rsa_corrupted_key.py

#!/usr/bin/python

import pyasn1.codec.der.encoder
import pyasn1.type.univ
import base64

# present values on key.pem 
e = 0x010001
n = 0xC4B07FEFC8E36C05C0DA434221AEBF47DBF70E5189AD892408F3AD81182A9E0700A07C9D7C66C86C7A39602123EE0F605613DE97FDE49FE68396EE0AF3F5F5F3
p = 106173580239682931389627142547722999257831171755485751420548914984291463023277
q = 97024725573258981352721169214486148772531836683230815123426383547032318244639


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)


def modinv(a, m):
    gcd, x, y = egcd(a, m)
    if gcd != 1:
        return None
    else:
        return x % m

# we need to recover this values on private key
dp = modinv(e, (p - 1))
dq = modinv(e, (q - 1))
qi = modinv(q, p)
phi = (p - 1) * (q - 1)
d = modinv(e, phi)


def generate_pem(n, e, d, p, q, dP, dQ, qInv):
    template = '-----BEGIN RSA PRIVATE KEY-----\n{}-----END RSA PRIVATE KEY-----\n'
    seq = pyasn1.type.univ.Sequence()
    for x in [0, n, e, d, p, q, dP, dQ, qInv]:
        seq.setComponentByPosition(len(seq), pyasn1.type.univ.Integer(x))
    der = pyasn1.codec.der.encoder.encode(seq)
    return template.format(base64.encodestring(der).decode('ascii'))

key = generate_pem(n, e, d, p, q, dp, dq, qi)
key
f = open("somevalid.key", "w")
f.write(key)
f.close()