File-based encryption (FBE)
Definition
An Android encryption model introduced in Android 7.0 in which each file is encrypted with a separate key derived from the user credential. FBE replaced full-disk encryption (FDE) on most devices from Android 10 onward. Under FBE, even chip-off acquisition of unallocated blocks yields ciphertext that cannot be decrypted without the per-file key.
Related terms
- Bootloader
- Firmware that runs immediately after power-on to verify, load, and hand control to the operating system. A locked bootloader refuses to execute...
- Chip-off acquisition
- A physical extraction method in which the flash memory chip is desoldered from the device's circuit board and read directly with specialised...
- EDL mode (Emergency Download mode)
- A Qualcomm diagnostic protocol embedded in the Primary Boot Loader (PBL) that activates before the main OS and accepts raw memory read...
- Full-disk encryption (FDE)
- A storage protection model in which the entire partition is encrypted with a key derived from the user's passcode and hardware-bound identifiers....
- NAND flash
- The type of non-volatile memory used in all modern mobile device storage. Data is written to pages grouped into blocks; erasure operates...
- NAND flash erase block
- The minimum unit that can be electrically erased in NAND flash memory. Erase blocks are larger than write pages (often 256 KB...
- SQLite free page
- A database page that SQLite has placed on an internal free-page list after a row deletion. The page retains its original content...
- Thumbnail cache
- A store of small preview images generated by the OS or applications when media is first viewed. On Android the primary cache...
- TRIM
- A command issued by the file system to the flash controller identifying blocks that are no longer in use, so the controller...
- Wear levelling
- A flash controller algorithm that distributes write operations across all blocks evenly to prevent any single block from wearing out prematurely. A...
Explained in these topics
- Deleted Data Recovery on Mobile DevicesAn Android encryption model introduced in Android 7.0 in which each file is encrypted with a separate key derived from the user credential. FBE replaced full-d...
- Physical Acquisition TechniquesThe encryption model used in modern Android devices (Android 7 and later) and iPhones, in which individual files or directories are encrypted under different k...