Spectrum Scale has support for end-to-end checksumming if you have an ESS, but not with non-ESS storage. As a poor man's checksumming, one can store file checksums in the extended attributes. Storing checksums here can be useful for validating if there has been bitrot at a later point, without leaving around .md5sum-files everywhere. Manually this can be done with the “mmchattr” command:
Starting with OpenSSH v3.9 there was a new feature that allowed one to run several sessions over the same ssh connection. The benefit of connection sharing is that only the first time you connect to a host you'll need to exchange keys, authenticate, negotiate encryption, etc. Skipping all this initial connection setup, makes any additional sessions to a host you've already connected to very quick.
Here's a port of http://www.cs.umd.edu/users/harry/jotp/ to Java 2 Platform Micro Edition (J2ME), so that it can be used on mobile phones that supports Java. I made this so that I can securely connect to our ssh-server from insecure internet cafees, where people might be trying to sniff my passsword. The midlet supports md5-hashing, since that's what I'm using. Adding md4 should be trivial, if anybody needs it.
I've wanted to know the cputime used in java functions, but it turned out that this was a bit too low level for java. Therefore I had to create a JNI (Java Native Interface) function for it. The code for this example is at http://tanso.net/CPUtest.tar.gz , and here's how to do it: