def decrypt(ct, k):
# pad the ciphertext using PKCS#7 if needed
if len(ct) % len(k) > 0:
ct = pkcs7_padding(ct, len(ct) + (len(k) - len(ct) % len(k)))
assert len(ct) % len(k) == 0
pt = [0 for i in range(len(ct))]
for i in range(len(ct), len(k), -len(k)):
x = aes_ecb.decrypt(ct[i - len(k) : i], k)
pt[i - len(k) : i] = fxd_xor.fxd_xor(x, ct[i - 2 * len(k) : i - len(k)])
x = aes_ecb.decrypt(ct[0 : len(k)], k)
pt[0 : len(k)] = fxd_xor.fxd_xor(x, [0 for x in range(len(k))]) # using the IV
return pt
def hmming_dist(s, t):
assert len(s) == len(t)
bp = int(binascii.hexlify(bytes(fxd_xor(s, t))), 16)
def f(bp, cnt=0):
if bp == 0: return cnt
if bp & 1 != 0: return f(bp >> 1, cnt +1)
return f(bp >> 1, cnt)
return f(bp)
def crk_1bxor(c, tl=0.98):
lst = []
for b in range(0, 256):
k = [b] * len(c)
_p = fxd_xor(c, k)
p = list(map(lambda x: x+32 if x in range(65,91) else x, _p))
o = dict(zip(range(97,123), [0]*26))
ln = 0
for x in p:
if x in o:
o[x] += 1
ln += 1
elif x in b' \n\r\t\'':
ln += 1
if ln/len(p) < tl: continue
e = dict(map(lambda x: (x[0], x[1]/100*ln), en.items()))
lst.append((chi_sqrd(o, e), _p, k))
lst.sort(key=lambda x: x[00])
return lst
def rpting_xor(s, k):
while len(k) < len(s): k += k
k = k[:len(s)]
return fxd_xor(s, k)
