A lot of data wipe algorithms have the final wiping pass with random characters. They discuss about verification after the wipe. An example of this is from this link:
That brings up this question:
When you view the dump in the first few sectors, you see a lot of non-sensical characters but how do you know that it's truly random or may contain potential information? How does the verification process work? I don't see how you can verify when every byte is random, it has to be a consistent pattern where you can establish verification, right?