MD5: (lsof_4.77.gz) = 9ad25c461c1df603dcebbc1880dd1e40 sum: 48788 237 lsof_4.77.gz You may need to use sum's -r option (or cksum -o1) to get a matching result. Even then the block count may not match, depending on the block size your sum (or cksum) program reports. The sum program that generated the above value considers block size to be 512. The most reliable authentication method is to use GPG with the detached certificate in lsof_4.77.sig -- e.g., $ gpg --verify lsof_4.77.sig lsof_4.77.gz Victor A. Abell Tue Apr 4 16:36:59 EDT 2006 .