The binaries in this directory are dynamically linked and should work on redhat9 linux systems, and perhaps other linux systems. If it doesn't work for you get the static linked binaries from the other directory. The .tgz file is a tgz file suitable for untarring in / as root. It contains the two executables installed in usr/local/bin and the hashcash man page installed in usr/man/man1/hashcash.1 The .asc files are signatures on the other objects.