RCMP TSSIT OPS-II is a software based data sanitization method used in various file shredder and data destruction programs to overwrite existing information on a hard drive or other storage device. Erasing a hard drive using the RCMP TSSIT OPS-II data sanitization method will prevent all software based file recovery methods from finding information on the drive and is also likely to prevent most hardware based recovery methods from extracting information.

What Does RCMP TSSIT OPS-II Do?
Some data sanitization methods will overwrite all the data with just zeros, like Write Zero. Others may use ones as well like Secure Erase, while some data wipe methods use random characters like with the Random Data and Gutmann methods. RCMP TSSIT OPS-II combines these methods and is usually implemented in the following way:

Pass 1: Writes a zero
Pass 2: Writes one
Pass 3: Writes a zero
Pass 4: Writes one
Pass 5: Writes a zero
Pass 6: Writes one
Pass 7: Writes a random character and verifies the write

The RCMP TSSIT OPS-II data sanitization method is usually correctly used as we show above, but we've also seen it implemented with random characters in place of some of the zero/one repeating passes in some programs. What's meant by verifying the write in Pass 7 is just that the software that's using the data sanitization method will check that the storage device has actually been overwritten with random characters - the DoD 5220.22-M method does this after every single one of its passes. A verify pass will normally repeat itself if the verification check fails.

Tip: Many programs that support the RCMP TSSIT OPS-II wipe method will let you run the above sequence multiple times. That means after writing all the ones and zeros and then finishing with random characters, the application will just start back over from the beginning and continue to do that for however many repeats you've selected.

More About RCMP TSSIT OPS-II
The RCMP TSSIT OPS-II sanitization method was originally defined in Appendix Ops-II: Media Sanitization of the Technical Security Standards for Information Technology document, published by the Royal Canadian Mounted Police (RCMP). It's available here as a PDF.

However, RCMP TSSIT OPS-II is no longer the Canadian government's software-based data sanitization standard. The data sanitization standard in Canada is now CSEC ITSG-06 or a program that utilizes Secure Erase.