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PHP可逆加密解密算法

WBOY
Release: 2016-06-20 13:03:23
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对于大部分密码加密,我们可以采用md5、sha1等方法。可以有效防止数据泄露,但是这些方法仅适用于无需还原的数据加密。

对于需要还原的信息,则需要采用可逆的加密解密算法。

下面一组PHP函数是实现此加密解密的方法:

加密算法如下:

function encrypt($data, $key)
{
	$key	=	md5($key);
    $x		=	0;
    $len	=	strlen($data);
    $l		=	strlen($key);
    for ($i = 0; $i < $len; $i++)
    {
        if ($x == $l) 
        {
        	$x = 0;
        }
        $char .= $key{$x};
        $x++;
    }
    for ($i = 0; $i < $len; $i++)
    {
        $str .= chr(ord($data{$i}) + (ord($char{$i})) % 256);
    }
    return base64_encode($str);
}
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解密算法如下:

function decrypt($data, $key)
{
	$key = md5($key);
    $x = 0;
    $data = base64_decode($data);
    $len = strlen($data);
    $l = strlen($key);
    for ($i = 0; $i < $len; $i++)
    {
        if ($x == $l) 
        {
        	$x = 0;
        }
        $char .= substr($key, $x, 1);
        $x++;
    }
    for ($i = 0; $i < $len; $i++)
    {
        if (ord(substr($data, $i, 1)) < ord(substr($char, $i, 1)))
        {
            $str .= chr((ord(substr($data, $i, 1)) + 256) - ord(substr($char, $i, 1)));
        }
        else
        {
            $str .= chr(ord(substr($data, $i, 1)) - ord(substr($char, $i, 1)));
        }
    }
    return $str;
}
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上述加密解密的过程均需要用到一个加密密钥(即参数$key)。

$data = &#39;PHP加密解密算法&#39;; // 被加密信息 

$key = &#39;123&#39;; // 密钥 

$encrypt = encrypt($data, $key); 

$decrypt = decrypt($encrypt, $key); 

echo $encrypt, "\n", 

$decrypt;
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上述将输出类似如下结果:

gniCSOzZG+HnS9zcFea7SefNGhXF
PHP加密解密算法

从上述结果可以看出,这是一组可逆的加密解密算法,可以用于部分需要还原的数据加密。


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