TLSH - Technical Papers

## Summary of Papers

- The CTC 2013 paper gives the algorithms for (i) calculating a TLSH hash, and (ii) calculating the distance between two TLSH hashes.
- The ATIS 2014 paper looks at evading TLSH, SSDEEP and SDHASH. This paper looks at the effectiveness of these similarity digests at identifying files when the content of the file is deliberately changed. The paper looks at multiple files types including binary executables, image files, source code and HTML files. For the SSDEEP and SDHASH digest schemes, we were able to evade the scheme in a fairly straight forward way. In particular, we were able to construct very short SED scripts which would break these schemes for source code (1 line SED script) and HTML files (4 line SED script), while maintaining the orginal functionality of the file. TLSH proved a lot harder to break.

  We sent a responsible disclosure to the authors of these schemes before the paper was published.