Quote:
Originally Posted by onemoretimes
Well considering I've never even seen my private keys, how am I suppose to know if it's low entropy? Couldn't a brute force program be programmed to search in a random fashion, thus all keys are the same likely hood of being found and there is no such thing as low entropy.
I mean, we're talking about a series of digits with a certain number of possibilities. The # of possibilities doesn't change with what letters or numbers you decide to choose.
Your private key is just a (hopefully) random number between 0 and some extremely large number (usually 2^128, with an effective maximum of 2^160, since that is the range of bitcoin addresses). Searching through even a significant part of all possible numbers from 1 to 2^160 is ~impossible.
However, if you choose a number from a way smaller range (e.g. due to a bug in your wallet software), lets say between 0 and 2^64, an attacker that just starts from 1 and moves up will find your key in his first 2^64 tries! (while an attacker who just picks a random 160-bit key every time won't improve his chances).