Update rsa.py

LabMD_2/rsa.py

@@ -1 +1,62 @@
 
+def gcd(x, y):
+    if x > y:
+        small = y
+    else:
+        small = x
+    for i in range(1, small + 1):
+        if (x % i == 0) and (y % i == 0):
+            gcd = i
+    return gcd
+
+
+def is_coprime(a, b):
+    if gcd(a, b) == 1:
+        return 1
+    return 0
+
+
+def get_modular_inverse(a, m):
+    for x in range(1, m):
+        if ((a % m) * (x % m)) % m == 1:
+            return x
+    return 0
+
+
+def get_e(p, q):
+    for x in range(2, phi):
+        if is_coprime(x, phi):
+            return x
+    return "Error"
+
+
+# Starting data
+decrypted = 95384
+p = 281
+q = 283
+n = p * q
+phi = (p - 1) * (q - 1)
+
+# Calculated data
+e = get_e(p, q)
+d = get_modular_inverse(e, phi)
+encrypted = pow(decrypted, e) % n
+decrypted = pow(encrypted, d) % n
+
+# Output
+print("=================")
+print("Public key:")
+print((n, e))
+print("=================")
+print("Private key:")
+print((n, d))
+print("=================")
+print("Initial message:")
+print(decrypted)
+print("=================")
+print("Encrypted message:")
+print(encrypted)
+print("=================")
+print("Decrypted message:")
+print(decrypted)
+print("=================")