I know that I wipe a USB drive from Linux by douing a "dd" overwriting the whole device with random data. This however may take very long time.

Is it possible to do this faster (and still safe), by asking the drive to erase all unused space. That is activate the flash erase process.

Edit: What I'm looking for is a way to do the electrical erase of all block in the flash. Blocks set aside for wearleveling should also be possible to erase.

Perhaps SD cards has better features for this.