From 2b342d2de479c3204e8fb8114a2798c1403e7c17 Mon Sep 17 00:00:00 2001
From: realaravinth <realaravinth@batsense.net>
Date: Mon, 20 Sep 2021 17:15:45 +0530
Subject: [PATCH] add prerequisite section and captcha farms info

---
 analysis/align-obj.tex    |  5 ++++-
 paper.tex                 |  1 +
 pre-req/captcha-farms.tex | 12 ++++++++++++
 pre-req/main.tex          |  3 +++
 4 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 pre-req/captcha-farms.tex
 create mode 100644 pre-req/main.tex

diff --git a/analysis/align-obj.tex b/analysis/align-obj.tex
index d4da973..2d4206b 100644
--- a/analysis/align-obj.tex
+++ b/analysis/align-obj.tex
@@ -8,7 +8,10 @@ Good\\
 The method relies on Optical Character Recognition (OCR) capabilities of human
 users. OCR technology is becoming increasingly sophisticated which would render
 this method ineffective in the future.
-Object  Recognition Technology is becoming
+
+Without OCR, this method can be bypassed using human-powered CAPTCHA farms with
+% TODO cite CAPTCHA farm cost analysis paper
+ease. On an average, farms generate one CAPTCHA solution every 40 seconds
 \subsubsection{Accessibility}
 \subsubsection{Accuracy}
 \subsubsection{Privacy}
diff --git a/paper.tex b/paper.tex
index c2510ab..65f79d7 100644
--- a/paper.tex
+++ b/paper.tex
@@ -10,6 +10,7 @@
 \maketitle
 
 \input{intro/intro.tex}
+\input{pre-req/main.tex}
 \input{analysis/main.tex}
 
 \end{document}
diff --git a/pre-req/captcha-farms.tex b/pre-req/captcha-farms.tex
new file mode 100644
index 0000000..21c0334
--- /dev/null
+++ b/pre-req/captcha-farms.tex
@@ -0,0 +1,12 @@
+\subsection{CAPTCHA farms}
+CAPTCHA farms are run using cheap labor available in third-world countries. When
+an attacker seeks the services of a CAPTCHA farm, they are provided access to an
+web API to forward CAPTCHA challenges. A labourer working in the farm solves the
+CAPTCHA and the API responds with the solution. The whole process takes less
+then a minute to complete and costs only a fraction of what premium services
+like reCAPTCHA charge.
+
+Overall, this attack is very feasible and cheap and is frequently used to bypass
+traditional CAPTCHA systems.
+
+%% TODO insert price charts
diff --git a/pre-req/main.tex b/pre-req/main.tex
new file mode 100644
index 0000000..23d6472
--- /dev/null
+++ b/pre-req/main.tex
@@ -0,0 +1,3 @@
+\section{Prerequisite}
+
+\input{pre-req/captcha-farms.tex}