verify_digest(){	# $0 method file string
  case "$1" in
  *)
    DIGEST=`echo "$1" | tr a-z A-Z`
    [ "$DIGEST($2)= $3" = "`openssl $1 $2`" ]
    ;;
  esac
}
verify_signature(){	# $0 url|id ... sig
  while [ "$1" != "" ]; do
    case "$1" in
    0x*)
      gpg --recv-keys "$1" || return $?
      ;;
    http:*|ftp:*)
      curl "$1" | gpg --import || return $?
      ;;
    *)
      gpg --verify "$1"
      return $?
    esac
    shift
  done
}
error_out(){	# $0 message ...
  echo "$@" 1>&2
  exit 1
}

wget -N ftp://ftp.gnupg.org/gcrypt/gnupg/gnupg-1.4.9.tar.bz2
wget -N ftp://ftp.gnupg.org/gcrypt/gnupg/gnupg-1.4.9.tar.bz2.sig

#verify_digest md5 gnupg-1.4.9.tar.bz2 cc52393087480ac8d245625004a6a30c || error_out "$0: stopped at line $LINENO"
verify_digest sha1 gnupg-1.4.9.tar.bz2 826f4bef1effce61c3799c8f7d3cc8313b340b55 || error_out "$0: stopped at line $LINENO"

tar xvjf gnupg-1.4.9.tar.bz2