PHP暗号化ガイド

For every difficult and complicated 
question there is an answer 
that is simple, easily understood, 
and wrong. H.L. Mencken

string md5(string $str [, bool $raw_output ])

string crypt (string $str [, string $salt ])

string sha1 (string $str [, bool $raw_output ])

<?php
    
$file = 'textfile.txt';
$initial_contents = file_get_contents($file);  
   
if($initial_contents){
   
   $password = 'OctaviaAnghel';
   
   //Calculates the md5 hash 
   $md5_data = md5($password);
   
   //This function encrypts data
   $crypt = crypt($password);
   
   //Calculate the sha1 hash
   $sha1 = sha1($password);
   
   $encrypted_file = @fopen('encrypted.txt','w');
   $ok_encrypt
      = @fwrite($encrypted_file,'md5: '. $md5_data."\r¥".'crypt: 
          '.$crypt."\r¥".'sha1: '.$sha1);
   
   if($ok_encrypt){
      echo 'The encrypted code was succesfully created'.
      ' in encrypted_file.txt!!!'.'
';
   }
   else{
      echo ("The write of this file failed!");
   }
      
   @fclose($encrypted_file);
} 
?>  

// Listing file_encrypt.php
<?php
    
$file = 'textfile.txt';
$initial_contents = file_get_contents($file);  
   
if($initial_contents){
   
   //This function opens the module of the algorithm and 
   //the mode to be used
   $td = mcrypt_module_open('tripledes', '', 'ecb', '');
   
   //Create an initialization vector (IV) from a random source
   $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
   
   //This function initializes all buffers needed for encryption
   mcrypt_generic_init($td, $initial_contents, $iv);
   
   //This function encrypts data
   $encrypted_data = mcrypt_generic($td, $initial_contents); 
   
   $encrypted_file = @fopen('encrypted.txt','w');
   $ok_encrypt = @fwrite($encrypted_file,$encrypted_data);
   if($ok_encrypt){
      echo 'The encrypted code was succesfully created '.
      'in encrypted_file.txt!!!'.'<br />';
   }
   else{
      echo ("The write of this file failed!");
   }
      
   @fclose($encrypted_file);
   
   mcrypt_generic_init($td, $initial_contents, $iv);
   
   //This function decrypts data
   $p_t = mdecrypt_generic($td, $encrypted_data);
   
   $newfile = @fopen('newfile.txt','w');
   $ok_decrypt = @fwrite($newfile,$p_t);
   if($ok_decrypt){
      echo 'The decrypted code was succesfully created '.
      'in newfile.txt!!!'.'<br />';
   }
   else{
      echo ("The write of this file failed!");
   }
   @fclose($newfile);
    
   //This function deinitializes an encryption module
   mcrypt_generic_deinit($td);
   
   //Close the mcrypt module
   mcrypt_module_close($td);  
   } 
   
?>  

<?php
   
$file = 'textfile.txt';
$initial_contents = file_get_contents($file);
   
if($initial_contents){
   
   //mhash() applies a hash function specified by MHASH_MD5 
   //to the $initial_contents 
   $encrypted = mhash(MHASH_MD5, $initial_contents);
      
   // get current Unix timestamp
   $current = time();
   
   $salt = $current;
   $password = "Octavia";
   
   //mhash_keygen_s2k generates a key according to the hash function 
   //given and the password provided by the user. 
   $hash = mhash_keygen_s2k(MHASH_GOST, $password, $salt, 20);
   
   //concatenate the $salt with the $hash 
   $key = $salt . "|" . bin2hex($hash);
   
   $encrypted_file = @fopen('encrypted.txt','w');
   $ok_encrypt = @fwrite($encrypted_file,
      'mhash: '.bin2hex($encrypted).'  mhash_keygen_s2k:   
      '.$key);
      
   if($ok_encrypt){
      echo 'The encrypted code was succesfully created '. 
      'in encrypted_file.txt !!!'.'<br />';
   }
   else{
      echo ("The write of this file failed!");
   }
   @fclose($encrypted_file);
}
?>

> pear install pear_package_name

require_once 'Crypt/Blowfish.php';

<?php
   
require_once 'Crypt/Blowfish.php';
   
$file = 'textfile.txt';
$initial_contents = file_get_contents($file);
   
if($initial_contents){
   $bf = new Crypt_Blowfish('some secret key!');
   
   // Encrypts a string   
   $encrypted = $bf->encrypt($initial_contents); 
   
   $encrypted_file = @fopen('encrypted.txt','w');
   $ok_encrypt = @fwrite($encrypted_file,$encrypted);
   if($ok_encrypt){
      echo 'The encrypted code was succesfully created '.
      'in encrypted_file.txt!!!'.'<br />';
              }
   else{
      echo ("The write of this file failed!");
      }
   @fclose($encrypted_file);
   
   // Decrypts an encrypted string
   $plaintext = $bf->decrypt($encrypted); 
   $newfile = @fopen('newfile.txt','w');
   $ok_decrypt = @fwrite($newfile,$plaintext);
   if($ok_decrypt){
         echo 'The decrypted code was succesfully created '.
         'in newfile.txt!!!'.'<br />';
              }
   else{
      echo ("The write of this file failed!");
      }
      
   @fclose($newfile);
   }
?> 

> pear install pear_package_name

<?php
   
require_once 'Crypt/RSA.php';
   
//Generates the pair keys
function generate_key_pair()
{
   global $public_key,$private_key;
   
   $key_pair = new Crypt_RSA_KeyPair(32);
   
   //Returns public key from the pair
   $public_key = $key_pair->getPublicKey();
   
   //Returns private key from the pair
   $private_key = $key_pair->getPrivateKey();
}
   
//Check runtime errors
function check_error(&$obj)
{
   if ($obj->isError()){
      $error = $obj->getLastError();
      switch ($error->getCode()) {
      case CRYPT_RSA_ERROR_WRONG_TAIL :
         // nothing to do
         break;
      default:
         // echo error message and exit
         echo 'error: ', $error->getMessage();
         exit;
      }
   }
}
      
$file = 'textfile.txt';
   
generate_key_pair();  
$plain_text = file_get_contents($file);
      
//get string represenation of the public key
$key = Crypt_RSA_Key::fromString($public_key->toString()); 
      
$rsa_obj = new Crypt_RSA;
check_error($rsa_obj);
      
//Ecnrypts $plain_text by the key $key.
$encrypted = $rsa_obj->encrypt($plain_text, $key);
      
$encrypted_file = @fopen('encrypted.txt','w');
$ok_encrypt = fwrite($encrypted_file,$encrypted);
if($ok_encrypt){
   echo 'The encrypted code was succesfully created '.
   'in encrypted_file.txt!!!'.'<br />';
}
else{
   echo ("The write of this file failed!");
}
@fclose($encrypted_file);
      
$enc_text = $encrypted;
     
//Get string represenation of the private key
$key2 = Crypt_RSA_Key::fromString($private_key->toString());
check_error($key2);
      
//Check encrypting/decrypting function's behaviour
$rsa_obj->setParams(array('dec_key' => $key2));
check_error($rsa_obj);
   
//Decrypts $enc_text
$decrypted = $rsa_obj->decrypt($enc_text);
      
$newfile = @fopen('newfile.txt','w');
$ok_decrypt = @fwrite($newfile,$decrypted);
if($ok_decrypt){
   echo 'The decrypted code was succesfully created '.
   'in newfile.txt!!!'.'<br />';
}
else{
    echo ("The write of this file failed!");
}
@fclose($newfile);
    
?>

> pear install pear_package_name

<?php
      
require_once 'Crypt/HMAC.php';
   
//Creating a key by repeating the "0x0b" character for 20 times 
$key = str_repeat(chr(0x0b), 20);
   
//Creating an instance of the Crypt_HMAC class
//$crypt = new Crypt_HMAC($key, 'md5');
$crypt = new Crypt_HMAC($key, 'md5');
     
//Hashing function
echo $crypt->hash('Hello')."<br />";
   
$key = str_repeat(chr(0xaa), 10);
$data = str_repeat(chr(0xdd), 50);
   
//Sets key to use with hash
$crypt->setKey($key);
echo $crypt->hash($data)."¥";
?>

> pear install pear_package_name

<?php
   
//include Diffie Hellman functions
require_once 'Crypt/DiffieHellman.php';
   
//set the required options for two subjects
$subject_1 = array('prime'=>'123', 'generator'=>'7', 'private'=>'3');
$subject_2 = array('prime'=>'123', 'generator'=>'7', 'private'=>'34');
   
//apply Diffie Hellman algorithm
$subject_1_GK = new Crypt_DiffieHellman(
   $subject_1['prime'], $subject_1['generator'], 
   $subject_1['private']);
$subject_2_GK = new Crypt_DiffieHellman(
   $subject_2['prime'], $subject_2['generator'], 
   $subject_2['private']);
   
//generate keys      
$subject_1_GK->generateKeys();
$subject_2_GK->generateKeys();
   
//compute the secret keys     
$subject_1_SK = $subject_1_GK->computeSecretKey(
   $subject_2_GK->getPublicKey())->getSharedSecretKey();
$subject_2_SK = $subject_2_GK->computeSecretKey(
   $subject_1_GK->getPublicKey())->getSharedSecretKey();
   
//displaying the secret keys      
echo('Subject_1_SK:'.$subject_1_SK.'<br />');
echo('Subject_2_SK:'.$subject_2_SK);
?>      

<?php
   
//include Diffie Hellman functions
require_once 'Crypt/DiffieHellman.php';
   
//set the required options for two subjects
$subject_1 = array('prime' => 
   '9568094558049898340935098349053', 
   'generator'=>'2', 
   'private' => '2232370277237628823279273723742872289398723');
$subject_2 = array('prime' => 
   '9568094558049898340935098349053', 
   'generator'=>'2', 
   'private' => '0389237288721323987429834389298232433363463');
   
//apply Diffie Hellman algorithm
$subject_1_GK = new Crypt_DiffieHellman(
   $subject_1['prime'], $subject_1['generator'], 
   $subject_1['private']);
$subject_2_GK = new Crypt_DiffieHellman(
   $subject_2['prime'], $subject_2['generator'], 
   $subject_2['private']);
   
//generate keys    
$subject_1_GK->generateKeys();
$subject_2_GK->generateKeys(); 
   
//compute the secret keys using BINARY mode      
$subject_1_SK = $subject_1_GK->computeSecretKey(
   $subject_2_GK->getPublicKey(Crypt_DiffieHellman::BINARY), 
   Crypt_DiffieHellman::BINARY)->
   getSharedSecretKey(Crypt_DiffieHellman::BINARY);
$subject_2_SK = $subject_2_GK->computeSecretKey(
   $subject_1_GK->getPublicKey(Crypt_DiffieHellman::BINARY), 
   Crypt_DiffieHellman::BINARY)->
   getSharedSecretKey(Crypt_DiffieHellman::BINARY);
   
//display the secret keys    
echo('subject_1_SK:'.$subject_1_SK.'<br />');
echo('subject_2_SK:'.$subject_2_SK.'<br />');
   
?>