验证码加密

我创建了一个验证码图像制作程序与PHP验证码加密

<?php 
function word($n) { 
    $consonants = "bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ"; 
    $vowels = "aeiou"; 
    $word[1] = $consonants[rand(0, 41)]; 
    $word[2] .= $vowels[rand(0, 4)]; 
    $word[3] .= $consonants[rand(0, 41)]; 
    $word[4] .= $consonants[rand(0, 41)]; 
    return $word[$n]; 
} 

    $xs = 550; 
    $ys = 300; 
    $im = imagecreatetruecolor($xs, $ys); 
    $newim = imagecreatetruecolor($xs, $ys); 
    imagettftext($im, $ys/5, rand(-10, 10), rand(0, 10), $ys/2, 0xFFFFFF, "geosans.ttf", word(1)); 
    imagettftext($im, $ys/4.5, rand(-10, 10), rand(50, 70), $ys/2, 0xFFFFFF, "geosans.ttf", word(2)); 
    imagettftext($im, $ys/4, rand(-10, 10), rand(100, 150), $ys/2, 0xFFFFFF, "geosans.ttf", word(3)); 
    imagettftext($im, $ys/3.5, rand(-10, 10), rand(185, 210), $ys/2, 0xFFFFFF, "geosans.ttf", word(4)); 
    for ($x=0; $x<=$xs;$x++){ 
     for ($y=0; $y<=$ys;$y++){ 
      $rgba = imagecolorsforindex($im, imagecolorat($im, $x, $y)); 
      $col = imagecolorallocate($newim, $rgba["red"], $rgba["green"], $rgba["blue"]); 

      $distorted_y = ($y + round(45*sin($x/50)) + imagesy($im)) % imagesy($im); 
      imagesetpixel($newim, $x, $distorted_y, $col); 
     } 
    } 

    imagefilter($newim, IMG_FILTER_NEGATE); 


    header("Content-type: image/png"); 
    imagepng($newim); 
?>

但我怎么能申请吗？

怎样的官方验证码网站加密他们的真实

这是一个例子

http://www.google.com/recaptcha/api/image?c=03AHJ_VutAc1sMxyCE0N98Kh2AfMGlGmu7_DzzFP3Rn1gLHdbDulOQYK0w-sVrxqHWSTBCfVBipmqY-ywmme2_cuClW5QBRzKdzRSJeMWyme1aoGZ-y0OluiSfn-uKDExfVCo2PGrTao2wWpBLultbUEsctlJ97JXKCQ

总的来说，我问我怎么能放心地加密数据？

来源

2010-09-11 Mark Lalor