Does Secure Empty Trash work on Mac w SSD?

Question

Given that an SSD does wear leveling, does the Secure Empty Trash on the menu in MacOSX really work? Is something special being done force overwrites to the same physical block of flash and bypass the wear leveling algorithms built into the SSD?

(related QA on SO)

Answer 1

SSD wear levelling poses a prickly problem for secure deletion. Wear levelling is a low level algorithm working in the drive that randomises where data is written. This happens independent of the OS.

By design, wear levelling spreads out multiple writes to the same file across a flash drive. This keeps a file (like a log or page file) from wearing out a specific part of the memory. This keeps your SSD from failing prematurely, but it also makes it almost impossible to overwrite a specific block of memory.

Your best bet, if the data is that important, is to use a block or file level encryption (like TrueCrypt).