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(U) Al-Hakayimah : The Face that Goes with the Voice
FROM: Adolf Cusmariu
Technical Director, Operational Technologies (S202B11)
Run Date: 08/15/2006
(S//SI) Voice-matching technology is shown to work even when the sound samples come from
different collection sources.
(S) On 5 August 2006, the Qatar-based broadcaster Al-Jazeera relayed yet another audiovisual
message from Al-Qaida's no. 2, Ayman Al-Zawahiri; mathematical voice comparison produced an
excellent match with previous messages.
(S//SI) Noteworthy in this transmission was a bonus: four messages from one Muhammad Khalil
Al-Hakayimah, an Egyptian confirming that a number of members of the Islamic Group in Egypt
has decided to join al-Qa'ida.
(U) video capture of Al-Hakayimah
(S//SI) More detail may be found at:
Al-Zawahiri/Al-Hakayimah video review
...courtesy of
of S202A3. The prospect of matching any available SIGINT with the
"bonus" was realized quickly; the Egyptian -- known as Abu-Jihad al-Misri -- had indeed been a
collection target. Five intercepts containing his confirmed voice (analysis by
of
S2I05) were provided in short order.
(S//SI) Voice matching experiments turned out well; however, one SIGINT intercept had
channel fidelity issues (i.e., clipping) and MIT's algorithm failed; channel mismatch has been a
resilient source of errors in mathematical voice matching. Of course, humans are more adept at
detecting similarities or differences despite degradation. Still, the other four SIGINT voice files
matched the Al-Jazeera transmitted voice exceedingly well.
(S//SI) To ensure robustness, experiments were also performed among the SIGINT intercepts
themselves, involving ten pairings; tests proved the voices were statistically the same. Next,
composite models were built from the SIGINT, including and excluding the clipped intercept.
Once again, the match with open source was excellent.
(S//SI) Bottom line: SIGINT and Open Source audio can yield consistent results in
voice-match tests despite collection differences.
(S) For background info on voice-matching technology, see the article Technology that Identifies
People by the Sound of Their Voice .
"(U//FOUO) SIDtoday articles may not be republished or reposted outside NSANet
without the consent of S0121 (DL sid_comms)."
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DERIVED FROM: NSA/CSSM 1-52, DATED 08 JAN 2007 DECLASSIFY ON: 20320108