void sum_init(int csum_type, int seed)
{
	char s[4];

	if (csum_type < 0)
		csum_type = parse_csum_name(NULL, 0);
	cursum_type = csum_type;

	switch (csum_type) {
	  case CSUM_MD5:
		md5_begin(&md);
		break;
	  case CSUM_MD4:
		mdfour_begin(&md);
		sumresidue = 0;
		break;
	  case CSUM_MD4_OLD:
	  case CSUM_MD4_BUSTED:
	  case CSUM_MD4_ARCHAIC:
		mdfour_begin(&md);
		sumresidue = 0;
		SIVAL(s, 0, seed);
		sum_update(s, 4);
		break;
	  case CSUM_NONE:
		break;
	}
}

The product does not validate or incorrectly validates the integrity check values or checksums of a message. This may prevent it from detecting if the data has been modified or corrupted in transmission.