Initial commit

generate_captcha.sh

@@ -0,0 +1,56 @@
+#!/bin/bash
+
+#
+# Simple script to generate a captcha and rename it with
+# the captcha's value encrypted (AES 128) with a md5 of the AES key.
+# This allow to retrieve captcha's value only with its name
+# if you have the right AES key and also to use a passphrase.
+#
+# The script also contains a visual verification to avoid
+# generating hard to resolve captchas.
+#
+# Parameters :
+# generate_captcha.sh OUT_DIR PASSPHRASE
+#
+
+# Get parameters
+out=$1
+pass=$2
+do_check=1
+
+# Verify parameters
+[ -z "$out" ] && out="."
+[ -z "$pass" ] && pass="AAA"
+[ ! -e $out ] && mkdir $out
+
+# Generate captcha
+res=`./gcaptchaz -f ./scrawl.ttf -o "$out/captcha.png"`
+echo $res | grep "Captcha generated" > /dev/null
+if [ ! $? -eq 0 ] ; then
+    echo $res
+    exit 1
+fi
+
+text=`echo $res | cut -d\" -f2`
+
+# Do verification
+if [ $do_check -eq 1 ] ; then
+    emacs "$out/captcha.png"
+
+    echo -n "Enter CAPTCHA value : "
+    read user
+
+    if [ "$user" != "$text" ] ; then
+	echo "CAPTCHA failed"
+	rm -f "$out/captcha.png"
+	exit 1
+    fi
+
+    echo "CAPTCHA OK"
+fi
+
+# Encrypt captcha's value to generate captcha's name
+key=`echo -n $pass | md5sum | cut -d' ' -f1`
+enc=`echo -n $text | openssl enc -aes-128-ecb -nosalt -K $key -iv $key`
+enc=`echo -n $enc | hexdump -e '"%02x"'`
+mv "$out/captcha.png" "$out/$enc.png"