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On-drive encryption serves to allow for secure erase which would otherwise require an entire write cycle and cannot be done at an OS level anyway due to wear le

On-drive encryption serves to allow for secure erase which would otherwise require an entire write cycle and cannot be done at an OS level anyway due to wear leveling and reserved space. It is not intended for providing privacy or security.

neodymiumphish 3y ago
Is secure erase reliable? If so, how can you say the intent of the encryption isn't security?
- SAI_Peregrinus 3y ago
  Secure erase via sledgehammer is pretty reliable.
- supertrope 3y ago
  It depends on your threat model. Just enabling BitLocker will defeat someone from plugging in a Linux live USB and resetting your Windows password. For corporate security ATA Secure Erase done by a vendor who accepts liability and gives them a "certificate of data destruction" may be enough to meet HIPAA, FERPA, SOX compliance requirements. Or they consider drives cheap enough that physically shredding them to ensure no mistakes is the better choice. At the national security level you pulverize the drives after zeroing them, likely in a windowless room inside a facility with armed guards.
  - neodymiumphish 3y ago
    As one who's actually had the pleasure of getting to use one of the classified drive destroyers, there aren't armed guards. Not sure if there's a requirement that it be done in a room with no windows, though. My point was that Kenny's claim is that on-drive encryption allows for easier "erasure", presumably by deleting the keys needed to decrypt the data and leaving the drive in the same state. If that process is good enough to ensure proper "erasure" of the data (effectively complete prevention of data access), then how is it not equally secure as an encryption schema?
Detrytus 3y ago
Secure erase works on assumption that encrypted data is indistinguishable from random noise AND that attacker cannot recover the encryption key. Insecure implementations of encryption will leave some way to recover/reverse engineer the key, which means they are useless for secure erase as well.

neodymiumphish 3y ago

Is secure erase reliable? If so, how can you say the intent of the encryption isn't security?

SAI_Peregrinus 3y ago
Secure erase via sledgehammer is pretty reliable.
supertrope 3y ago
It depends on your threat model. Just enabling BitLocker will defeat someone from plugging in a Linux live USB and resetting your Windows password. For corporate security ATA Secure Erase done by a vendor who accepts liability and gives them a "certificate of data destruction" may be enough to meet HIPAA, FERPA, SOX compliance requirements. Or they consider drives cheap enough that physically shredding them to ensure no mistakes is the better choice. At the national security level you pulverize the drives after zeroing them, likely in a windowless room inside a facility with armed guards.
- neodymiumphish 3y ago
  As one who's actually had the pleasure of getting to use one of the classified drive destroyers, there aren't armed guards. Not sure if there's a requirement that it be done in a room with no windows, though. My point was that Kenny's claim is that on-drive encryption allows for easier "erasure", presumably by deleting the keys needed to decrypt the data and leaving the drive in the same state. If that process is good enough to ensure proper "erasure" of the data (effectively complete prevention of data access), then how is it not equally secure as an encryption schema?

Detrytus 3y ago

Secure erase works on assumption that encrypted data is indistinguishable from random noise AND that attacker cannot recover the encryption key. Insecure implementations of encryption will leave some way to recover/reverse engineer the key, which means they are useless for secure erase as well.