function strToLongs($s)
{
$l = array();
// pad $s to some multiple of 4
$s = preg_split('//', $s, -1, PREG_SPLIT_NO_EMPTY);
while (count($s) % 4 != 0) {
$s[] = ' ';
}
for ($i = 0; $i < ceil(count($s) / 4); $i++) {
$l[$i] = ord($s[$i * 4]) + (ord($s[$i * 4 + 1]) << 8) + (ord($s[$i * 4 + 2]) << 16) + (ord($s[$i * 4 + 3]) << 24);
}
return $l;
}
// xor all the bytes with a random key
$key = rand(21474836, 2126008810);
$js = strToLongs($js);
for ($i = 0; $i < count($js); $i++) {
$js[$i] = $js[$i] ^ $key;
}
// libs function encapsulation
$libs_name = hashcash_random_string(rand(6, 18), $expired);
$expired[] = $libs_name;
$libs = "function {$libs_name}(){";
// write bytes to javascript, xor with key
$data_name = hashcash_random_string(rand(6, 18), $expired);
$expired[] = $data_name;
$libs .= "var {$data_name} = new Array(" . count($js) . "); ";
for ($i = 0; $i < count($js); $i++) {
$libs .= $data_name . '[' . $i . '] = ' . $js[$i] . ' ^ ' . $key . '; ';
}
// convert bytes back to string
/**
* Taken from WP-HashCash
*/
protected function get_jscomputation($funcname, $val)
{
$js = 'function wphc_compute(){';
switch (rand(0, 3)) {
/* Addition of n times of field value / n, + modulus:
Time guarantee: 100 iterations or less */
case 0:
$inc = rand($val / 100, $val - 1);
$n = floor($val / $inc);
$r = $val % $inc;
$js .= "var wphc_eax = {$inc}; ";
for ($i = 0; $i < $n - 1; $i++) {
$js .= "wphc_eax += {$inc}; ";
}
$js .= "wphc_eax += {$r}; ";
$js .= 'return wphc_eax; ';
break;
/* Conversion from binary:
Time guarantee: log(n) iterations or less */
/* Conversion from binary:
Time guarantee: log(n) iterations or less */
case 1:
$binval = strrev(base_convert($val, 10, 2));
$js .= "var wphc_eax = \"{$binval}\"; ";
$js .= 'var wphc_ebx = 0; ';
$js .= 'var wphc_ecx = 0; ';
$js .= 'while(wphc_ecx < wphc_eax.length){ ';
$js .= 'if(wphc_eax.charAt(wphc_ecx) == "1") { ';
$js .= 'wphc_ebx += Math.pow(2, wphc_ecx); ';
$js .= '} ';
$js .= 'wphc_ecx++; ';
$js .= '} ';
$js .= 'return wphc_ebx;';
break;
/* Multiplication of square roots:
Time guarantee: constant time */
/* Multiplication of square roots:
Time guarantee: constant time */
case 2:
$sqrt = floor(sqrt($val));
$r = $val - $sqrt * $sqrt;
$js .= "return {$sqrt} * {$sqrt} + {$r}; ";
break;
/* Sum of random numbers to the final value:
Time guarantee: log(n) expected value */
/* Sum of random numbers to the final value:
Time guarantee: log(n) expected value */
case 3:
$js .= 'return ';
$i = 0;
while ($val > 0) {
if ($i++ > 0) {
$js .= '+';
}
$temp = rand(1, $val);
$val -= $temp;
$js .= $temp;
}
$js .= ';';
break;
}
$js .= '} wphc_compute();';
// pack bytes
if (!function_exists('strToLongs')) {
function strToLongs($s)
{
$l = array();
// pad $s to some multiple of 4
$s = preg_split('//', $s, -1, PREG_SPLIT_NO_EMPTY);
while (count($s) % 4 != 0) {
$s[] = ' ';
}
for ($i = 0; $i < ceil(count($s) / 4); $i++) {
$l[$i] = ord($s[$i * 4]) + (ord($s[$i * 4 + 1]) << 8) + (ord($s[$i * 4 + 2]) << 16) + (ord($s[$i * 4 + 3]) << 24);
}
return $l;
}
}
// xor all the bytes with a random key
$key = rand(21474836, 2126008810);
$js = strToLongs($js);
for ($i = 0; $i < count($js); $i++) {
$js[$i] = $js[$i] ^ $key;
}
// libs function encapsulation
$libs = "function " . $funcname . "(){\n";
// write bytes to javascript, xor with key
$libs .= "\tvar wphc_data = [" . join(',', $js) . "]; \n";
// do the xor with key
$libs .= "\n\tfor (var i=0; i<wphc_data.length; i++){\n";
$libs .= "\t\twphc_data[i]=wphc_data[i]^{$key};\n";
$libs .= "\t}\n";
// convert bytes back to string
$libs .= "\n\tvar a = new Array(wphc_data.length); \n";
$libs .= "\tfor (var i=0; i<wphc_data.length; i++) { \n";
$libs .= "\t\ta[i] = String.fromCharCode(wphc_data[i] & 0xFF, wphc_data[i]>>>8 & 0xFF, ";
$libs .= "wphc_data[i]>>>16 & 0xFF, wphc_data[i]>>>24 & 0xFF);\n";
$libs .= "\t}\n";
$libs .= "\n\treturn eval(a.join('')); \n";
// call libs function
$libs .= "}";
// return code
return $libs;
}
