Sure but that leaks some information about your password. SHA-1 hashes are significantly quicker to compute than a password hash (and rainbow tables exist makin

Sure but that leaks some information about your password. SHA-1 hashes are significantly quicker to compute than a password hash (and rainbow tables exist making it even faster). So the first five characters can be used to narrow the search space. This is however not likely a real problem unless your threat model includes targeted attacks.