\subsection{Audio}

\subsubsection{Privacy}
Excellent\\
Audio CAPTCHA doesn't employ any tracking elements and works when used in anonymous
networks like TOR\@.

\subsubsection{Effectiveness}
Bad\\

There are browser extensions available to bypass audio CAPTCHAs.

% TODO cite CAPTCHA farm cost analysis paper
ease.
\subsubsection{Accessibility}
Bad\\

Audio CAPTCHAs are inaccessible to non-English speaking users and users with
auditory disabilities.

\subsubsection{Accuracy}
Bad\\

Success and failure are absolute states in this method. A solution that doesn't
match the audio content results in failure while a match is considered a
success. But when above-mentioned circumvention methods are used, there will be
results will be completely inaccurate and as the system lacks any adaptational
capabilities, the failure will be long-lasting.  

The method uses only challenge solutions in its decision process. No other
external factors are involved.