The MD5 hash is 128 bits long. This means that there are 340,282,366,920,938,463,463,374,607,431,768,211,456 values. This means that even if you could try a TRILLION combinations a second it would take you 10,790,283,070,806,014,188 years to break!
A brute force attack against MD5 won't work.
try a distributed attack. use the processing power of every computer on the planet.
Do the calculations.... even a trillion machines (which would about 167 such machines for every person on the earth), each capable of a trillion tests a second, it would still take 10,790,283 years
actually, thinking of it this way, wouldn't it just make sense to create a reverse lookup table of every possible password and its encrypted value.
As for storing the lookup table... creating the lookup table will take as much time as mentioned above... And where ru going to store it? Even if you could store one lookup table entry on one single electron, the storage device (for 10^38 entries) would weigh 10,000 tons.
Regards, Vinay vinay@vinaypai.com