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HomeBackend DevelopmentPHP TutorialPHP封装的字符串加密解密函数_php技巧

程序中经常使用的PHP加密解密字符串函数

代码如下:

/*********************************************************************
 函数名称:encrypt
 函数作用:加密解密字符串
 使用方法:
 加密  :encrypt('str','E','nowamagic');
 解密  :encrypt('被加密过的字符串','D','nowamagic');
 参数说明:
 $string :需要加密解密的字符串
 $operation:判断是加密还是解密:E:加密 D:解密
 $key  :加密的钥匙(密匙);
*********************************************************************/
 function encrypt($string,$operation,$key='')
 {
  $key=md5($key);
  $key_length=strlen($key);
  $string=$operation=='D'?base64_decode($string):substr(md5($string.$key),0,8).$string;
  $string_length=strlen($string);
  $rndkey=$box=array();
  $result='';
  for($i=0;$i<=255;$i++)
  {
   $rndkey[$i]=ord($key[$i%$key_length]);
   $box[$i]=$i;
  }
  for($j=$i=0;$i<256;$i++)
  {
   $j=($j+$box[$i]+$rndkey[$i])%256;
   $tmp=$box[$i];
   $box[$i]=$box[$j];
   $box[$j]=$tmp;
  }
  for($a=$j=$i=0;$i<$string_length;$i++)
  {
   $a=($a+1)%256;
   $j=($j+$box[$a])%256;
   $tmp=$box[$a];
   $box[$a]=$box[$j];
   $box[$j]=$tmp;
   $result.=chr(ord($string[$i])^($box[($box[$a]+$box[$j])%256]));
  }
  if($operation=='D')
  {
   if(substr($result,0,8)==substr(md5(substr($result,8).$key),0,8))
   {
    return substr($result,8);
   }
   else
   {
    return'';
   }
  }
  else
  {
   return str_replace('=','',base64_encode($result));
  }
 }

使用方法:

$id = 132;
 
$token = encrypt($id, 'E', 'a');
 
echo '加密:'.encrypt($id, 'E', 'a');
echo '<br />';
 
echo '解密:'.encrypt($token, 'D', 'a');

非常给力的authcode加密函数,Discuz!经典代码(带详解):

function authcode($string, $operation = 'DECODE', $key = '', $expiry = 0) {  
  // 动态密匙长度,相同的明文会生成不同密文就是依靠动态密匙  
  $ckey_length = 4;  
    
  // 密匙  
  $key = md5($key &#63; $key : $GLOBALS['discuz_auth_key']);  
    
  // 密匙a会参与加解密  
  $keya = md5(substr($key, 0, 16));  
  // 密匙b会用来做数据完整性验证  
  $keyb = md5(substr($key, 16, 16));  
  // 密匙c用于变化生成的密文  
  $keyc = $ckey_length &#63; ($operation == 'DECODE' &#63; substr($string, 0, $ckey_length):
substr(md5(microtime()), -$ckey_length)) : '';  
  // 参与运算的密匙  
  $cryptkey = $keya.md5($keya.$keyc);  
  $key_length = strlen($cryptkey);  
  // 明文,前10位用来保存时间戳,解密时验证数据有效性,10到26位用来保存$keyb(密匙b), 
//解密时会通过这个密匙验证数据完整性  
  // 如果是解码的话,会从第$ckey_length位开始,因为密文前$ckey_length位保存 动态密匙,以保证解密正确  
  $string = $operation == 'DECODE' &#63; base64_decode(substr($string, $ckey_length)) : 
sprintf('%010d', $expiry &#63; $expiry + time() : 0).substr(md5($string.$keyb), 0, 16).$string;  
  $string_length = strlen($string);  
  $result = '';  
  $box = range(0, 255);  
  $rndkey = array();  
  // 产生密匙簿  
  for($i = 0; $i <= 255; $i++) {  
    $rndkey[$i] = ord($cryptkey[$i % $key_length]);  
  }  
  // 用固定的算法,打乱密匙簿,增加随机性,好像很复杂,实际上对并不会增加密文的强度  
  for($j = $i = 0; $i < 256; $i++) {  
    $j = ($j + $box[$i] + $rndkey[$i]) % 256;  
    $tmp = $box[$i];  
    $box[$i] = $box[$j];  
    $box[$j] = $tmp;  
  }  
  // 核心加解密部分  
  for($a = $j = $i = 0; $i < $string_length; $i++) {  
    $a = ($a + 1) % 256;  
    $j = ($j + $box[$a]) % 256;  
    $tmp = $box[$a];  
    $box[$a] = $box[$j];  
    $box[$j] = $tmp;  
    // 从密匙簿得出密匙进行异或,再转成字符  
    $result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));  
  }  
  if($operation == 'DECODE') { 
    // 验证数据有效性,请看未加密明文的格式  
    if((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) && 
substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, 16)) {  
      return substr($result, 26);  
    } else {  
      return '';  
    }  
  } else {  
    // 把动态密匙保存在密文里,这也是为什么同样的明文,生产不同密文后能解密的原因  
    // 因为加密后的密文可能是一些特殊字符,复制过程可能会丢失,所以用base64编码  
    return $keyc.str_replace('=', '', base64_encode($result));  
  }  
}

函数authcode($string, $operation, $key, $expiry)中的$string:字符串,明文或密文;$operation:DECODE表示解密,其它表示加密;$key:密匙;$expiry:密文有效期。

用法:

$str = 'abcdef'; 
$key = 'www.helloweba.com'; 
echo authcode($str,'ENCODE',$key,0); //加密 
$str = '56f4yER1DI2WTzWMqsfPpS9hwyoJnFP2MpC8SOhRrxO7BOk'; 
echo authcode($str,'DECODE',$key,0); //解密

3、加解密函数encrypt():

function encrypt($string,$operation,$key=''){ 
  $key=md5($key); 
  $key_length=strlen($key); 
   $string=$operation=='D'&#63;base64_decode($string):substr(md5($string.$key),0,8).$string; 
  $string_length=strlen($string); 
  $rndkey=$box=array(); 
  $result=''; 
  for($i=0;$i<=255;$i++){ 
      $rndkey[$i]=ord($key[$i%$key_length]); 
    $box[$i]=$i; 
  } 
  for($j=$i=0;$i<256;$i++){ 
    $j=($j+$box[$i]+$rndkey[$i])%256; 
    $tmp=$box[$i]; 
    $box[$i]=$box[$j]; 
    $box[$j]=$tmp; 
  } 
  for($a=$j=$i=0;$i<$string_length;$i++){ 
    $a=($a+1)%256; 
    $j=($j+$box[$a])%256; 
    $tmp=$box[$a]; 
    $box[$a]=$box[$j]; 
    $box[$j]=$tmp; 
    $result.=chr(ord($string[$i])^($box[($box[$a]+$box[$j])%256])); 
  } 
  if($operation=='D'){ 
    if(substr($result,0,8)==substr(md5(substr($result,8).$key),0,8)){ 
      return substr($result,8); 
    }else{ 
      return''; 
    } 
  }else{ 
    return str_replace('=','',base64_encode($result)); 
  } 
}

函数encrypt($string,$operation,$key)中$string:需要加密解密的字符串;$operation:判断是加密还是解密,E表示加密,D表示解密;$key:密匙。

用法:

$str = 'abc'; 
$key = 'www.helloweba.com'; 
$token = encrypt($str, 'E', $key); 
echo '加密:'.encrypt($str, 'E', $key); 
echo '解密:'.encrypt($str, 'D', $key);

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