wordpress用户密码加密原理及其算法分析

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转载请注明本文出处：http://blog.csdn.net/hk_jh/article/details/27368279

1、什么是wordpress？

关于wordpress的介绍请自行参照维基百科：http://zh.wikipedia.org/wiki/Wordpress

其实只要掌握了其加密原理，再用高效的语言实现之，暴力破解不就很容易了吗？

2、wordpress用户密码的加密算法

首先，wordpress是开源的，大家可以从官网下载源代码。另外wordpress是用php语言编写的。

wordpress用户密码加密后的密文格式：

$P$BcSda3/tRXQcRZMPj3cUI0jZJFdMgL0 
$P$BNclJc4wbM.vSjKPYxKggDPtw3siXQ0 

以下是其解压后文件夹/include下的class-phpass.php文件的代码，主要包含了对用户密码进行加密的类及函数；

<?php/** * Portable PHP password hashing framework. * @package phpass * @since 2.5.0 * @version 0.3 / WordPress * @link http://www.openwall.com/phpass/ */## Written by Solar Designer <solar at openwall.com> in 2004-2006 and placed in# the public domain.  Revised in subsequent years, still public domain.## There's absolutely no warranty.## Please be sure to update the Version line if you edit this file in any way.# It is suggested that you leave the main version number intact, but indicate# your project name (after the slash) and add your own revision information.## Please do not change the "private" password hashing method implemented in# here, thereby making your hashes incompatible.  However, if you must, please# change the hash type identifier (the "$P$") to something different.## Obviously, since this code is in the public domain, the above are not# requirements (there can be none), but merely suggestions.#/** * Portable PHP password hashing framework. * * @package phpass * @version 0.3 / WordPress * @link http://www.openwall.com/phpass/ * @since 2.5.0 */class PasswordHash {var $itoa64;var $iteration_count_log2;var $portable_hashes;var $random_state;function PasswordHash($iteration_count_log2, $portable_hashes){$this->itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';if ($iteration_count_log2 < 4 || $iteration_count_log2 > 31)$iteration_count_log2 = 8;$this->iteration_count_log2 = $iteration_count_log2;$this->portable_hashes = $portable_hashes;$this->random_state = microtime() . uniqid(rand(), TRUE); // removed getmypid() for compatibility reasons}function get_random_bytes($count){$output = '';if ( @is_readable('/dev/urandom') &&    ($fh = @fopen('/dev/urandom', 'rb'))) {$output = fread($fh, $count);fclose($fh);}if (strlen($output) < $count) {$output = '';for ($i = 0; $i < $count; $i += 16) {$this->random_state =    md5(microtime() . $this->random_state);$output .=    pack('H*', md5($this->random_state));}$output = substr($output, 0, $count);}return $output;}function encode64($input, $count){$output = '';$i = 0;do {$value = ord($input[$i++]);$output .= $this->itoa64[$value & 0x3f];if ($i < $count)$value |= ord($input[$i]) << 8;$output .= $this->itoa64[($value >> 6) & 0x3f];if ($i++ >= $count)break;if ($i < $count)$value |= ord($input[$i]) << 16;$output .= $this->itoa64[($value >> 12) & 0x3f];if ($i++ >= $count)break;$output .= $this->itoa64[($value >> 18) & 0x3f];} while ($i < $count);return $output;}function gensalt_private($input){$output = '$P$';$output .= $this->itoa64[min($this->iteration_count_log2 +((PHP_VERSION >= '5') ? 5 : 3), 30)];$output .= $this->encode64($input, 6);return $output;}function crypt_private($password, $setting){$output = '*0';if (substr($setting, 0, 2) == $output)$output = '*1';$id = substr($setting, 0, 3);# We use "$P$", phpBB3 uses "$H$" for the same thingif ($id != '$P$' && $id != '$H$')return $output;$count_log2 = strpos($this->itoa64, $setting[3]);if ($count_log2 < 7 || $count_log2 > 30)return $output;$count = 1 << $count_log2;$salt = substr($setting, 4, 8);if (strlen($salt) != 8)return $output;# We're kind of forced to use MD5 here since it's the only# cryptographic primitive available in all versions of PHP# currently in use.  To implement our own low-level crypto# in PHP would result in much worse performance and# consequently in lower iteration counts and hashes that are# quicker to crack (by non-PHP code).if (PHP_VERSION >= '5') {$hash = md5($salt . $password, TRUE);do {$hash = md5($hash . $password, TRUE);} while (--$count);} else {$hash = pack('H*', md5($salt . $password));do {$hash = pack('H*', md5($hash . $password));} while (--$count);}$output = substr($setting, 0, 12);$output .= $this->encode64($hash, 16);return $output;}function gensalt_extended($input){$count_log2 = min($this->iteration_count_log2 + 8, 24);# This should be odd to not reveal weak DES keys, and the# maximum valid value is (2**24 - 1) which is odd anyway.$count = (1 << $count_log2) - 1;$output = '_';$output .= $this->itoa64[$count & 0x3f];$output .= $this->itoa64[($count >> 6) & 0x3f];$output .= $this->itoa64[($count >> 12) & 0x3f];$output .= $this->itoa64[($count >> 18) & 0x3f];$output .= $this->encode64($input, 3);return $output;}function gensalt_blowfish($input){# This one needs to use a different order of characters and a# different encoding scheme from the one in encode64() above.# We care because the last character in our encoded string will# only represent 2 bits.  While two known implementations of# bcrypt will happily accept and correct a salt string which# has the 4 unused bits set to non-zero, we do not want to take# chances and we also do not want to waste an additional byte# of entropy.$itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';$output = '$2a$';$output .= chr(ord('0') + $this->iteration_count_log2 / 10);$output .= chr(ord('0') + $this->iteration_count_log2 % 10);$output .= '$';$i = 0;do {$c1 = ord($input[$i++]);$output .= $itoa64[$c1 >> 2];$c1 = ($c1 & 0x03) << 4;if ($i >= 16) {$output .= $itoa64[$c1];break;}$c2 = ord($input[$i++]);$c1 |= $c2 >> 4;$output .= $itoa64[$c1];$c1 = ($c2 & 0x0f) << 2;$c2 = ord($input[$i++]);$c1 |= $c2 >> 6;$output .= $itoa64[$c1];$output .= $itoa64[$c2 & 0x3f];} while (1);return $output;}function HashPassword($password){$random = '';if (CRYPT_BLOWFISH == 1 && !$this->portable_hashes) {$random = $this->get_random_bytes(16);$hash =    crypt($password, $this->gensalt_blowfish($random));if (strlen($hash) == 60)return $hash;}if (CRYPT_EXT_DES == 1 && !$this->portable_hashes) {if (strlen($random) < 3)$random = $this->get_random_bytes(3);$hash =    crypt($password, $this->gensalt_extended($random));if (strlen($hash) == 20)return $hash;}if (strlen($random) < 6)$random = $this->get_random_bytes(6);$hash =    $this->crypt_private($password,    $this->gensalt_private($random));if (strlen($hash) == 34)return $hash;# Returning '*' on error is safe here, but would _not_ be safe# in a crypt(3)-like function used _both_ for generating new# hashes and for validating passwords against existing hashes.return '*';}function CheckPassword($password, $stored_hash){$hash = $this->crypt_private($password, $stored_hash);if ($hash[0] == '*')$hash = crypt($password, $stored_hash);return $hash === $stored_hash;}}?>

3、算法分析

（1）wordpress密码加密后的密文格式：
$P$B12345678huiyw4r7qhfuhs8yjmd6ef
$P$912345678huiyw4r7qhfuhs8yjmd6ef


第一段：$P$格式固定
第二段：只有一个字符。若php版本大于5.0则为B，否则为9
第三段：8位salt
第四段：22位，真正加密后的密码


（2）密文的加密方法
php版本高于5.0

$hash = md5($salt . $password, TRUE);do{$hash = md5($hash . $password, TRUE);} while (--$count);

［注］“.”在php中是连接运算
参数TRUR表示加密结果取16字节二进制
count取2的13次方：8192


php版本低于5.0

$hash = pack('H*', md5($salt . $password));do {$hash = pack('H*', md5($hash . $password));} while (--$count);

［注］php低于5.0 md5返回的是32位十六进制字符串形式
pack（H＊） 将md5结果转化为二进制
count取2的11次方：2048


上述方法得到的 $hash 再进行base64加密：
（3）wordpress的base64算法
64位字符表比较特殊，与普通的字符表顺序有差异：
itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';


//input即hash，count＝16

function encode64($input, $count){$output = '';$i = 0;do {$value = ord($input[$i++]);//返回第一个字符的acsii值$output .= $this->itoa64[$value & 0x3f];if ($i < $count)$value |= ord($input[$i]) << 8;$output .= $this->itoa64[($value >> 6) & 0x3f];if ($i++ >= $count)break;if ($i < $count)$value |= ord($input[$i]) << 16;$output .= $this->itoa64[($value >> 12) & 0x3f];if ($i++ >= $count)break;$output .= $this->itoa64[($value >> 18) & 0x3f];} while ($i < $count);return $output;}

上述方法即可得到22位加密后的密码

4、用C实现wordpress的加密

以下是本人自己用C实现的代码，如有错误，敬请指正！

wordpress.c 文件：

#include <stdio.h>#include <string.h>#include "md5.h"#include "wordpress.h"#define WORDPRESS_MD5_CHAR_NUM 16unsigned char base64Char[] = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";void md5_to_unsigned_char(unsigned char *hash){int i;unsigned char md5[17];for (i = 0; i < 16; i++){if (hash[2*i] >= '0' && hash[2*i] <= '9')md5[i] = (hash[2*i] - '0') << 4;else if (hash[2*i] >= 'a' && hash[2*i] <= 'f')md5[i] = (hash[2*i] - 'a') <<4;if (hash[2*i+1] >= '0' && hash[2*i+1] <= '9')md5[i] = md5[i] | ((hash[2*i+1] - '0') & 0x0f);else if (hash[2*i+1] >= 'a' && hash[2*i+1] <= 'f')md5[i] = md5[i] | ((hash[2*i+1] - 'a') & 0x0f);}md5[16] = '\0';for (i = 0; i < 16; i++)hash[i] = md5[i];hash[16] = '\0';}void base64Encode(unsigned char *md5, unsigned char *result){int num_24bits = 5;int i;  for (i = 0; i < num_24bits; ++i){result[4 * i + 0] = base64Char[(md5[3 * i] >> 2) & 0x3F];  result[4 * i + 1] = base64Char[(((md5[3 * i] & 0x3) << 4) | (md5[3 * i + 1] >> 4)) & 0x3F];  result[4 * i + 2] = base64Char[((md5[3 * i + 1] << 2) | (md5[3 * i + 2] >> 6)) & 0x3F];  result[4 * i + 3] = base64Char[md5[3 * i + 2] & 0x3F];}result[20] = base64Char[md5[15] >> 2];result[21] = base64Char[(md5[15] << 4) & 0x3F];result[22] = '\0';}  int wordpress( unsigned char * salt, unsigned char *passwd, int count, unsigned char *code ){int i, j;char symbol;unsigned char buffer[100];unsigned char base64_code[23];int len = strlen( (char *)passwd );if (strlen( (char *)salt ) != 8){printf("illegal salt!\n");return 1;}if (count != 8192 && count != 2048){printf("illegal count!\n");return 1;}//first time use md5 function with saltstrcpy( (char *)buffer, (char *)salt );strcat( (char *)buffer, (char *)passwd );MD5( buffer, strlen( (char *)buffer), buffer, 0 );md5_to_unsigned_char( buffer );//count times md5 functionfor (i = 0; i < count; i++){memcpy( (void *)&buffer[WORDPRESS_MD5_CHAR_NUM], passwd, len );MD5( buffer, WORDPRESS_MD5_CHAR_NUM + len, buffer, 0 );md5_to_unsigned_char( buffer );}memcpy( (void *)code, buffer, 32);base64Encode( buffer, base64_code );if (count == 8192)symbol = 'B';else if(count == 2048)symbol = '9';strcpy( (char *)code, "$P$" );code[3] = symbol;code[4] = '\0';strcat( (char *)code, (char *)salt);memcpy( (void *)&code[12], base64_code, 22);return 0;}

附上以前自己写的md5代码：

#include "md5.h"#include <stdio.h>#include <memory.h>#include <string.h>#define F(x,y,z) ((x & y) | (~x & z))  #define G(x,y,z) ((x & z) | (y & ~z))  #define H(x,y,z) (x^y^z)  #define I(x,y,z) (y ^ (x | ~z))  #define ROTATE_LEFT(x,n) ((x << n) | (x >> (32-n)))  #define FF(a,b,c,d,x,s,ac) \{ \    a += F(b,c,d) + x + ac; \    a = ROTATE_LEFT(a,s); \    a += b; \}#define GG(a,b,c,d,x,s,ac) \{ \    a += G(b,c,d) + x + ac; \    a = ROTATE_LEFT(a,s); \    a += b; \}#define HH(a,b,c,d,x,s,ac) \{ \    a += H(b,c,d) + x + ac; \    a = ROTATE_LEFT(a,s); \    a += b; \}#define II(a,b,c,d,x,s,ac) \{ \    a += I(b,c,d) + x + ac; \    a = ROTATE_LEFT(a,s); \    a += b; \}                                              void MD5Init(MD5_CTX *context);void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen);void MD5Final(MD5_CTX *context,unsigned char digest[16]);void MD5Transform(unsigned int state[4],unsigned char block[64]);void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len);void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len);           unsigned char PADDING[]={0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};          void MD5Init(MD5_CTX *context)    {        context->count[0] = 0;        context->count[1] = 0;        context->state[0] = 0x67452301;        context->state[1] = 0xEFCDAB89;        context->state[2] = 0x98BADCFE;        context->state[3] = 0x10325476;    }    void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen)      {          unsigned int i = 0,index = 0,partlen = 0;          index = (context->count[0] >> 3) & 0x3F;          partlen = 64 - index;          context->count[0] += inputlen << 3;          if(context->count[0] < (inputlen << 3))              context->count[1]++;          context->count[1] += inputlen >> 29;                if(inputlen >= partlen)          {              memcpy(&context->buffer[index],input,partlen);              MD5Transform(context->state,context->buffer);              for(i = partlen;i+64 <= inputlen;i+=64)                  MD5Transform(context->state,&input[i]);              index = 0;                  }            else          {              i = 0;          }          memcpy(&context->buffer[index],&input[i],inputlen-i);      }      void MD5Final(MD5_CTX *context,unsigned char digest[16])      {          unsigned int index = 0,padlen = 0;          unsigned char bits[8];          index = (context->count[0] >> 3) & 0x3F;          padlen = (index < 56)?(56-index):(120-index);          MD5Encode(bits,context->count,8);          MD5Update(context,PADDING,padlen);          MD5Update(context,bits,8);          MD5Encode(digest,context->state,16);      }      void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len)      {          unsigned int i = 0,j = 0;          while(j < len)          {              output[j] = input[i] & 0xFF;                output[j+1] = (input[i] >> 8) & 0xFF;              output[j+2] = (input[i] >> 16) & 0xFF;              output[j+3] = (input[i] >> 24) & 0xFF;              i++;              j+=4;          }      }      void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len)    {          unsigned int i = 0,j = 0;          while(j < len)          {              output[i] = (input[j]) |                  (input[j+1] << 8) |                  (input[j+2] << 16) |                  (input[j+3] << 24);              i++;              j+=4;           }      }      void MD5Transform(unsigned int state[4],unsigned char block[64])    {          unsigned int a = state[0];          unsigned int b = state[1];          unsigned int c = state[2];          unsigned int d = state[3];          unsigned int x[64];          MD5Decode(x,block,64);          FF(a, b, c, d, x[ 0], 7, 0xd76aa478);           FF(d, a, b, c, x[ 1], 12, 0xe8c7b756);           FF(c, d, a, b, x[ 2], 17, 0x242070db);           FF(b, c, d, a, x[ 3], 22, 0xc1bdceee);           FF(a, b, c, d, x[ 4], 7, 0xf57c0faf);           FF(d, a, b, c, x[ 5], 12, 0x4787c62a);           FF(c, d, a, b, x[ 6], 17, 0xa8304613);           FF(b, c, d, a, x[ 7], 22, 0xfd469501);           FF(a, b, c, d, x[ 8], 7, 0x698098d8);           FF(d, a, b, c, x[ 9], 12, 0x8b44f7af);           FF(c, d, a, b, x[10], 17, 0xffff5bb1);           FF(b, c, d, a, x[11], 22, 0x895cd7be);           FF(a, b, c, d, x[12], 7, 0x6b901122);           FF(d, a, b, c, x[13], 12, 0xfd987193);           FF(c, d, a, b, x[14], 17, 0xa679438e);           FF(b, c, d, a, x[15], 22, 0x49b40821);                           GG(a, b, c, d, x[ 1], 5, 0xf61e2562);           GG(d, a, b, c, x[ 6], 9, 0xc040b340);           GG(c, d, a, b, x[11], 14, 0x265e5a51);           GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa);           GG(a, b, c, d, x[ 5], 5, 0xd62f105d);           GG(d, a, b, c, x[10], 9,  0x2441453);           GG(c, d, a, b, x[15], 14, 0xd8a1e681);           GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8);           GG(a, b, c, d, x[ 9], 5, 0x21e1cde6);           GG(d, a, b, c, x[14], 9, 0xc33707d6);           GG(c, d, a, b, x[ 3], 14, 0xf4d50d87);           GG(b, c, d, a, x[ 8], 20, 0x455a14ed);           GG(a, b, c, d, x[13], 5, 0xa9e3e905);           GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8);           GG(c, d, a, b, x[ 7], 14, 0x676f02d9);           GG(b, c, d, a, x[12], 20, 0x8d2a4c8a);                           HH(a, b, c, d, x[ 5], 4, 0xfffa3942);           HH(d, a, b, c, x[ 8], 11, 0x8771f681);           HH(c, d, a, b, x[11], 16, 0x6d9d6122);           HH(b, c, d, a, x[14], 23, 0xfde5380c);           HH(a, b, c, d, x[ 1], 4, 0xa4beea44);           HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9);           HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60);           HH(b, c, d, a, x[10], 23, 0xbebfbc70);           HH(a, b, c, d, x[13], 4, 0x289b7ec6);           HH(d, a, b, c, x[ 0], 11, 0xeaa127fa);           HH(c, d, a, b, x[ 3], 16, 0xd4ef3085);           HH(b, c, d, a, x[ 6], 23,  0x4881d05);           HH(a, b, c, d, x[ 9], 4, 0xd9d4d039);           HH(d, a, b, c, x[12], 11, 0xe6db99e5);           HH(c, d, a, b, x[15], 16, 0x1fa27cf8);           HH(b, c, d, a, x[ 2], 23, 0xc4ac5665);                           II(a, b, c, d, x[ 0], 6, 0xf4292244);           II(d, a, b, c, x[ 7], 10, 0x432aff97);           II(c, d, a, b, x[14], 15, 0xab9423a7);           II(b, c, d, a, x[ 5], 21, 0xfc93a039);           II(a, b, c, d, x[12], 6, 0x655b59c3);           II(d, a, b, c, x[ 3], 10, 0x8f0ccc92);           II(c, d, a, b, x[10], 15, 0xffeff47d);           II(b, c, d, a, x[ 1], 21, 0x85845dd1);           II(a, b, c, d, x[ 8], 6, 0x6fa87e4f);           II(d, a, b, c, x[15], 10, 0xfe2ce6e0);           II(c, d, a, b, x[ 6], 15, 0xa3014314);        II(b, c, d, a, x[13], 21, 0x4e0811a1);           II(a, b, c, d, x[ 4], 6, 0xf7537e82);        II(d, a, b, c, x[11], 10, 0xbd3af235);        II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb);        II(b, c, d, a, x[ 9], 21, 0xeb86d391);        state[0] += a;        state[1] += b;        state[2] += c;        state[3] += d;    } void MD5(unsigned char * buf, unsigned int len, unsigned char *out, int type){    int i;    MD5_CTX md5;    unsigned char digest[16];    char hex[]="0123456789abcdef";    char HEX[]="0123456789ABCDEF";    MD5Init(&md5);    MD5Update(&md5, buf,len);    MD5Final(&md5, digest);    if (type == 0)    {            for (i = 0; i < 16; i++)         {            out[i+i]   = hex[digest[i] >> 4];            out[i+i+1] = hex[digest[i] & 0x0f];        }    }    else if (type == 1)    {        for (i = 0; i < 16; i++)         {            out[i+i]   = HEX[digest[i] >> 4];            out[i+i+1] = HEX[digest[i] & 0x0f];        }    }    out[i+i] = '\0';}

测试代码：

#include <stdio.h>#include "wordpress.h"int main(){unsigned char passwd[] = "12345678";unsigned char salt[] = "12345687";unsigned char code[40];wordpress(salt, passwd, 8192, code);printf("code: %s\n", code);return 0;}