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Posted by Jim Michaels on 03/02/06 01:50
<Blackhawk@idonhaceone.com> wrote in message
news:ucqev1hir4m830uk43r17vec3k7a2a0nhf@4ax.com...
> On Sat, 18 Feb 2006 05:29:22 -0000, Jasen Betts <jasen@free.net.nz>
> wrote:
>
>>On 2006-02-17, Blackhawk@idonthaveone.com <Blackhawk@idonthaveone.com>
>>wrote:
>>> I have a guest book and someone is raising hell with me on it. I must
>>> receive 50 entries a day and all bogus. Don't know why they have
>>> picked my site but I have to do something now to correct the on going
>>> problem.
>>>
>>> I need a security feature for my guest book. I have seen some on other
>>> boards where there is a series a letters and or numbers only the human
>>> eye can pick out and enter in order to submit an entry into the guest
>>> book. Can someone direct me to the source of this security script in
>>> php, please!
>>
>>here's one I wrote this afternoon, just to see if it could be done
>>efficently enough in PHP...
>>
>>all the trig (sin()) calls had me worried, but my fears were unfounded
>>trig
>>is much faster on a pentium than it is on an 80386 which was the last time
>>I played with trig-intensive code.
>>
>>when it comes time to validate you may need to map 0 to O and I to 1
>>
>>this code needs the GD library and a TTF font for the text, I used one
>>that
>>was already installed here, but you may need to upload one to your web
>>server.
>>
>>
>><?php // human passgate version 1.0
>>// generate a random text image and store the code in $_SESSION['code']
>>session_start();
>>$iw=500; // width of the text
>>$ih=100; // height of the text
>>$r=30; //distortion radius - final image is this much larger in all
>>directions
>>$f=100; //fraggedness amount of distortion
>>
>>$str=strtoupper(base_convert(rand(1679616,60466176),10,36));
just eliminate the possibility of user confusion.
code fix here:
do {
$str=strtoupper(base_convert(rand(1679616,60466176),10,36));
} while (preg_match("/[OI10]/",$str)); //eliminate user confusion
I had to set the frag to 60 to make it readable. depending on your font and
frag value used, you may also need to eliminate S and 5.
>>$_SESSION['code']=$str;
>>
>>$im = @imagecreate($iw+4*$r,$ih+4*$r)
>> or die("Cannot Initialize new GD image stream");
>>$background_color = imagecolorallocate($im, 0, 0,0);
>>$box_color = imagecolorallocate($im,255,255,255);
>>imagefilledrectangle($im,$r*2,$r*2,$r*2+$iw,$r*2+$ih,$box_color);
>>$tc = imagecolorallocate($im, 233, 14, 91);
>>imagefttext ($im,$ih, 0, 2*$r,$ih+2*$r, $tc,
>> "/var/lib/defoma/gs.d/dirs/fonts/FreeSans.ttf" ,
>> $str );
>>
>>$fr=$f/$r/20000
>>$pxx0=rand(0,360)/180*pi();
>>$pxy0=rand(0,360)/180*pi();
>>$pyx0=rand(0,360)/180*pi();
>>$pyy0=rand(0,360)/180*pi();
>>$fxx=rand(150,200)*$fr;
>>$fxy=rand(150,200)*$fr;
>>$fyx=rand(150,200)*$fr;
>>$fyy=rand(150,200)*$fr;
>>
>>$maxx=$iw+2*$r;
>>$maxy=$ih+2*$r;
>>
>>$img=imagecreate($maxx,$maxy);
>>
>>$pxx=$pxx0;
>>$pxy=$pxy0;
>>
>>$ga = imagecolorallocate($img, 0, 0,0);
>>$go = imagecolorallocate($img,255,255,255);
>>$gf = imagecolorallocate($img, 233, 14, 91);
>>
>>for($x=0;$x<$maxx;$x++)
>>{
>> $pyx=$pyx0;
>> $pyy=$pyy0;
>> $oxx=sin($pxx+=$fxx);
>> $oyy=sin($pxy+=$fxy);
>> for($y=0;$y<$maxy;$y++)
>> {
>> $px=$oxx*sin($pyx+=$fyx)*$r+$r;
>> $py=$oyy*sin($pyy+=$fyy)*$r+$r;
>> $p=imagecolorat($im,$x+$px,$y+$py);
>> imagesetpixel($img,$x,$y,$p);
>> }
>>}
>>header("Content-type: image/png");
>>imagepng($img);
>>imagedestroy($im);
>>imagedestroy($img);
>>?>
>>
>>Bye.
>> Jasen
>
> Jasen,
> Nicely done, would never had thought of this script. What is the GD
> library?
>
> You got me thinking with this information of pre-designed series of
> individual graphic blocks images with alpha and numeric symbols,
> slightly askew and miss shaped. These image blocks can be randomly
> called side by side to form a series of alpha and numeric symbols the
> human would then have to enter on a line to be tested in order to
> submit the entry to the guest book. That would be another way of
> doing what you are doing here but for the simple minded ones like me.
> LOL
>
> I need to try your script but the GD library has me stumped!
>
> Thank you so much for this help.
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