Detailed explanation of PHP encryption and decryption functions_php skills

Share a PHP encryption and decryption function. This function implements the function of encrypting some variable values.
The encryption code is as follows:

/* 
*功能：对字符串进行加密处理 
*参数一：需要加密的内容 
*参数二：密钥 
*/ 
function passport_encrypt($str,$key){ //加密函数 
  srand((double)microtime() * 1000000); 
  $encrypt_key=md5(rand(0, 32000)); 
  $ctr=0; 
  $tmp=''; 
  for($i=0;$i<strlen($str);$i++){ 
    $ctr=$ctr==strlen($encrypt_key)&#63;0:$ctr; 
    $tmp.=$encrypt_key[$ctr].($str[$i] ^ $encrypt_key[$ctr++]); 
  } 
  return base64_encode(passport_key($tmp,$key)); 
} 

The decryption code is as follows:

/* 
*功能：对字符串进行解密处理 
*参数一：需要解密的密文 
*参数二：密钥 
*/ 
function passport_decrypt($str,$key){ //解密函数 
  $str=passport_key(base64_decode($str),$key); 
  $tmp=''; 
  for($i=0;$i<strlen($str);$i++){ 
    $md5=$str[$i]; 
    $tmp.=$str[++$i] ^ $md5; 
  } 
  return $tmp; 
} 

Auxiliary function:

/* 
*辅助函数 
*/ 
function passport_key($str,$encrypt_key){ 
  $encrypt_key=md5($encrypt_key); 
  $ctr=0; 
  $tmp=''; 
  for($i=0;$i<strlen($str);$i++){ 
    $ctr=$ctr==strlen($encrypt_key)&#63;0:$ctr; 
    $tmp.=$str[$i] ^ $encrypt_key[$ctr++]; 
  } 
  return $tmp; 
} 

is used as follows:

$str='作者：余浩苗；电话：13611972365；电子邮件：123cvbz@163.com'; 
 
$key='hacker'; 
$encrypt=passport_encrypt($str,$key); 
$decrypt=passport_decrypt($encrypt,$key); 
 
echo '原文：',$str."<br><hr>"; 
echo '密文：',$encrypt."<br><hr>"; 
echo '译文：',$decrypt."<br><hr>"; 

The above is the PHP encryption and decryption function shared with you. I hope you like it and can apply it to your own learning.