123 lines
2.7 KiB
Python
Executable File
123 lines
2.7 KiB
Python
Executable File
#!/usr/bin/env python3
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# -*- coding: UTF-8 -*-
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import math
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def is_prime(num):
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if isinstance(num, str):
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num = int(num)
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if num in [2, 3, 5]:
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return True
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if num & 1 and num % 5 > 0:
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for i in range(2, math.floor(math.sqrt(num)) + 1):
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if i & 1 and (num % i) == 0:
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return False
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return True
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return False
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def rev(num): # or int(str(num)[::-1])
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if isinstance(num, str):
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num = int(num)
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revs = 0
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while (num > 0):
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remainder = num % 10
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revs = (revs * 10) + remainder
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num = num // 10
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return revs
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def is_emirp(num):
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return is_prime(rev(num))
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def power(x, y, p):
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res = 1
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x %= p
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while (y > 0):
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if (y & 1):
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res = (res * x) % p
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y = y >> 1
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x = (x * x) % p
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return res
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def sqrtNormal(n, p):
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n %= p
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for x in range(2, p):
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if ((x * x) % p == n):
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return x
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return None
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# Assumption: p is of the form 3*i + 4 where i >= 1
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def sqrtFast(n, p):
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if (p % 4 != 3):
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# raise ValueError('Invalid Input')
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return sqrtNormal(n, p)
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# Try "+(n ^ ((p + 1)/4))"
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n = n % p
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x = power(n, (p + 1) // 4, p)
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if ((x * x) % p == n):
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return x
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# Try "-(n ^ ((p + 1)/4))"
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x = p - x
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if ((x * x) % p == n):
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return x
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return None
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def elliptic_curve(x, a, b, r):
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y2 = (x ** 3 + a * x + b) % r
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y = sqrtFast(y2, r) if y2 > 0 else 0
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if y is None:
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return None, None
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return y, -y % r
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AFFINE_INV = None
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def affine_inverse(s, n=29):
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def fn(s, n):
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g = [n, s]
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u = [1, 0]
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v = [0, 1]
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y = [None]
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i = 1
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while g[i] != 0:
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y.append(g[i - 1] // g[i])
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g.append(g[i - 1] - y[i] * g[i])
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u.append(u[i - 1] - y[i] * u[i])
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v.append(v[i - 1] - y[i] * v[i])
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i += 1
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return v[-2] % n
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global AFFINE_INV
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if AFFINE_INV is None:
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AFFINE_INV = [fn(x, n) for x in range(n)]
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return AFFINE_INV[s]
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def affine_decrypt(x, key, n=29): # key: (s, t)
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return ((x - key[1]) * affine_inverse(key[0], n)) % n
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def autokey_reverse(data, keylen, pos, search_term):
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ret = [29] * keylen
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for o in range(len(search_term)):
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plain = search_term[o]
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i = pos + o
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while i >= 0:
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plain = (data[i] - plain) % 29
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i -= keylen
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ret[i + keylen] = plain
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return ret
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if __name__ == '__main__':
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alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
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cipher = 'YDIDWYASDDJVAPJMMBIASDTJVAMD'
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indices = [affine_decrypt(alphabet.index(x), (5, 9), 26) for x in cipher]
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print(''.join(alphabet[x] for x in indices))
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