That's an amateurish problem that only happens with custom implementations of ECDSA. You have to use a random number when calculating the signature, and every basic implementation of ECDSA guarantees this (at least to the extent of the randomness it can pull from your system). The problem there was people hand-rolling their own and not realizing that reusing "random" numbers when signing different messages with the same key reveals the private key.
This was the same reason that Sony's PS3 signing key was compromised:
https://groups.google.com/forum/#!topic/sci.crypt/3isJl28Slrw
Each key (for each different type of loader) seems to have an
associated random number m the numbers follow no pattern, but they
are consistent between different signatures on different versions of the
same loader almost as if they treated m as one of the parameters of
the key.
If I understand correctly this means Sony decided they were smart enough
to reimplement their own version of ECDSA from scratch.
Famous last word.
Armory is unaffected. And for reference, you don't even need
good random numbers for it. You just need anything that changes between signatures and looks random.
Thank you very much for that information! I really trust your wallet and I love it that you are really caring about a good implementation and testing etc of your wallet!