Checking the MD5 Digest

Checking the MD5 digest value is easy if you're on a UNIX system. Most of the modern systems now have a command md5sum. Md5sum computes the MD5 digest value for the file name entered at the command line. Thus, you check the digest of the recent OpenSSL distribution with the following command:

bash-2.05$ md5sum openssl-0.9.7-beta4.tar.gz
43cf89b428fbdd7873b5aae2680cd324  openssl-0.9.7-beta4.tar.gz

The output of MD5sum is the 128-byte MD5 digest in hexadecimal of the file, or files, you entered on the command line. You must check that value with the value that would be contained in openssl-0.9.7-beta4.tar.gz.md5. The two values should be identical. If you're lazy and are familiar with the UNIX command line, you can also do:

md5sum TARBALL | awk '{print $1;}' | cmp - TARBALL.md5

If you don't get any output from the above command, then the digests match.

    Part II: The Design of Wi-Fi Security