Adding the common modulus attack script

Author: a0xnirudh

Diff for: RSA Attacks/RSA: Common modulus attack.py

@@ -0,0 +1,69 @@
+ #!/usr/bin/python3.4
+   # Written by Anirudh Anand (lucif3r) : email - [email protected]   
+   # This program will help to decrypt cipher text to plain text if you have
+   # more than 1 cipher text encrypted with same Modulus (N) but different
+   # exponents. We use extended Euclideangm Algorithm to achieve this.
+   
+   __author__ = 'lucif3r'
+   
+   import gmpy2
+   
+   
+   class RSAModuli:
+       def __init__(self):
+           self.a = 0
+           self.b = 0
+           self.m = 0
+           self.i = 0
+       def gcd(self, num1, num2):
+           """
+           This function os used to find the GCD of 2 numbers.
+           :param num1:
+           :param num2:
+           :return:
+           """
+           if num1 < num2:
+               num1, num2 = num2, num1
+           while num2 != 0:
+               num1, num2 = num2, num1 % num2
+           return num1
+       def extended_euclidean(self, e1, e2):
+           """
+           The value a is the modular multiplicative inverse of e1 and e2.
+           b is calculated from the eqn: (e1*a) + (e2*b) = gcd(e1, e2)
+           :param e1: exponent 1
+           :param e2: exponent 2
+           """
+           self.a = gmpy2.invert(e1, e2)
+           self.b = (float(self.gcd(e1, e2)-(self.a*e1)))/float(e2)
+       def modular_inverse(self, c1, c2, N):
+           """
+           i is the modular multiplicative inverse of c2 and N.
+           i^-b is equal to c2^b. So if the value of b is -ve, we
+           have to find out i and then do i^-b.
+           Final plain text is given by m = (c1^a) * (i^-b) %N
+           :param c1: cipher text 1
+           :param c2: cipher text 2
+           :param N: Modulus
+           """
+           i = gmpy2.invert(c2, N)
+           mx = pow(c1, self.a, N)
+           my = pow(i, int(-self.b), N)
+           self.m= mx * my % N
+          def print_value(self):
+           print("Plain Text: ", self.m)
+   
+   
+   def main():
+       c = RSAModuli()
+       N  =
+       c1 =
+       c2 =
+       e1 =
+       e2 =
+       c.extended_euclidean(e1, e2)
+       c.modular_inverse(c1, c2, N)
+       c.print_value()
+    
+   if __name__ == '__main__':
+       main()