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@SciresM
Last active June 1, 2024 03:36
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import binascii, sys, random, asn1
from fractions import gcd
def extended_gcd(aa, bb):
lastremainder, remainder = abs(aa), abs(bb)
x, lastx, y, lasty = 0, 1, 1, 0
while remainder:
lastremainder, (quotient, remainder) = remainder, divmod(lastremainder, remainder)
x, lastx = lastx - quotient*x, x
y, lasty = lasty - quotient*y, y
return lastremainder, lastx * (-1 if aa < 0 else 1), lasty * (-1 if bb < 0 else 1)
def modinv(a, m):
g, x, y = extended_gcd(a, m)
if g != 1:
raise ValueError
return x % m
def get_primes(D, N, E = 0x10001):
'''Computes P, Q given E,D where pow(pow(X, D, N), E, N) == X'''
assert(pow(pow(0xCAFEBABE, D, N), E, N) == 0xCAFEBABE) # Check privk validity
# code taken from https://stackoverflow.com/a/28299742
k = E*D - 1
if k & 1:
raise ValueError('Could not compute factors. Is private exponent incorrect?')
t = 0
while not k & 1:
k >>= 1;
t += 1
r = k
while True:
g = random.randint(0, N)
y = pow(g, r, N)
if y == 1 or y == N - 1:
continue
for j in range(1, t):
x = pow(y, 2, N)
if x == 1 or x == N - 1:
break
y = x
if x == 1:
break
elif x == N - 1:
continue
x = pow(y, 2, N)
if x == 1:
break
p = gcd(y - 1, N)
q = N // p
assert N % p == 0
if p < q:
p, q = q, p
return (p, q)
def get_pubk(clcert):
'''Ugly extraction of stuff from cert.'''
# (Weakly) Validate input
if 'NintendoNXCA2Prod10' not in clcert:
print('Error: Client Cert is not NintendoNXCA2Prod10.')
sys.exit(1)
clcert_decoder = asn1.Decoder()
clcert_decoder.start(clcert)
clcert_decoder.enter() # Seq, 3 elem
clcert_decoder.enter() # Seq, 8 elem
clcert_decoder.read()
clcert_decoder.read()
clcert_decoder.read()
clcert_decoder.read()
clcert_decoder.read()
clcert_decoder.read()
clcert_decoder.enter()
clcert_decoder.enter()
t, v = clcert_decoder.read()
assert(v == '1.2.840.113549.1.1.1') # rsaEncryption(PKCS #1)
clcert_decoder.leave()
t, v = clcert_decoder.read()
rsa_decoder = asn1.Decoder()
rsa_decoder.start(v[1:])
rsa_decoder.enter()
t, N = rsa_decoder.read()
t, E = rsa_decoder.read()
return (E, N)
def main():
'''Script to create switch der from raw private exponent.'''
# Read files
try:
with open('clcert.der', 'rb') as f:
clcert = f.read()
except:
print('Failed to read Client Cert from clcert.der!')
sys.exit(1)
try:
with open('privk.bin', 'rb') as f:
privk = f.read()
except:
print('Failed to read Private Key from privk.bin!')
sys.exit(1)
if len(privk) != 0x100:
print('Error: Private key is not 0x100 bytes...')
sys.exit(1)
E, N = get_pubk(clcert)
D = int(binascii.hexlify(privk), 0x10)
if pow(pow(0xDEADCAFE, E, N), D, N) != 0xDEADCAFE:
print('Error: privk does not appear to be inverse of pubk!')
sys.exit(1)
print('Found Key: ')
print('E: %X' % E)
print('D: %0512X' % D)
print('N: %0512X' % N)
P, Q = get_primes(D, N, E)
print('P: %0256X' % P)
print('Q: %0255X' % Q)
dP = D % (P - 1)
dQ = D % (Q - 1)
print('dP: %0256X' % dP)
print('dQ: %0256X' % dQ)
Q_inv = modinv(Q, P)
print('Q_inv: %0256X' % Q_inv)
enc = asn1.Encoder()
enc.start()
enc.enter(0x10)
enc.write(0)
enc.write(N)
enc.write(E)
enc.write(D)
enc.write(P)
enc.write(Q)
enc.write(dP)
enc.write(dQ)
enc.write(Q_inv)
enc.leave()
priv_der = enc.output()
try:
with open('privkey.der', 'wb') as f:
f.write(priv_der)
except:
print('Failed to write privkey.der!')
sys.exit(1)
print('Successfully wrote to privkey.der!')
if __name__=='__main__':
main()
# Uncomment if you don't have asn1 installed for python.
# pip install asn1
python switch_cert.py
openssl x509 -inform DER -in clcert.der -outform PEM -out clcert.pem
openssl rsa -inform DER -in privkey.der -outform PEM -out privkey.pem
cat clcert.pem privkey.pem > nx_tls_client_cert.pem
# openssl pkcs12 will prompt for a password for the PKCS#12 cert, but can leave empty
openssl pkcs12 -export -in nx_tls_client_cert.pem -out nx_tls_client_cert.pfx
@xGOBx
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xGOBx commented Jun 1, 2024

I am also looking mariko certificate extraction

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