hash - Is it more safe to modify MD5 output? -

as ordinary method, used save md5 of passwords in database while there many websites decode md5 hashed data original data (using rainbow database).

i wonder if more safe modify output of md5 function (e.g. omitting last character of md5 output create new hashed data)? or there logic behind md5 makes more safe every modified version?

no doesn't make passwords more secure. adds bit of "security obscurity", when hash passwords, prepare case attacker knows hashes , algorithm.

the problem md5 in general , derivations is, can calculated ways fast. common hardware can calculate 8giga md5/s, makes brute-forcing easy. todays password cracker tools not offer plain md5 hashes, can calculate derivations, e.g. md5(strtoupper(md5($pass))) out of box.

for secure storing of passwords need slow hash function bcrypt, pbkdf2 or scrypt cost factor. of course should salted unique salt per password.