How can address' hash160 be used to determine information for malicious purposes? (Ie reusing of the same address)
If your PRNGs are good, you don't lose any security by using the same address any number of times. Some websites claim that addresses should not be reused because that will make your bitcoins vulnerable to quantum computers and/or some newly discovered weaknesses in ECDSA. However, both of these scenarios are unrealistic at the moment, and I think that if they do become realistic, this will be such a big problem for the world's cryptography that you won't be the first victim (unless you are Satoshi Nakamoto).