>I believe he may be talking about the SYS(2007) checksum function in VFP. Although I have used this function to compare strings (even cursors with additional manipulation) I don't know what algorithm it uses. I was told by someone ??? that it was a CRC checksum, but anyhow, probally cannot be reversed.

The same applies. It gives you a number (probably a two bytes integer), no matter your expression is 10 bytes or 200 Kb. It obviously can't be reversed.

Of course, my example was extremely simple, but the same principles applies here.

See you.