这是一个自定义加密库。我不太了解PHP的标准函数库，并想知道以下代码是否可以以任何方式得到改进。实现应该产生相同的结果，API应保持原样，但是制作方法更多PHP-ish将非常感激。
代码
<?php
/***************************************
Create random major and minor SPICE key.
***************************************/
function crypt_major()
{
$all = range("\x00", "\xFF");
shuffle($all);
$major_key = implode("", $all);
return $major_key;
}
function crypt_minor()
{
$sample = array();
do
{
array_push($sample, 0, 1, 2, 3);
} while (count($sample) != 256);
shuffle($sample);
$list = array();
for ($index = 0; $index < 64; $index++)
{
$b12 = $sample[$index * 4] << 6;
$b34 = $sample[$index * 4 + 1] << 4;
$b56 = $sample[$index * 4 + 2] << 2;
$b78 = $sample[$index * 4 + 3];
array_push($list, $b12 + $b34 + $b56 + $b78);
}
$minor_key = implode("", array_map("chr", $list));
return $minor_key;
}
/***************************************
Create the SPICE key via the given name.
***************************************/
function named_major($name)
{
srand(crc32($name));
return crypt_major();
}
function named_minor($name)
{
srand(crc32($name));
return crypt_minor();
}
/***************************************
Check validity for major and minor keys.
***************************************/
function _check_major($key)
{
if (is_string($key) && strlen($key) == 256)
{
foreach (range("\x00", "\xFF") as $char)
{
if (substr_count($key, $char) == 0)
{
return FALSE;
}
}
return TRUE;
}
return FALSE;
}
function _check_minor($key)
{
if (is_string($key) && strlen($key) == 64)
{
$indexs = array();
foreach (array_map("ord", str_split($key)) as $byte)
{
foreach (range(6, 0, 2) as $shift)
{
array_push($indexs, ($byte >> $shift) & 3);
}
}
$dict = array_count_values($indexs);
foreach (range(0, 3) as $index)
{
if ($dict[$index] != 64)
{
return FALSE;
}
}
return TRUE;
}
return FALSE;
}
/***************************************
Create encode maps for encode functions.
***************************************/
function _encode_map_1($major)
{
return array_map("ord", str_split($major));
}
function _encode_map_2($minor)
{
$map_2 = array(array(), array(), array(), array());
$list = array();
foreach (array_map("ord", str_split($minor)) as $byte)
{
foreach (range(6, 0, 2) as $shift)
{
array_push($list, ($byte >> $shift) & 3);
}
}
for ($byte = 0; $byte < 256; $byte++)
{
array_push($map_2[$list[$byte]], chr($byte));
}
return $map_2;
}
/***************************************
Create decode maps for decode functions.
***************************************/
function _decode_map_1($minor)
{
$map_1 = array();
foreach (array_map("ord", str_split($minor)) as $byte)
{
foreach (range(6, 0, 2) as $shift)
{
array_push($map_1, ($byte >> $shift) & 3);
}
}
return $map_1;
}function _decode_map_2($major)
{
$map_2 = array();
$temp = array_map("ord", str_split($major));
for ($byte = 0; $byte < 256; $byte++)
{
$map_2[$temp[$byte]] = chr($byte);
}
return $map_2;
}
/***************************************
Encrypt or decrypt the string with maps.
***************************************/
function _encode($string, $map_1, $map_2)
{
$cache = "";
foreach (str_split($string) as $char)
{
$byte = $map_1[ord($char)];
foreach (range(6, 0, 2) as $shift)
{
$cache .= $map_2[($byte >> $shift) & 3][mt_rand(0, 63)];
}
}
return $cache;
}
function _decode($string, $map_1, $map_2)
{
$cache = "";
$temp = str_split($string);
for ($iter = 0; $iter < strlen($string) / 4; $iter++)
{
$b12 = $map_1[ord($temp[$iter * 4])] << 6;
$b34 = $map_1[ord($temp[$iter * 4 + 1])] << 4;
$b56 = $map_1[ord($temp[$iter * 4 + 2])] << 2;
$b78 = $map_1[ord($temp[$iter * 4 + 3])];
$cache .= $map_2[$b12 + $b34 + $b56 + $b78];
}
return $cache;
}
/***************************************
This is the public interface for coding.
***************************************/
function encode_string($string, $major, $minor)
{
if (is_string($string))
{
if (_check_major($major) && _check_minor($minor))
{
$map_1 = _encode_map_1($major);
$map_2 = _encode_map_2($minor);
return _encode($string, $map_1, $map_2);
}
}
return FALSE;
}
function decode_string($string, $major, $minor)
{
if (is_string($string) && strlen($string) % 4 == 0)
{
if (_check_major($major) && _check_minor($minor))
{
$map_1 = _decode_map_1($minor);
$map_2 = _decode_map_2($major);
return _decode($string, $map_1, $map_2);
}
}
return FALSE;
}
?>
这是一个展示如何使用代码的示例。十六进制编辑器可能对输入/输出有帮助。
示例
<?php
# get and process all of the form data
@ $input = htmlspecialchars($_POST["input"]);
@ $majorname = htmlspecialchars($_POST["majorname"]);
@ $minorname = htmlspecialchars($_POST["minorname"]);
@ $majorkey = htmlspecialchars($_POST["majorkey"]);
@ $minorkey = htmlspecialchars($_POST["minorkey"]);
@ $output = htmlspecialchars($_POST["output"]);
# process the submissions by operation
# CREATE
@ $operation = $_POST["operation"];
if ($operation == "Create")
{
if (strlen($_POST["majorname"]) == 0)
{
$majorkey = bin2hex(crypt_major());
}
if (strlen($_POST["minorname"]) == 0)
{
$minorkey = bin2hex(crypt_minor());
}
if (strlen($_POST["majorname"]) != 0)
{
$majorkey = bin2hex(named_major($_POST["majorname"]));
}
if (strlen($_POST["minorname"]) != 0)
{
$minorkey = bin2hex(named_minor($_POST["minorname"]));
}
}
# ENCRYPT or DECRYPT
function is_hex($char)
{
if ($char == "0"):
return TRUE;
elseif ($char == "1"):
return TRUE;
elseif ($char == "2"):
return TRUE;
elseif ($char == "3"):
return TRUE;
elseif ($char == "4"):
return TRUE;
elseif ($char == "5"):
return TRUE;
elseif ($char == "6"):
return TRUE;
elseif ($char == "7"):
return TRUE;
elseif ($char == "8"):
return TRUE;
elseif ($char == "9"):
return TRUE;
elseif ($char == "a"):
return TRUE;
elseif ($char == "b"):
return TRUE;
elseif ($char == "c"):
return TRUE;
elseif ($char == "d"):
return TRUE;
elseif ($char == "e"):
return TRUE;
elseif ($char == "f"):
return TRUE;
else:
return FALSE;
endif;
}
function hex2bin($str)
{
if (strlen($str) % 2 == 0):
$string = strtolower($str);
else:
$string = strtolower("0" . $str);
endif;
$cache = "";
$temp = str_split($str);
for ($index = 0; $index < count($temp) / 2; $index++)
{
$h1 = $temp[$index * 2];
if (is_hex($h1))
{
$h2 = $temp[$index * 2 + 1];
if (is_hex($h2))
{
$cache .= chr(hexdec($h1 . $h2));
}
else
{
return FALSE;
}
}
else
{
return FALSE;
}
}
return $cache;
}
if ($operation == "Encrypt" || $operation == "Decrypt")
{
# CHECK FOR ANY ERROR
$errors = array();
if (strlen($_POST["input"]) == 0)
{
$output = "";
}
$binmajor = hex2bin($_POST["majorkey"]);
if (strlen($_POST["majorkey"]) == 0)
{
array_push($errors, "There must be a major key.");
}
elseif ($binmajor == FALSE)
{
array_push($errors, "The major key must be in hex.");
}
elseif (_check_major($binmajor) == FALSE)
{
array_push($errors, "The major key is corrupt.");
}
$binminor = hex2bin($_POST["minorkey"]);
if (strlen($_POST["minorkey"]) == 0)
{
array_push($errors, "There must be a minor key.");
}
elseif ($binminor == FALSE)
{
array_push($errors, "The minor key must be in hex.");
}
elseif (_check_minor($binminor) == FALSE)
{
array_push($errors, "The minor key is corrupt.");
}
if ($_POST["operation"] == "Decrypt")
{
$bininput = hex2bin(str_replace("\r", "", str_replace("\n", "", $_POST["input"])));
if ($bininput == FALSE)
{
if (strlen($_POST["input"]) != 0)
{
array_push($errors, "The input data must be in hex.");
}
}
elseif (strlen($bininput) % 4 != 0)
{
array_push($errors, "The input data is corrupt.");
}
}
if (count($errors) != 0)
{
# ERRORS ARE FOUND
$output = "ERROR:";
foreach ($errors as $error)
{
$output .= "\n" . $error;
}
}
elseif (strlen($_POST["input"]) != 0)
{
# CONTINUE WORKING
if ($_POST["operation"] == "Encrypt")
{
# ENCRYPT
$output = substr(chunk_split(bin2hex(encode_string($_POST["input"], $binmajor, $binminor)), 58), 0, -2);
}
else
{
# DECRYPT
$output = htmlspecialchars(decode_string($bininput, $binmajor, $binminor));
}
}
}
# echo the form with the values filled
echo "<P><TEXTAREA class=maintextarea name=input rows=25 cols=25>" . $input . "</TEXTAREA></P>\n";
echo "<P>Major Name:</P>\n";
echo "<P><INPUT id=textbox1 name=majorname value=\"" . $majorname . "\"></P>\n";
echo "<P>Minor Name:</P>\n";
echo "<P><INPUT id=textbox1 name=minorname value=\"" . $minorname . "\"></P>\n";
echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Create name=operation>\n";
echo "</DIV>\n";
echo "<P>Major Key:</P>\n";
echo "<P><INPUT id=textbox1 name=majorkey value=\"" . $majorkey . "\"></P>\n";
echo "<P>Minor Key:</P>\n";
echo "<P><INPUT id=textbox1 name=minorkey value=\"" . $minorkey . "\"></P>\n";
echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Encrypt name=operation> \n";
echo "<INPUT class=submit type=submit value=Decrypt name=operation> </DIV>\n";
echo "<P>Result:</P>\n";
echo "<P><TEXTAREA class=maintextarea name=output rows=25 readOnly cols=25>" . $output . "</TEXTAREA></P></DIV></FORM>\n";
?>
应该编辑什么才能提高内存效率或加快执行速度？
答案 0 :(得分：3)
你可以用以下代码替换你的isHex函数：
function isHex($char) {
return strpos("0123456789ABCDEF",strtoupper($char)) > -1;
}
你的hex2bin可能会更好：
function hex2bin($h)
{
if (!is_string($h)) return null;
$r='';
for ($a=0; $a<strlen($h); $a+=2) { $r.=chr(hexdec($h{$a}.$h{($a+1)})); }
return $r;
}
你似乎有很多if..elseif...elseif...elseif在switch中更加清晰，或者分成不同的方法。
但是，我从可维护性和可读性的角度来看更多 - 尽管阅读和理解越容易，但优化起来越容易。如果我通过所有代码并以更清洁的方式编写它会对你有所帮助，那么我会这样做......