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A message, m is encrypted using a private key d.

p = prime()
q = prime()
e = 65537
c = pow(m, e, n)
PHI = (p-1)*(q-1)
d = mod_inverse(e, PHI) 

Assume all these values are known to the attacker, except for the message (m) and ciphertext (c).

Is it possible to find an alternate value for d such that:

c ^ d_alternative % n == m (the ciphertext decrypts correctly to the message)

And

d_alternative % PHI != d (the new d modulus PHI does not equal the old d)

This second part is the catch: d and d_alternative cannot be modularly congruent.

Is this possible, and if so, how?

retep
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