[dan000892]

dd's destruction is gated by the device's write performance and so data may be recoverable if the operation is interrupted.

For those of us with SSDs that transparently leverage AES encryption, the following generates a new keypair and marks all cells as empty instantly nuking it (and restoring the device's write performance to factory-fresh):

  # hdparm --user-master u --security-set-pass p /dev/sdX; hdparm --user-master u --security-erase-enhanced p /dev/sdX

More info on the ATA Secure Erase instruction and how to tell if your storage device supports it can be found here: https://ata.wiki.kernel.org/index.php/ATA_Secure_Erase