Blancco Driver Eraser user can select the level of verification of the erasure. The verification process reads data at identical intervals across the whole drive's surface and makes sure that the erasure's overwriting patterns were written correctly. The minimum verification corresponds to checking 1% of the surface of the drive (fast process), while the full verification corresponds to checking 100% of the surface of the drive (slower process).
Taking samples at identical intervals across the drive's surface can efficiently detect any problems in the erasure, while being faster than reading all the overwritten data. Blancco Driver Eraser user can increase the level of verification from the default 1% all the way up to 100% (full verification) when higher level of security is required. If the verification finds any data left on the drive (overwriting patterns are missing), it will alert the user that the erasure process has failed.
A systematic verification step is always enforced after the last overwriting pass.