ = 'igogor'
import hashlib
def hash_long(message):
hash_ = long(hashlib.sha256(message).hexdigest(), base=16)
print 'hash({}): {}'.format(message, hash_)
return hash_
R_CONST = hash_long('asdfasdfasdfasdfasdf')
S_LIST = (hash_long('sdfdfalsdofiqjer'), hash_long('adfasdoqwer;lkqner;qwe'), hash_long('adlqoei;landlna'))
MESSAGES = ('11', '22', '33')
HASHES = [hash_long(message) for message in MESSAGES]
MAX_64 = long('f' * 64, base=16)
def extended_gcd(aa, bb):
lastremainder, remainder = abs(aa), abs(bb)
x, lastx, y, lasty = 0, 1, 1, 0
while remainder:
lastremainder, (quotient, remainder) = remainder, divmod(lastremainder, remainder)
x, lastx = lastx - quotient * x, x
y, lasty = lasty - quotient * y, y
return lastremainder, lastx * (-1 if aa < 0 else 1), lasty * (-1 if bb < 0 else 1)
def modinv(a, m):
g, x, y = extended_gcd(a, m)
if g != 1:
raise ValueError
return x % m
def genmod():
for n in range((R_CONST + 1), R_CONST + 1000, 1):
# todo дят плейн вронг
m1 = modinv(S_LIST[1] - S_LIST[0], n)
m2 = modinv(S_LIST[2] - S_LIST[1], n)
if m1 and m2 and m1 == m2:
print 'n = {}'.format(n)
yield n
def calc_k(s1, s2, z1, z2, n):
k = ((z2 - z1) * modinv(s2 - s1, n)) % n
print 'k = {}'.format(k)
return k
def calc_dA(s, k, z, r, n):
dA = ((s * k - z) * modinv(r, n)) % n
print 'dA = {}'.format(dA)
return dA
def calc_s(k, dA, z, r, n):
s = (modinv(k, n) * (z + r * dA)) % n
print 's = {}'.format(s)
return s
def calc_r():
raise NotImplementedError
def calc_main():
for n in genmod():
k = calc_k(s1=S_LIST[0], s2=S_LIST[1], z1=HASHES[0], z2=HASHES[1], n=n)
dA = calc_dA(s=S_LIST[0], k=k, z=HASHES[0], r=R_CONST, n=n)
if S_LIST[2] == calc_s(k=k, dA=dA, z=HASHES[2], r=R_CONST, n=n):
s_getflag = calc_s(k=k, dA=dA, z=hash_long('GETFLAG'), r=R_CONST, n=n)
print 'getflag s: {}'.format(s_getflag)
print 'signature: (r={}, s={})'.format(hex(R_CONST), hex(s_getflag))
break
calc_main()