ALL the CTFS of Crypto2025 finally

crypto-asimmetric/RSA-1/rsa_1.py

@@ -0,0 +1,41 @@
+from Cryptodome.Util.number import bytes_to_long, getPrime
+#from secret import flag
+def egcd(a, b):
+    if (a == 0):
+        return (b, 0, 1)
+    else:
+        g, y, x = egcd(b%a, a)
+        return (g, x - (b//a) * y, y)
+
+e = 65537
+
+"""p, q = getPrime(64), getPrime(64)
+n = p*q
+e = 65537
+print(n)
+m = bytes_to_long(flag)
+print(pow(m, e, n))"""
+
+#p = 14364722473065221639
+#q = 12271643243945501447
+
+p =  88824237363878748201253577036
+q = 866961515596671343895614356197
+
+n = p*q
+phi = (p-1)*(q-1)
+res = egcd(e, phi)
+
+#c = 46228309104141229075992607107041922411
+
+c = 388435672474892257936058543724812684332943095105091384265939
+u = res[1]
+v = res[2]
+
+decrypted = pow(c,u,n)
+
+print(decrypted.to_bytes(decrypted.bit_length()//8+1,byteorder='big').decode())
+#P20 = 14364722473065221639
+#P20 = 12271643243945501447
+# 176278749487742942508568320862050211633
+# 46228309104141229075992607107041922411