Share installation and application tips of PHP encryption extension library Mcrypt_PHP tutorial

Among them, the Mcrypt extension library can implement encryption and decryption functions, that is, it can encrypt plain text and restore cipher text.

1. PHP encryption extension library Mcrypt installation

Mrcypt is not installed during the standard PHP installation process, but libmcrypt is included in the main directory of PHP. dll and libmhash.dll files (libmhash.dll is the Mhash extension library and can be installed together here). First, copy these two files to the system directory windowssystem32, then press the Ctrl+F shortcut key in the PHP.ini file to pop up the search box, and find; extension=php-mcrypt.dll and; extension=php_mhash.dll statement, then remove the preceding ";"; finally, save and restart the Apache server to take effect.

2. Algorithms and encryption modes of the PHP encryption extension library Mcrypt

The Mcrypt library supports more than 20 encryption algorithms and 8 encryption modes. You can use the function mcrypt_list_algorithms( ) and mcrypt_list_modes() to display, the results are as follows:

The algorithms supported by Mcrypt are: cast-128 gost rijndael-128 twofish arcfour cast-256 loki97 rijndael-192 saferplus wake blowfish-compat des rijndael-256 serpent xtea blowfish enigma rc2 tripledes

The encryption modes supported by Mcrypt are: cbc cfb ctr ecb ncfb nofb ofb stream

These algorithms and modes should be expressed as constants in the application, and prefixed when writing MCRYPT_ and MCRYPT_, as shown in the following Mcrypt application example:

DES algorithm is represented as MCRYPT_DES;
ECB mode is represented as MCRYPT_MODE_ECB;

3.PHP encryption extension Library Mcrypt application

First look at an example to understand the workflow of Mcrypt, and then look at the functions used in some processes:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><</span><span> ?php  </span></span></li><li><span>$</span><span class="attribute">str</span><span> = </span><span class="attribute-value">"我的名字是？一般人我不告诉他！"</span><span>;   </span></li><li class="alt"><span>//加密内容  </span></li><li><span>$</span><span class="attribute">key</span><span> = </span><span class="attribute-value">"key:111"</span><span>;   </span></li><li class="alt"><span>//密钥  </span></li><li><span>$</span><span class="attribute">cipher</span><span> = </span><span class="attribute-value">MCRYPT_DES</span><span>;  </span></li><li class="alt"><span>//密码类型  </span></li><li><span>$</span><span class="attribute">modes</span><span> = </span><span class="attribute-value">MCRYPT_MODE_ECB</span><span>;  </span></li><li class="alt"><span>//密码模式  </span></li><li><span>$</span><span class="attribute">iv</span><span> = </span><span class="attribute-value">mcrypt_create_iv</span><span>(mcrypt_get_iv_size<br />($cipher,$modes),MCRYPT_RAND);//初始化向量  </span></li><li class="alt"><span>echo "加密明文：".$str."</span><span class="tag"><</span><span class="tag-name">p</span><span class="tag">></span><span>";  </span></span></li>
<li>
<span>$</span><span class="attribute">str_encrypt</span><span> = </span><span class="attribute-value">mcrypt_encrypt</span><span>($cipher,<br>$key,$str,$modes,$iv);  </span>
</li>
<li class="alt"><span>//加密函数  </span></li>
<li>
<span>echo "加密密文：".$str_encrypt." </span><span class="tag"><</span><span class="tag-name">p</span><span class="tag">></span><span>";  </span>
</li>
<li class="alt">
<span>$</span><span class="attribute">str_decrypt</span><span> = </span><span class="attribute-value">mcrypt_decrypt</span><span>($cipher,<br>$key,$str_encrypt,$modes,$iv);  </span>
</li>
<li><span>//解密函数  </span></li>
<li class="alt"><span>echo "还原：".$str_decrypt;  </span></li>
<li>
<span class="tag">?></span><span> </span>
</li>
</ol>

Run results:

Encrypted plaintext: What is my name? I don’t tell most people!
Encrypted ciphertext: 锍 Bowl?]鸴?q榦軄L xiaoxianxian"簻黙
Restored: My name is? I won’t tell ordinary people!

<1>By As can be seen in the example, before using the PHP encryption extension library Mcrypt to encrypt and decrypt data, an initialization vector, referred to as iv for short, is created as shown in $iv = mcrypt_create_iv(mcrypt_get_iv_size($cipher,$modes),MCRYPT_RAND); The initialization vector requires two parameters: size specifies the size of iv; source is the source of iv, where the value MCRYPT_RAND is the system random number.

<2> The function mcrypt_get_iv_size($cipher,$modes) returns the initialization vector. Size, parameters cipher and mode refer to the algorithm and encryption mode respectively.

<3> Encryption function $str_encrypt = mcrypt_encrypt($cipher,$key,$str,$modes,$iv); 5 of this function. The parameters are as follows: cipher - encryption algorithm, key - key, data (str) - data to be encrypted, mode - algorithm mode, iv - initialization vector

<4> decryption Function mcrypt_decrypt($cipher,$key,$str_encrypt,$modes,$iv); The parameters of this function and the encryption function are almost the same. The only difference is data, which means that data is the data that needs to be decrypted $str_encrypt, not the original Data $str.

Note: The parameters cipher, key and mode in the encryption and decryption functions must correspond one to one, otherwise the data cannot be restored.

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