LC4 (nor any other publically known password retreiving software) can do nothing to crack an MD5 hash. There are attacks against MD5 that can make it take not too long (in crypto terms) to crack such as differential cryptanalysis (the T-attack), but no one has yet devised a feasible attack using this against MD5 (at least not to my knowledge). The "easiest" known method would be the birthday attack which can bring it down to roughly 500,000 years. There are probably other attacks that can bring it down further (plus the faster the machine the faster the cracking, i.e. an NSA cryptanalysis computer could do it much faster than the times I'm quoting). But in any case, unless your goal is to use MD5 to prevent anyone (general people, military and intelligence angencies, etc) from getting at your password MD5 is fine. Perhaps in the future mIRC could add support for SHA1 or RIPEMD160 which provides signifigantly stronger hashing abilities.
