PHP中的MD5实现 - 我哪里出错了？

Question

我知道这可能是一个漫长的过程,但有人可能会告诉我在PHP中当前实现的MD5算法出错了吗？我似乎无法弄清楚它有什么问题.

它返回一个32个字符的十六进制字符串(25%的时间它产生的字符串少于32个字符),但它没有产生与内置MD5函数相同的32个字符.

非常感谢你.

---

<?php

function MD($string){
$a = "67452301";
$b = "EFCDAB89";
$c = "98BADCFE";
$d = "10325476";

$words = init($string);

for($i = 0; $i <= count($words)/16-1; $i++){
    $A = $a;
    $B = $b;
    $C = $c;
    $D = $d;

    /* ROUND 1 */
    FF ($A, $B, $C, $D, $words[0 + ($i * 16)], 7, "d76aa478"); 
    FF ($D, $A, $B, $C, $words[1 + ($i * 16)], 12, "e8c7b756"); 
    FF ($C, $D, $A, $B, $words[2 + ($i * 16)], 17, "242070db"); 
    FF ($B, $C, $D, $A, $words[3 + ($i * 16)], 22, "c1bdceee"); 
    FF ($A, $B, $C, $D, $words[4 + ($i * 16)], 7, "f57c0faf"); 
    FF ($D, $A, $B, $C, $words[5 + ($i * 16)], 12, "4787c62a"); 
    FF ($C, $D, $A, $B, $words[6 + ($i * 16)], 17, "a8304613"); 
    FF ($B, $C, $D, $A, $words[7 + ($i * 16)], 22, "fd469501"); 
    FF ($A, $B, $C, $D, $words[8 + ($i * 16)], 7, "698098d8"); 
    FF ($D, $A, $B, $C, $words[9 + ($i * 16)], 12, "8b44f7af"); 
    FF ($C, $D, $A, $B, $words[10 + ($i * 16)], 17, "ffff5bb1"); 
    FF ($B, $C, $D, $A, $words[11 + ($i * 16)], 22, "895cd7be"); 
    FF ($A, $B, $C, $D, $words[12 + ($i * 16)], 7, "6b901122"); 
    FF ($D, $A, $B, $C, $words[13 + ($i * 16)], 12, "fd987193"); 
    FF ($C, $D, $A, $B, $words[14 + ($i * 16)], 17, "a679438e"); 
    FF ($B, $C, $D, $A, $words[15 + ($i * 16)], 22, "49b40821"); 

    /* ROUND 2 */
    GG ($A, $B, $C, $D, $words[1 + ($i * 16)], 5, "f61e2562"); 
    GG ($D, $A, $B, $C, $words[6 + ($i * 16)], 9, "c040b340"); 
    GG ($C, $D, $A, $B, $words[11 + ($i * 16)], 14, "265e5a51"); 
    GG ($B, $C, $D, $A, $words[0 + ($i * 16)], 20, "e9b6c7aa"); 
    GG ($A, $B, $C, $D, $words[5 + ($i * 16)], 5, "d62f105d"); 
    GG ($D, $A, $B, $C, $words[10 + ($i * 16)], 9, "02441453"); 
    GG ($C, $D, $A, $B, $words[15 + ($i * 16)], 14, "d8a1e681"); 
    GG ($B, $C, $D, $A, $words[4 + ($i * 16)], 20, "e7d3fbc8"); 
    GG ($A, $B, $C, $D, $words[9 + ($i * 16)], 5, "21e1cde6"); 
    GG ($D, $A, $B, $C, $words[14 + ($i * 16)], 9, "c33707d6"); 
    GG ($C, $D, $A, $B, $words[3 + ($i * 16)], 14, "f4d50d87"); 
    GG ($B, $C, $D, $A, $words[8 + ($i * 16)], 20, "455a14ed"); 
    GG ($A, $B, $C, $D, $words[13 + ($i * 16)], 5, "a9e3e905"); 
    GG ($D, $A, $B, $C, $words[2 + ($i * 16)], 9, "fcefa3f8"); 
    GG ($C, $D, $A, $B, $words[7 + ($i * 16)], 14, "676f02d9"); 
    GG ($B, $C, $D, $A, $words[12 + ($i * 16)], 20, "8d2a4c8a"); 

    /* ROUND 3 */
    HH ($A, $B, $C, $D, $words[5 + ($i * 16)], 4, "fffa3942"); 
    HH ($D, $A, $B, $C, $words[8 + ($i * 16)], 11, "8771f681"); 
    HH ($C, $D, $A, $B, $words[11 + ($i * 16)], 16, "6d9d6122"); 
    HH ($B, $C, $D, $A, $words[14 + ($i * 16)], 23, "fde5380c"); 
    HH ($A, $B, $C, $D, $words[1 + ($i * 16)], 4, "a4beea44"); 
    HH ($D, $A, $B, $C, $words[4 + ($i * 16)], 11, "4bdecfa9"); 
    HH ($C, $D, $A, $B, $words[7 + ($i * 16)], 16, "f6bb4b60"); 
    HH ($B, $C, $D, $A, $words[10 + ($i * 16)], 23, "bebfbc70"); 
    HH ($A, $B, $C, $D, $words[13 + ($i * 16)], 4, "289b7ec6"); 
    HH ($D, $A, $B, $C, $words[0 + ($i * 16)], 11, "eaa127fa"); 
    HH ($C, $D, $A, $B, $words[3 + ($i * 16)], 16, "d4ef3085"); 
    HH ($B, $C, $D, $A, $words[6 + ($i * 16)], 23, "04881d05"); 
    HH ($A, $B, $C, $D, $words[9 + ($i * 16)], 4, "d9d4d039"); 
    HH ($D, $A, $B, $C, $words[12 + ($i * 16)], 11, "e6db99e5"); 
    HH ($C, $D, $A, $B, $words[15 + ($i * 16)], 16, "1fa27cf8"); 
    HH ($B, $C, $D, $A, $words[2 + ($i * 16)], 23, "c4ac5665"); 

    /* ROUND 4 */
    II ($A, $B, $C, $D, $words[0 + ($i * 16)], 6, "f4292244"); 
    II ($D, $A, $B, $C, $words[7 + ($i * 16)], 10, "432aff97"); 
    II ($C, $D, $A, $B, $words[14 + ($i * 16)], 15, "ab9423a7"); 
    II ($B, $C, $D, $A, $words[5 + ($i * 16)], 21, "fc93a039"); 
    II ($A, $B, $C, $D, $words[12 + ($i * 16)], 6, "655b59c3"); 
    II ($D, $A, $B, $C, $words[3 + ($i * 16)], 10, "8f0ccc92"); 
    II ($C, $D, $A, $B, $words[10 + ($i * 16)], 15, "ffeff47d"); 
    II ($B, $C, $D, $A, $words[1 + ($i * 16)], 21, "85845dd1"); 
    II ($A, $B, $C, $D, $words[8 + ($i * 16)], 6, "6fa87e4f"); 
    II ($D, $A, $B, $C, $words[15 + ($i * 16)], 10, "fe2ce6e0"); 
    II ($C, $D, $A, $B, $words[6 + ($i * 16)], 15, "a3014314"); 
    II ($B, $C, $D, $A, $words[13 + ($i * 16)], 21, "4e0811a1"); 
    II ($A, $B, $C, $D, $words[4 + ($i * 16)], 6, "f7537e82"); 
    II ($D, $A, $B, $C, $words[11 + ($i * 16)], 10, "bd3af235"); 
    II ($C, $D, $A, $B, $words[2 + ($i * 16)], 15, "2ad7d2bb"); 
    II ($B, $C, $D, $A, $words[9 + ($i * 16)], 21, "eb86d391"); 

    addVars($a, $b, $c, $d, $A, $B, $C, $D);    
}
    $MD5 = $a.$b.$c.$d;
    return $MD5;
}

/* General functions */

function hexbin($str){
    $hexbinmap = array("0" => "0000"
                     , "1" => "0001"
                     , "2" => "0010"
                     , "3" => "0011"
                     , "4" => "0100"
                     , "5" => "0101"
                     , "6" => "0110"
                     , "7" => "0111"
                     , "8" => "1000"
                     , "9" => "1001"
                     , "A" => "1010"
                     , "a" => "1010"
                     , "B" => "1011"
                     , "b" => "1011"
                     , "C" => "1100"
                     , "c" => "1100"
                     , "D" => "1101"
                     , "d" => "1101"
                     , "E" => "1110"
                     , "e" => "1110"
                     , "F" => "1111"
                     , "f" => "1111");                    
    $bin = "";
    for ($i = 0; $i < strlen($str); $i++)
    {
        $bin .= $hexbinmap[$str[$i]];
    }
    $bin = ltrim($bin, '0'); 
    // echo "Original: ".$str."  New: ".$bin."<br />";
    return $bin;
}

function strhex($str){
    $hex = "";
    for ($i = 0; $i < strlen($str); $i++)
    {
        $hex = $hex.dechex(ord($str[$i]));
    }
    return $hex;
}


/* MD5-specific functions */

function init($string){
    $len = strlen($string);
    $hex = strhex($string); // convert ascii string to hex
    $bin = hexbin($hex); // convert hex string to bin
    $padded = pad($bin);
    $padded = pad($padded, 1, $len);
    $block = str_split($padded, 32);
    return $block;
}

function pad($bin, $type=0, $len = 0){
    if($type == 0){
        $bin = $bin."1";
        $buff = strlen($bin) % 512;
        if($buff != 448){
            while(strlen($bin) % 512 != 448){
                $bin = $bin."0";
            }
        }
    }
    // append length (b) of string to latter 64 bits
    elseif($type == 1){
        $bLen = decbin($len);
        if(strlen($bLen) > 64){
            $words = truncate64($bLen);
            $bin .= $words[1].$words[0];
        }
        else{
            while(strlen($bLen) < 64){
                $bLen .= "0";
            }
            $words = str_split ($bLen, 32);
            $bin .= $words[1].$words[0];
        }

    }
    return $bin;
}

function truncate64($string){
    $trunc = substr($string, strlen($string) - 64, 64);
    $trunc = str_split ($trunc, 32);
    return $trunc;
}


/* MD5 base functions */

function F($X, $Y, $Z){
    $X = hexbin($X);
    $Y = hexbin($Y);
    $Z = hexbin($Z);
    $calc = ($X & $Y) | ((~ $X) & $Z); // X AND Y OR NOT X AND Z
    $calc = bindec($calc);
    return  $calc; 
}

function G($X, $Y, $Z){
    $X = hexbin($X);
    $Y = hexbin($Y);
    $Z = hexbin($Z);
    $calc = ($X & $Z) | ($Y & (~ $Z)) ; // X AND Z OR Y AND NOT Z
    $calc = bindec($calc);
    return  $calc; 
}

function H($X, $Y, $Z){
    $X = hexbin($X);
    $Y = hexbin($Y);
    $Z = hexbin($Z);
    $calc = $X ^ $Y ^ $Z; // X XOR Y XOR Z
    $calc = bindec($calc);
    return  $calc; 
}

function I($X, $Y, $Z){
    $X = hexbin($X);
    $Y = hexbin($Y);
    $Z = hexbin($Z);
    $calc = $Y ^ ($X | (~ $Z)) ; // Y XOR (X OR NOT Z)
    $calc = bindec($calc);
    return  $calc; 
}

/* MD5 round functions */

/*
$A - hex, $B - hex, $C - hex, $D - hex (F - dec)
$M - binary
$s - decimal
$t - hex
*/
function FF(&$A, $B, $C, $D, $M, $s, $t){
    $A = hexdec($A);
    $t = hexdec($t);
    $M = bindec($M);
    $A = hexdec($B) + (($A + F($B, $C, $D) + $M + $t)); //decimal
    $A = rotate($A, $s);
}

function GG(&$A, $B, $C, $D, $M, $s, $t){
    $A = hexdec($A);
    $t = hexdec($t);
    $M = bindec($M);
    $A = hexdec($B) + (($A + G($B, $C, $D) + $M + $t)); //decimal
    $A = rotate($A, $s);
}

function HH(&$A, $B, $C, $D, $M, $s, $t){
    $A = hexdec($A);
    $t = hexdec($t);
    $M = bindec($M);
    $A = hexdec($B) + (($A + H($B, $C, $D) + $M + $t)); //decimal
    $A = rotate($A, $s);
}

function II(&$A, $B, $C, $D, $M, $s, $t){
    $A = hexdec($A);
    $t = hexdec($t);
    $M = bindec($M);
    $A = hexdec($B) + (($A + I($B, $C, $D) + $M + $t)); //decimal
    $A = rotate($A, $s);
}

// shift
function rotate($decimal, $bits) { //returns hex
  $binary = decbin($decimal);
  $shifted = substr($binary, $bits).substr($binary, 0, $bits);
  $hexshift = base_convert($shifted, 2, 16);
  return $hexshift;
}

function addVars(&$a, &$b, &$c, &$d, $A, $B, $C, $D){
    $A = hexdec($A);
    $B = hexdec($B);
    $C = hexdec($C);
    $D = hexdec($D);
    $aa = hexdec($a);
    $bb = hexdec($b);
    $cc = hexdec($c);
    $dd = hexdec($d);

    $aa = $aa + $A;
    $bb = $bb + $A;
    $cc = $cc + $A;
    $dd = $dd + $A;

    $a = dechex($aa);
    $b = dechex($bb);
    $c = dechex($cc);
    $d = dechex($dd);
}

?>

Answer 1

出于某种原因,这个问题并没有让我孤单,所以我仔细检查了你的代码并修复了错误,直到它工作:

在您完成此操作之前,我有两条建议:

1. 不要在int值和hex/bin表示之间来回转换; 在任何处理完成之前转换为int值; 使代码更具可读性.

2. 使用call_user_func()和实现GG - > G,II - > I只运行一次.

此外,还有一个微妙的bug; 仅由零个字符组成的输入字符串将无法正确编码; 我将解决这个问题作为读者的练习:-).

• 在init():

附加的是未填充消息的长度,以 位数表示,而不是字符数:

- $len = strlen($string)
+ $len = strlen($string) * 8;
  $hex = strhex($string); // convert ascii string to hex

另外,你必须填补你从中获得的内容,hexbin否则随后的调用str_split会使对齐错误:

- $bin = hexbin($hex);
+ $bin = leftpad(hexbin($hex), $len); // convert hex string to bin
  $block = str_split($padded, 32);

另外,字节顺序是小端:

+ foreach ($block as &$b) {
+     $b = implode('', array_reverse(str_split($b, 8)));
+ }

• 在strhex():

像这样有很多填充错误; dechex(ord("\1"))是'1'不是'01':

- $hex = $hex.dechex(ord($str[$i]));
+ $hex = $hex.leftpad(dechex(ord($str[$i])), 2);

• 在pad():

该字节阶是豆蔻端(你分成32位字),并truncate64()完全离线地图:-):

-   $bLen = decbin($len);
-  if(strlen($bLen) > 64){
-    $words = truncate64($bLen);
-    $bin .= $words[1].$words[0];
-  }
-  else{
-      while(strlen($bLen) < 64){
-        $bLen .= "0";
-      }
-    $words = str_split ($bLen, 32);
-    $bin .= $words[1].$words[0];
-  }
+ $bLen = leftpad(decbin($len), 64);
+ $bin .= implode('', array_reverse(str_split($bLen, 8)));

• 在F(),G(),H(),I():

位运算符不能用于二进制字符串:

- $X = hexbin($X);
- $Y = hexbin($Y);
- $Z = hexbin($Z);
- $calc = ...
- $calc = bindec($calc);
+ $X = hexdec($X);
+ $Y = hexdec($Y);
+ $Z = hexdec($Z);
+ $calc = ...

• 在FF(),GG(),HH(),II():

您$B在轮换之前添加,之后必须添加; 此外,由于您在字符串和int表示之间来回并且PHP_INT_SIZE可能大于4(例如,在64位平台上),您必须确保仅使用较低的32位:

- $A = hexdec($B) + (($A + H($B, $C, $D) + $M + $t)); //decimal
+ $A = ($A + H($B, $C, $D) + $M + $t) & 0xffffffff; //decimal
+ $A = rotate($A, $s);
+ $A = dechex((hexdec($B) + hexdec($A)) & 0xffffffff);

• 在addVars():

$A 每次添加都会重复,可能是复制粘贴工件:-):

- $aa = $aa + $A;
- $bb = $bb + $A;
- $cc = $cc + $A;
- $dd = $dd + $A;
+ $aa = ($aa + $A) & 0xffffffff;
+ $bb = ($bb + $B) & 0xffffffff;
+ $cc = ($cc + $C) & 0xffffffff;
+ $dd = ($dd + $D) & 0xffffffff;

• 在rotate():

旋转功能中有一个填充错误(再次).把它扔掉,换成:

+ function rotate ($decimal, $bits) { //returns hex
+     return dechex((($decimal << $bits) |  ($decimal >> (32 - $bits))) & 0xffffffff);
+ }

• 在MD():

最后但并非最不重要的是,您必须再次转换为小端:

- $MD5 = $a.$b.$c.$d;
+ $MD5 = '';
+ foreach (array($a, $b, $c, $d) as $x) {
+     $MD5 .= implode('', array_reverse(str_split(leftpad($x, 8), 2)));
+ }

缺少的leftpad()功能:

+ function leftpad($needs_padding, $alignment)
+ {
+   if (strlen($needs_padding) % $alignment) {
+       $pad_amount    = $alignment - strlen($needs_padding) % $alignment;
+       $left_pad      = implode('', array_fill(0, $pad_amount, '0'));
+       $needs_padding = $left_pad . $needs_padding;
+   }
+   return $needs_padding;
+ }

完整编辑的来源:

<?php

function MD($string){
$a = "67452301";
$b = "EFCDAB89";
$c = "98BADCFE";
$d = "10325476";

$words = init($string);

for($i = 0; $i <= count($words)/16-1; $i++){
        $A = $a;
        $B = $b;
        $C = $c;
        $D = $d;


        /* ROUND 1 */
        FF ($A, $B, $C, $D, $words[0 + ($i * 16)], 7, "d76aa478"); 
        FF ($D, $A, $B, $C, $words[1 + ($i * 16)], 12, "e8c7b756"); 
        FF ($C, $D, $A, $B, $words[2 + ($i * 16)], 17, "242070db"); 
        FF ($B, $C, $D, $A, $words[3 + ($i * 16)], 22, "c1bdceee"); 
        FF ($A, $B, $C, $D, $words[4 + ($i * 16)], 7, "f57c0faf"); 
        FF ($D, $A, $B, $C, $words[5 + ($i * 16)], 12, "4787c62a"); 
        FF ($C, $D, $A, $B, $words[6 + ($i * 16)], 17, "a8304613"); 
        FF ($B, $C, $D, $A, $words[7 + ($i * 16)], 22, "fd469501"); 
        FF ($A, $B, $C, $D, $words[8 + ($i * 16)], 7, "698098d8"); 
        FF ($D, $A, $B, $C, $words[9 + ($i * 16)], 12, "8b44f7af"); 
        FF ($C, $D, $A, $B, $words[10 + ($i * 16)], 17, "ffff5bb1"); 
        FF ($B, $C, $D, $A, $words[11 + ($i * 16)], 22, "895cd7be"); 
        FF ($A, $B, $C, $D, $words[12 + ($i * 16)], 7, "6b901122"); 
        FF ($D, $A, $B, $C, $words[13 + ($i * 16)], 12, "fd987193"); 
        FF ($C, $D, $A, $B, $words[14 + ($i * 16)], 17, "a679438e"); 
        FF ($B, $C, $D, $A, $words[15 + ($i * 16)], 22, "49b40821"); 

        /* ROUND 2 */
        GG ($A, $B, $C, $D, $words[1 + ($i * 16)], 5, "f61e2562"); 
        GG ($D, $A, $B, $C, $words[6 + ($i * 16)], 9, "c040b340"); 
        GG ($C, $D, $A, $B, $words[11 + ($i * 16)], 14, "265e5a51"); 
        GG ($B, $C, $D, $A, $words[0 + ($i * 16)], 20, "e9b6c7aa"); 
        GG ($A, $B, $C, $D, $words[5 + ($i * 16)], 5, "d62f105d"); 
        GG ($D, $A, $B, $C, $words[10 + ($i * 16)], 9, "02441453"); 
        GG ($C, $D, $A, $B, $words[15 + ($i * 16)], 14, "d8a1e681"); 
        GG ($B, $C, $D, $A, $words[4 + ($i * 16)], 20, "e7d3fbc8"); 
        GG ($A, $B, $C, $D, $words[9 + ($i * 16)], 5, "21e1cde6"); 
        GG ($D, $A, $B, $C, $words[14 + ($i * 16)], 9, "c33707d6"); 
        GG ($C, $D, $A, $B, $words[3 + ($i * 16)], 14, "f4d50d87"); 
        GG ($B, $C, $D, $A, $words[8 + ($i * 16)], 20, "455a14ed"); 
        GG ($A, $B, $C, $D, $words[13 + ($i * 16)], 5, "a9e3e905"); 
        GG ($D, $A, $B, $C, $words[2 + ($i * 16)], 9, "fcefa3f8"); 
        GG ($C, $D, $A, $B, $words[7 + ($i * 16)], 14, "676f02d9"); 
        GG ($B, $C, $D, $A, $words[12 + ($i * 16)], 20, "8d2a4c8a"); 

        /* ROUND 3 */
        HH ($A, $B, $C, $D, $words[5 + ($i * 16)], 4, "fffa3942"); 
        HH ($D, $A, $B, $C, $words[8 + ($i * 16)], 11, "8771f681"); 
        HH ($C, $D, $A, $B, $words[11 + ($i * 16)], 16, "6d9d6122"); 
        HH ($B, $C, $D, $A, $words[14 + ($i * 16)], 23, "fde5380c"); 
        HH ($A, $B, $C, $D, $words[1 + ($i * 16)], 4, "a4beea44"); 
        HH ($D, $A, $B, $C, $words[4 + ($i * 16)], 11, "4bdecfa9"); 
        HH ($C, $D, $A, $B, $words[7 + ($i * 16)], 16, "f6bb4b60"); 
        HH ($B, $C, $D, $A, $words[10 + ($i * 16)], 23, "bebfbc70"); 
        HH ($A, $B, $C, $D, $words[13 + ($i * 16)], 4, "289b7ec6"); 
        HH ($D, $A, $B, $C, $words[0 + ($i * 16)], 11, "eaa127fa"); 
        HH ($C, $D, $A, $B, $words[3 + ($i * 16)], 16, "d4ef3085"); 
        HH ($B, $C, $D, $A, $words[6 + ($i * 16)], 23, "04881d05"); 
        HH ($A, $B, $C, $D, $words[9 + ($i * 16)], 4, "d9d4d039"); 
        HH ($D, $A, $B, $C, $words[12 + ($i * 16)], 11, "e6db99e5"); 
        HH ($C, $D, $A, $B, $words[15 + ($i * 16)], 16, "1fa27cf8"); 
        HH ($B, $C, $D, $A, $words[2 + ($i * 16)], 23, "c4ac5665"); 

        /* ROUND 4 */
        II ($A, $B, $C, $D, $words[0 + ($i * 16)], 6, "f4292244"); 
        II ($D, $A, $B, $C, $words[7 + ($i * 16)], 10, "432aff97"); 
        II ($C, $D, $A, $B, $words[14 + ($i * 16)], 15, "ab9423a7"); 
        II ($B, $C, $D, $A, $words[5 + ($i * 16)], 21, "fc93a039"); 
        II ($A, $B, $C, $D, $words[12 + ($i * 16)], 6, "655b59c3"); 
        II ($D, $A, $B, $C, $words[3 + ($i * 16)], 10, "8f0ccc92"); 
        II ($C, $D, $A, $B, $words[10 + ($i * 16)], 15, "ffeff47d"); 
        II ($B, $C, $D, $A, $words[1 + ($i * 16)], 21, "85845dd1"); 
        II ($A, $B, $C, $D, $words[8 + ($i * 16)], 6, "6fa87e4f"); 
        II ($D, $A, $B, $C, $words[15 + ($i * 16)], 10, "fe2ce6e0"); 
        II ($C, $D, $A, $B, $words[6 + ($i * 16)], 15, "a3014314"); 
        II ($B, $C, $D, $A, $words[13 + ($i * 16)], 21, "4e0811a1"); 
        II ($A, $B, $C, $D, $words[4 + ($i * 16)], 6, "f7537e82"); 
        II ($D, $A, $B, $C, $words[11 + ($i * 16)], 10, "bd3af235"); 
        II ($C, $D, $A, $B, $words[2 + ($i * 16)], 15, "2ad7d2bb"); 
        II ($B, $C, $D, $A, $words[9 + ($i * 16)], 21, "eb86d391"); 

        addVars($a, $b, $c, $d, $A, $B, $C, $D);        
}
  $MD5 = '';
  foreach (array($a, $b, $c, $d) as $x) {
      $MD5 .= implode('', array_reverse(str_split(leftpad($x, 8), 2)));
  }

        return $MD5;
}

/* General functions */

function hexbin($str){
        $hexbinmap = array("0" => "0000"
                                                , "1" => "0001"
                                                , "2" => "0010"
                                                , "3" => "0011"
                                                , "4" => "0100"
                                                , "5" => "0101"
                                                , "6" => "0110"
                                                , "7" => "0111"
                                                , "8" => "1000"
                                                , "9" => "1001"
                                                , "A" => "1010"
                                                , "a" => "1010"
                                                , "B" => "1011"
                                                , "b" => "1011"
                                                , "C" => "1100"
                                                , "c" => "1100"
                                                , "D" => "1101"
                                                , "d" => "1101"
                                                , "E" => "1110"
                                                , "e" => "1110"
                                                , "F" => "1111"
                                                , "f" => "1111");

        $bin = "";
    for ($i = 0; $i < strlen($str); $i++)
    {
        $bin .= $hexbinmap[$str[$i]];
    }
    $bin = ltrim($bin, '0'); 
        // echo "Original: ".$str."  New: ".$bin."<br />";
    return $bin;
}

function strhex($str){
    $hex = "";
    for ($i = 0; $i < strlen($str); $i++)
    {
        $hex = $hex.leftpad(dechex(ord($str[$i])), 2);
    }
    return $hex;
}


/* MD5-specific functions */

function init($string){
        $len = strlen($string) * 8;
        $hex = strhex($string); // convert ascii string to hex
        $bin = leftpad(hexbin($hex), $len); // convert hex string to bin
        $padded = pad($bin);
        $padded = pad($padded, 1, $len);
        $block = str_split($padded, 32);

        foreach ($block as &$b) {
            $b = implode('', array_reverse(str_split($b, 8)));
        }

        return $block;
}

function pad($bin, $type=0, $len = 0){
        if($type == 0){
        $bin = $bin."1";
        $buff = strlen($bin) % 512;
        if($buff != 448){
                while(strlen($bin) % 512 != 448){

                        $bin = $bin."0";
                }
        }
        }
        // append length (b) of string to latter 64 bits
        elseif($type == 1){
            $bLen = leftpad(decbin($len), 64);
            $bin .= implode('', array_reverse(str_split($bLen, 8)));
        }
        return $bin;
}

/* MD5 base functions */

function F($X, $Y, $Z){
        $X = hexdec($X);
        $Y = hexdec($Y);
        $Z = hexdec($Z);
        $calc = (($X & $Y) | ((~ $X) & $Z)); // X AND Y OR NOT X AND Z
        return  $calc; 
}

function G($X, $Y, $Z){
        $X = hexdec($X);
        $Y = hexdec($Y);
        $Z = hexdec($Z);
        $calc = (($X & $Z) | ($Y & (~ $Z))); // X AND Z OR Y AND NOT Z
        return  $calc; 
}

function H($X, $Y, $Z){
        $X = hexdec($X);
        $Y = hexdec($Y);
        $Z = hexdec($Z);
        $calc = ($X ^ $Y ^ $Z); // X XOR Y XOR Z
        return  $calc; 
}

function I($X, $Y, $Z){
        $X = hexdec($X);
        $Y = hexdec($Y);
        $Z = hexdec($Z);
        $calc = ($Y ^ ($X | (~ $Z))) ; // Y XOR (X OR NOT Z)
        return  $calc; 
}

/* MD5 round functions */

/*
$A - hex, $B - hex, $C - hex, $D - hex (F - dec)
$M - binary
$s - decimal
$t - hex
*/
function FF(&$A, $B, $C, $D, $M, $s, $t){
        $A = hexdec($A);
        $t = hexdec($t);
        $M = bindec($M);
        $A = ($A + F($B, $C, $D) + $M + $t) & 0xffffffff; //decimal
        $A = rotate($A, $s);
        $A = dechex((hexdec($B) + hexdec($A)) & 0xffffffff);
}

function GG(&$A, $B, $C, $D, $M, $s, $t){
        $A = hexdec($A);
        $t = hexdec($t);
        $M = bindec($M);
        $A = ($A + G($B, $C, $D) + $M + $t) & 0xffffffff; //decimal
        $A = rotate($A, $s);
        $A = dechex((hexdec($B) + hexdec($A)) & 0xffffffff);
}

function HH(&$A, $B, $C, $D, $M, $s, $t){
        $A = hexdec($A);
        $t = hexdec($t);
        $M = bindec($M);
        $A = ($A + H($B, $C, $D) + $M + $t) & 0xffffffff; //decimal
        $A = rotate($A, $s);
        $A = dechex((hexdec($B) + hexdec($A)) & 0xffffffff);
}

function II(&$A, $B, $C, $D, $M, $s, $t){
        $A = hexdec($A);
        $t = hexdec($t);
        $M = bindec($M);
        $A = ($A + I($B, $C, $D) + $M + $t) & 0xffffffff; //decimal
        $A = rotate($A, $s);
        $A = dechex((hexdec($B) + hexdec($A)) & 0xffffffff);
}

// shift
function rotate ($decimal, $bits) { //returns hex
    return dechex((($decimal << $bits) |  ($decimal >> (32 - $bits))) & 0xffffffff);
}

function addVars(&$a, &$b, &$c, &$d, $A, $B, $C, $D){
        $A = hexdec($A);
        $B = hexdec($B);
        $C = hexdec($C);
        $D = hexdec($D);
        $aa = hexdec($a);
        $bb = hexdec($b);
        $cc = hexdec($c);
        $dd = hexdec($d);

        $aa = ($aa + $A) & 0xffffffff;
        $bb = ($bb + $B) & 0xffffffff;
        $cc = ($cc + $C) & 0xffffffff;
        $dd = ($dd + $D) & 0xffffffff;

        $a = dechex($aa);
        $b = dechex($bb);
        $c = dechex($cc);
        $d = dechex($dd);
}

function leftpad($needs_padding, $alignment)
{
    if (strlen($needs_padding) % $alignment) {
      $pad_amount    = $alignment - strlen($needs_padding) % $alignment;
      $left_pad      = implode('', array_fill(0, $pad_amount, '0'));
      $needs_padding = $left_pad . $needs_padding;
  }
  return $needs_padding;
}

Answer 2

对你有好感!我有类似的经历,很久以前我在Tcl中实现了MD5算法.我发现调试它的最好方法是逐行跟踪它,知道应该执行什么操作,并确保手动计算是否确实执行了正确的操作.

对此没有简单的答案,如果没有详细分析,就不可能从你发布的代码中分辨出可能出现的问题.

(我假设您已经了解了标准的md5()函数,并且您是出于学习目的而这样做.)