  This paper introduces and demonstrates two new attacks against the
Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange scheme. The attacks are
based on random number generators with compromised security. First we explore
the situation in which Eve knows the seed of both Alice's and Bob's random
number generators. We show that in this situation Eve can crack the secure key
bit within a fraction of the bit exchange period even if her current and
voltage measurements have only a single bit of resolution. In the second
attack, we explore the situation in which Eve knows the seed of only Alice's
random number generator. We show that in this situation Eve can still crack the
secure key bit but she needs to use the whole bit exchange period for the
attack. The security of the KLJN key exchange scheme, similarly to other
protocols, necessitates that the random number generator outputs are truly
random for Eve.
