Checking authenticity of files

1) import my gpg key
   $ gpg --recv-keys --keyserver pgp.mit.edu 75FE0A51

2) Download the file you are interested in and its signature
   $ wget http://download.gna.org/smbldap-tools/packages/smbldap-tools-0.9.3.tgz.sig
   $ wget http://download.gna.org/smbldap-tools/packages/smbldap-tools-0.9.3.tgz

3) Use GnuPG to compare the files
   $ gpg --verify smbldap-tools-0.9.3.tgz.sig