Method defined by the American Department of Defense. Data is erased by writing Bit patterns to all physical sectors of the device and consists of 4 steps:
1: Overwrite all sectors of the disk with the binary pattern “00”;
2: Overwrite all sectors of the disk with their binary complement, i.e. “11”;
3: Overwrite all sectors on the disk with random binary patterns.
4: Verification of the random overwrite performed in the last process, confirming safe and permanent erasure of the data.