Introduction to how to enable, encrypt and decrypt php mcrypt

 $str = "I am Li Yun";
 $key = "123qwe.019860905061X";
 $cipher = MCRYPT_RIJNDAEL_128;
 $mode = MCRYPT_MODE_ECB;
 $iv = mcrypt_creat e_iv(mcrypt_get_iv_size( $cipher,$mode),MCRYPT_RAND);

 echo "Original text:".$str."";
 $str_encrypt = mcrypt_encrypt($cipher,$key,$str,$mode,$iv);
 echo "The encrypted content is: ".$str_encrypt."";

 $str_decrypt = mcrypt_decrypt($cipher,$key,$str_encrypt,$mode,$iv);

 echo "After decryption Content: ".$str_decrypt."";
?>

Run the results: Original text: I am Li Yun The encrypted content is: B @鴹?=(I褣Z% Decrypted content: I am Li Yun

1) Before using the PHP encryption extension library Mcrypt to encrypt and decrypt data, first create an initialization vector, referred to as iv for short. From $iv = mcrypt_create_iv(mcrypt_get_iv_size($cipher,$modes),MCRYPT_RAND); it can be seen that creating an 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. The parameters cipher and mode refer to the algorithm and encryption mode respectively.

3), encryption function $str_encrypt = mcrypt_encrypt($cipher,$key,$str,$modes,$iv); The five parameters of this function are as follows: cipher——encryption algorithm, key——key, data( str)——data that needs to be encrypted, mode——algorithm mode, iv——initialization vector

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

//Writing in the manual:

 //Specify the size of the initialization vector iv:
 $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
 //Create the initialization vector:
 $iv = mcrypt_create_iv($iv_size, MCRY PT_RAND);
 //Encrypted password:
 $key = "123qwe.019860905061x";
 //Original content (unencrypted):
 $text = "My name is Adam Li!";
 echo $text. "n ";
 //Encrypted content:
 $crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $text, MCRYPT_MODE_ECB, $iv);
 echo $crypttext. "n";
 //Decrypt the encrypted content ：
 $str_decrypt = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $crypttext, MCRYPT_MODE_ECB, $iv);
 echo $str_decrypt;
//Original link http://bbs.it-home.org/article/7382.html
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Example of encryption/decryption request:

 $request_params = array(
 'controller' => 'todo',
 'action' => 'read',
 'username' => "bl",
 'userpass' => "a1"
 );

 $private_key = "28e336ac6c9423d946ba02d19c6a2632";

 //encrypt request
 $enc_request = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $ private_key, json_encode($request_params), MCRYPT_MODE_ECB));
 echo "CRYPT:".$enc_request."";

 //decrypt request
 $params = json_decode(trim(mcrypt_decrypt( MCRYPT_RIJNDAEL_256, $private_key, base64_decode($enc_request), MCRYPT_MODE_ECB )), true);
 echo "ENCRYPT:";

 //print result
 var_dump($params);
?>

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