Introdution

Sanitize features provide standardized, secure, and verifiable methods to irreversibly erase all user data stored on SSDs, including areas that are not accessible through regular deletion or formatting. Sanitize commands are defined in both the NVMe and SATA specifications. For PCIe SSDs, they are specified in the NVMe standard; for SATA SSDs, they are defined in the ATA specification by the T13 Technical Committee.

Unlike ordinary file deletion or a quick format, Sanitize commands target all storage areas, including: User addressable space, Over-provisioned blocks, Spare and remapped blocks. Once the Sanitize operation is initiated, it will automatically resume and complete even if a power interruption occurs. This is a key distinction from other erase commands, ensuring the reliability of data destruction.

Sanitize Methods generally refer to three standardized techniques defined in the major specifications: 

Block Erase

Block Erase performs a low-level operation that resets each NAND flash memory block to an erased state. SSD issues erase commands to every physical block, setting all previously written data back to the “1” state (erased). This process covers both user data and internal reserved areas. SP Industrial Block Erase typically takes several minutes to tens of minutes, depending on drive capacity. This method is often used when a device is being decommissioned and no encryption is enabled, or when a full physical reset of all NAND cells is required.

Overwrite

Overwrite writes a specific data pattern to every accessible and inaccessible block. SSD first erases the blocks, then writes the defined pattern over all of them. This process is repeated in multiple passes to provide a higher level of assurance that no residual data remains. Overwrite is slower than Block Erase, as it requires both erase and write cycles.

Cryptographic Erase

Cryptographic Erase (CE) invalidates data by destroying the encryption key used to protect all stored information. SSDs with hardware encryption (Self-Encrypting Drives, or SEDs) use AES-256 to transparently encrypt all data. When Cryptographic Erase is triggered, the drive either deletes or regenerates the encryption key, rendering all previously encrypted data permanently unreadable. Cryptographic Erase executes extremely quickly. Industrial SSDs can use multi-channel erase techniques to sanitize a 1TB pSLC SSD in around 10 seconds. —and does not require any physical overwriting or erasure of NAND blocks.