-often never read entirely hence the md5s can not be properly computed,
-(2) computing XOR of the first 4, 16 and 256 bytes with rejection as
-soon as one does not match, (3) reading parts of the files of
-increasing sizes so that rejection could be done with a small fraction
+often not read entirely, hence the md5s can not be properly computed,
+(2) computing XORs of the first 4, 16 and 256 bytes with rejection as
+soon as one does not match, (3) reading files in parts of increasing
+sizes so that rejection could be done with only a small fraction read