Changes

This reduces the effective length of the hash to the number of bytes before the NULL byte. This means that the difficulty of finding a hash collision is reduced from 2^(HASHLENGTH*8) to 2^(bytes before the null). That is a big change if the NULL is early in the hash. Assuming the NULL is at the 5th byte, that means that there is a one in 2^(4*8) chance that the hash matches, or one in 4 294 967 296, fairly computable within a reasonable time frame on a current computer that can try a few million hash inputs each sec.

This reduces the effective length of the hash to the number of bytes before the NULL byte. This means that the difficulty of finding a hash collision is reduced from 2^(HASHLENGTH*8) to 2^(bytes before the null). That is a big change if the NULL is early in the hash. Assuming the NULL is at the 5th byte, that means that there is a one in 2^(4*8) chance that the hash matches, or one in 4 294 967 296, fairly computable within a reasonable time frame on a current computer that can try a few million hash inputs each sec.