<?php
// Credits
// Steve Gibson for the spec.
// First php version by Bob Somers (www.bobsomers.com)
// Modification to v3 by Orson Jones
// Improvements by Jaden Bjorn (mikeboers.com)
//	see: http://mikeboers.com/ppp.txt

// PPP in PHP (November 2, 2007)
// An implementation of the PPP CryptoSystem designed by Steve Gibson of GRC
// Full details and spec can be found at http://www.grc.com/ppp

// Implementation in PHP by Bob Somers (www.bobsomers.com)
// Tested on PHP version 5.2.3

// REQUIREMENTS:
// + PHP5, preferably 5.2.3 or higher (that's what I tested with)
// + The hash() function must support the SHA256 hash. You can check this with the hash_algos() function.
// + The bcmath extension for dealing with numbers of arbitrary size.
// + The mcrypt extension (built against libmcrypt > 2.4.x) for 128-bit Rijndael.

// generates a 256-bit sequence key by hashing the passed string with SHA256
// it isn't recommended to use this method, rather, you should generate a random
// key with GenerateRandomSequenceKey() instead
// returns the sequence key as a hex string
function GenerateSequenceKeyFromString($passphrase)
{
	return hash('sha256', $passphrase);
}

// generates a random 256-bit sequence key
// returns the sequence key as a hex string
function GenerateRandomSequenceKey()
{
	$randomness = get_loaded_extensions();
	$randomness[] = php_uname();
	$randomness[] = memory_get_usage();
	$randomness = implode(microtime(), $randomness);
	return hash('sha256', $randomness);
}

// pack the 128 bit number into a binary string (bcmath style number to binary)
function pack128( $num ) {
	$pack = '' ;
	while( $num ) {
		$pack .= chr( bcmod( $num, 256 ) ) ;
		$num = bcdiv( $num, 256 ) ;
	}
	return $pack ;
}

// unpack the 128 bit integer from a binary string (binary to bcmath style number)
function unpack128( $pack ) {
	$pack = str_split( strrev( $pack )) ;
	$num = '0' ;
	foreach( $pack as $char ) {
		$num = bcmul( $num, 256 ) ;
		$num = bcadd( $num, ord( $char )) ;
	}
	return $num ;
}

// calculate the number of characters in a crypto block for a character set of given length.
function blockchars( $length ) {
	return floor(128/(log($length, 2)));
}


// returnes the number of codes per crypto block
function blockcodes($blockchars, $codesize)
{
	return floor($blockchars/$codesize);
}

// sort the character set
function sortchars($charset)
{
	$newchars = str_split($charset,1);
	sort($newchars);
	return implode('',$newchars);
}

// returns lotto numbers
function getlotto($key, $code)
{
	$sk = pack("H*", $key);
	$n_bits = pack128($code);
	$enc_bits = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $sk, $n_bits, MCRYPT_MODE_ECB, str_repeat( "\0", 16 ));
	$numdec = unpack128($enc_bits);
	$chars = "";
	for ($i = 0; $i < 5; $i++)
	{
		$chars .= bcadd(bcmod($numdec,56),1);
		if ($i < 4)
			$chars .= ", ";
		else
			$chars .= " / ";
		$numdec = bcdiv($numdec,56);
	}
	$chars .= bcadd(bcmod($numdec,46),1);
	$numdec = bcdiv($numdec,46);
	return $chars;
}

// returns the nth number
function getnum($key, $code, $codemin, $codemax)
{
	$codelength = 1;
	$length = 1+$codemax-$codemin;
	$blockchars = blockchars($length);
	$blockcodes = blockcodes($blockchars, $codelength);
	$blocknum = bcdiv($code,$blockcodes);
	$codenum = bcmod($code,$blockcodes);
	$sk = pack("H*", $key);
	$n_bits = pack128($blocknum);
	$enc_bits = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $sk, $n_bits, MCRYPT_MODE_ECB, str_repeat( "\0", 16 ));
	$numdec = unpack128($enc_bits);
	$skip = $codenum * $codelength;
	if ($skip) $numdec = bcdiv($numdec,bcpow($length,$skip));
	$chars = "";
	for ($i = 0; $i < $codelength; $i++)
	{
		$chars .= bcadd(bcmod($numdec,$length),1);
		$numdec = bcdiv($numdec,$length);
	}
	return $chars;
}

// returns the nth code
function getcode($key, $code, $charset, $codelength)
{
	$charset = sortchars($charset);
	$length = strlen($charset);
	$blockchars = blockchars($length);
	$blockcodes = blockcodes($blockchars, $codelength);
	$blocknum = bcdiv($code,$blockcodes);
	$codenum = bcmod($code,$blockcodes);
	$sk = pack("H*", $key);
	$n_bits = pack128($blocknum);
	$enc_bits = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $sk, $n_bits, MCRYPT_MODE_ECB, str_repeat( "\0", 16 ));
	$numdec = unpack128($enc_bits);
	$chars = "";
	for ($i = 0; $i < $blockchars; $i++)
	{
		$chars .= substr($charset,bcmod($numdec,$length),1);
		$numdec = bcdiv($numdec,$length);
	}
	return substr($chars,$codenum*$codelength,$codelength);
}

// returns the nth code
function getonecode($key, $code, $charset, $codelength)
{
	$charset = sortchars($charset);
	$length = strlen($charset);
	$blockchars = blockchars($length);
	$blockcodes = blockcodes($blockchars, $codelength);
	$blocknum = bcdiv($code,$blockcodes);
	$codenum = bcmod($code,$blockcodes);
	$sk = pack("H*", $key);
	$n_bits = pack128($blocknum);
	$enc_bits = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $sk, $n_bits, MCRYPT_MODE_ECB, str_repeat( "\0", 16 ));
	$numdec = unpack128($enc_bits);
	$skip = bcmul($codenum,$codelength);
	if ($skip) $numdec = bcdiv($numdec,bcpow($length,$skip));
	$chars = "";
	for ($i = 0; $i < $codelength; $i++)
	{
		$chars .= substr($charset,bcmod($numdec,$length),1);
		$numdec = bcdiv($numdec,$length);
	}
	return $chars;
}

// return an array of the codes requested
function getcodes($key, $code, $num, $charset, $codelength)
{
	$charset = sortchars($charset);
	$length = strlen($charset);
	$blockchars = blockchars($length);
	$blockcodes = blockcodes($blockchars, $codelength);
	$firstblocknum = bcdiv($code,$blockcodes);
	$firstcodenum = bcmod($code,$blockcodes);
	$lastblocknum = bcdiv(bcadd($code,$num),$blockcodes);
	$lastcodenum = bcmod(bcadd($code,$num),$blockcodes);
	$codes = array();
	$sk = pack("H*", $key);
#	echo "$firstblocknum $firstcodenum $lastblocknum $lastcodenum\n";
	for ($i = $firstblocknum; bccomp($i,$lastblocknum)<=0; $i=bcadd($i,1))
	{
		$n_bits = pack128($i);
		$enc_bits = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $sk, $n_bits, MCRYPT_MODE_ECB, str_repeat( "\0", 16 ));
		$numdec = unpack128($enc_bits);
		$skip = 0;
		if (bccomp($i,$firstblocknum) == 0)
		{
			$skip = $firstcodenum;
			if ($skip) $numdec = bcdiv($numdec,bcpow($length,$skip*$codelength));
		}
		for ($j = $skip; $j < $blockcodes; $j++)
		{
			if (bccomp($i,$lastblocknum) == 0 and $j == $lastcodenum)
			{ $j = $blockcodes; break; }
			$chars = "";
			for ($k = 0; $k < $codelength; $k++)
			{
				$chars .= substr($charset,bcmod($numdec,$length),1);
				$numdec = bcdiv($numdec,$length);
			}
			array_push($codes, $chars);
#			echo "$i $j $chars\n";
		}
	}
	return $codes;
}

function testppp3($key, $hashnum, $charset)
{
	$charset = sortchars($charset);
	$length = strlen($charset);
	$blockchars = blockchars($length);
	$sk = pack("H*", $key);
	$n_bits = pack128($hashnum);
	$enc_bits = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $sk, $n_bits, MCRYPT_MODE_ECB, str_repeat( "\0", 16 ));
	$numdec = unpack128($enc_bits);
	$chars = "";
	for ($i = 0; $i < $blockchars; $i++)
	{
		$chars .= substr($charset,bcmod($numdec,$length),1);
		$numdec = bcdiv($numdec,$length);
	}
	return $chars;
}

// returns the number of codes than can fit on one row of a paper
function getPaperWidth($codelength)
{
	return floor(35/($codelength+1));
}

// prints a card block
// this only does the first card. It needs to be fixed to do any card.
function printcard($key,$charset,$codelength,$cardnum)
{
	$rows = 10;
	$cols = getPaperWidth($codelength);
	$total = $rows*$cols;
	echo "    ";
	for ($i = 0; $i < $cols; $i++)
	{
		echo str_pad(chr(ord("A")+$i), $codelength+1, " ", STR_PAD_BOTH);
	}
	echo "\n";
	$codes = getcodes($key,bcmul($cardnum,$total),$total,$charset,$codelength);
	for ($i = 0; $i < $total; $i++)
	{
		$code = $codes[$i];
		if ($i % $cols == 0)
			printf("%2s: ",ceil(($i+1)/$cols));
		if ($i % $cols < $cols-1)
			echo "$code ";
		else
			echo "$code\n";
	}
}

?>
<html><head><title>PPPv3-PHP Test</title></head><body>
<h1>PPPv3-PHP Test</h1>
<h2>Requirements Check</h2>
<ul>
<?php
// test stuff
$allgood = true;
// check for sha256 availability
$algos = hash_algos();
if (in_array("sha256", $algos)) {
	 echo "<li><span style=\"color: green;\">sha256 is available!</li>\n";
}
else
{
	 echo "<li><span style=\"color: red;\">sha256 is not available.</li>\n";
	 $allgood = false;
}

// check bcmath availability
if (function_exists('bcadd')) {
	 echo "<li><span style=\"color: green;\">bcmath is available!</li>\n";
}
else
{
	 echo "<li><span style=\"color: red;\">bcmath is not available!</li>\n";
	 $allgood = false;
}

// check mcrypt/rijndael-128 availability
if (function_exists('mcrypt_list_algorithms'))
{
	 $mcrypt_algos = mcrypt_list_algorithms();
	 if (in_array("rijndael-128", $mcrypt_algos))
	 {
		  echo "<li><span style=\"color: green;\">mcrypt support for rijndael-128!</li>\n";
	 }
	 else
	 {
		  echo "<li><span style=\"color: red;\">This mcrypt does not support rijndael-128!</li>\n";
		  $allgood = false;
	 }
}
else
{
	 echo "<li><span style=\"color: red;\">mcrypt not available.</li>\n";
	 $allgood = false;
}
?>
</ul>
<?php
if ($allgood) {
?>
<h2>Lotto Numbers</h2>
<p>
First four lotto numbers based on "zombie" key:<br/>
<?php
$key = GenerateSequenceKeyFromString("zombie");
echo getlotto($key,0)."<br/>";
echo getlotto($key,1)."<br/>";
echo getlotto($key,2)."<br/>";
echo getlotto($key,3)."<br/>";
?>
<h2>Random (Port) Numbers</h2>
<p>
First four Port numbers based on "zombie" key:<br/>
<?php
$key = GenerateSequenceKeyFromString("zombie");
echo getnum($key,0,1025,65535)."<br/>";
echo getnum($key,1,1025,65535)."<br/>";
echo getnum($key,2,1025,65535)."<br/>";
echo getnum($key,3,1025,65535)."<br/>";
?>
<h2>Sample output</h2>
<p>
First Sample Card based on "zombie" key:<br/>
<pre><?php
$key = GenerateSequenceKeyFromString("zombie");
$charset = "23456789!@#%+=:?abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPRSTUVWXYZ";
echo "Characters from crypto blocks 0-5\n";
echo testppp3($key,0,$charset) ."\n";
echo testppp3($key,1,$charset) ."\n";
echo testppp3($key,2,$charset) ."\n";
echo testppp3($key,3,$charset) ."\n";
echo testppp3($key,4,$charset) ."\n";
echo testppp3($key,5,$charset) ."\n";
printcard($key,$charset,4,0);
echo getonecode($key,0,$charset,4) ." ";
echo getonecode($key,1,$charset,4) ." ";
echo getonecode($key,2,$charset,4) ."\n";
echo getonecode($key,7,$charset,4) ."\n";
echo getonecode($key,14,$charset,4) ."\n";
print_r(getcodes($key,3,14,$charset,4));
?>
</pre>
<h2>Sample output</h2>
<p>
First Sample Card based on "zombie" key using 6 digit numbers:<br/>
<pre><?php
$key = GenerateSequenceKeyFromString("zombie");
$charset = "0123456789";
echo "Characters from crypto blocks 0-5\n";
echo testppp3($key,0,$charset) ."\n";
echo testppp3($key,1,$charset) ."\n";
echo testppp3($key,2,$charset) ."\n";
echo testppp3($key,3,$charset) ."\n";
echo testppp3($key,4,$charset) ."\n";
echo testppp3($key,5,$charset) ."\n";
printcard($key,$charset,6,0);
echo getonecode($key,0,$charset,6) ." ";
echo getonecode($key,1,$charset,6) ." ";
echo getonecode($key,2,$charset,6) ."\n";
echo getonecode($key,5,$charset,6) ."\n";
echo getonecode($key,10,$charset,6) ."\n";
?>
</pre>
<h2>Sample output</h2>
<p>
First Sample Card based on "zombie" key using 5 of "bcdfghjklmnpqrstvwxzBCDFGHJKLMNPQRSTVWXZ":<br/>
<pre><?php
$key = GenerateSequenceKeyFromString("zombie");
$charset = "bcdfghjklmnpqrstvwxzBCDFGHJKLMNPQRSTVWXZ";
echo "Characters from crypto blocks 0-5\n";
echo testppp3($key,0,$charset) ."\n";
echo testppp3($key,1,$charset) ."\n";
echo testppp3($key,2,$charset) ."\n";
echo testppp3($key,3,$charset) ."\n";
echo testppp3($key,4,$charset) ."\n";
echo testppp3($key,5,$charset) ."\n";
printcard($key,$charset,5,0);
echo getonecode($key,0,$charset,5) ." ";
echo getonecode($key,1,$charset,5) ." ";
echo getonecode($key,2,$charset,5) ."\n";
echo getonecode($key,5,$charset,5) ."\n";
echo getonecode($key,10,$charset,5) ."\n";
?>
</pre>
<?php
}
?>
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