string length

How can I break hash if string length more than 20 characters (up to 30 or even more)?

Hi Gauss. The maximum length of the string is 19 characters; this is for speed reasons. It is extremely unlikely that a message of anywhere near that length could be cracked in a reasonable amount of time (on a modern computer it would probably take years). Raising the limit would cause the hashing process to be slower because of the design of the MD5 hashing algorithm (more characters mean more memory accesses for each hash calculation), therefore the limit is 19 characters. However, by request we could release a custom version for you that would raise the limit to a higher length.

Can You do the option - "pattern of string"? For examle I know that 10 first characters are digits and other 15 is the mix of letters and characters.

This sounds like a good idea, but in the end I think it may be counterintuitive. It would greatly complicate the hash breaking algorithm by adding quite a bit of logic to the core of the program. We'll consider it more thoroughly before we make a final decision, though.