I havn't heard of the Verdano cipher previously, but if it's only using a "random" use-once key the size of the message, and XORing key+message, it is just a derivation of a one-time-pad, albeit digital.shadowhawk wrote: No, I'm talking about Verdano (?) cipher. The one where the random key is the length of the message, and you encode the message by XORing key and message. But both parties have to have the key, and no one else. And the key should be used only once.
It basicly boils down to this: The security of the cipher is only as secure as your random key generator. The random number generators inside your PC whilst they may seem random - given enough data are fairly predictable.
There are now some random number generators which appear to be truely random - but they require some hardware bits to be added to your PC.