在密碼學中,加密(英語:Encryption)是將明文信息改變爲難以讀取的密文內容,使之不可讀的過程。只有擁有解密方法的對象,經由解密過程,才能將密文還原爲正常可讀的內容。php
加密技術的重點是加密算法,加密算法主要分爲三類:算法
加密過程:數組
優勢:安全
缺點:bash
經常使用算法:網絡
$cipher_list = mcrypt_list_algorithms();//mcrypt支持的加密算法列表
$mode_list = mcrypt_list_modes();//mcrypt支持的加密模式列表
// print_r($cipher_list);
// print_r($mode_list);
function encrypt($key,$data){
$td = mcrypt_module_open("des", "", "ecb", "");//使用MCRYPT_DES算法,ecb模式
$size = mcrypt_enc_get_iv_size($td); //設置初始向量的大小
$iv = mcrypt_create_iv($size,MCRYPT_RAND); //建立初始向量
$key_size = mcrypt_enc_get_key_size($td); //返回所支持的最大的密鑰長度(以字節計算)
$salt = '';
$subkey = substr(md5(md5($key).$salt), 0,$key_size);//對key複雜處理,並設置長度
mcrypt_generic_init($td, $subkey, $iv);
$endata = mcrypt_generic($td, $data);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
return $endata;
}
function decrypt($key,$endata){
$td = mcrypt_module_open("des", "", "ecb", "");//使用MCRYPT_DES算法,ecb模式
$size = mcrypt_enc_get_iv_size($td); //設置初始向量的大小
$iv = mcrypt_create_iv($size,MCRYPT_RAND); //建立初始向量
$key_size = mcrypt_enc_get_key_size($td); //返回所支持的最大的密鑰長度(以字節計算)
$salt = '';
$subkey = substr(md5(md5($key).$salt), 0,$key_size);//對key複雜處理,並設置長度
mcrypt_generic_init($td, $subkey, $iv);
$data = rtrim(mdecrypt_generic($td, $endata)).'\n';
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
return $data;
}
$key = "www.tencent.com";
// $data = "返回所支持的最大的密鑰長度(涉及到發件費啦";
$data = "dadfafdafd,我是一個好孩子";
$endata = encrypt($key,$data);
$data1 = decrypt($key,$endata);
echo $endata; //直接輸出,在網頁上是亂碼,用base64_encode處理,就變成由字符、數組、加號、斜槓等共64種字符註冊
echo base64_encode($endata);
echo $data1;
複製代碼
<?php
/**
* 使用openssl實現非對稱加密
*/
class Rsa {
/**
* private key
*/
private $_privKey;
/**
* public key
*/
private $_pubKey;
/**
* the keys saving path
*/
private $_keyPath;
/**
* the construtor,the param $path is the keys saving path
*/
public function __construct($path) {
if (empty($path) || !is_dir($path)) {
throw new Exception('Must set the keys save path');
}
$this->_keyPath = $path;
}
/**
* create the key pair,save the key to $this->_keyPath
* 也可使用openssl命令生成公鑰私鑰
* openssl genrsa -out rsa_private_key.pem 1024
* openssl rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem
*/
public function createKey() {
$r = openssl_pkey_new();
openssl_pkey_export($r, $privKey);
file_put_contents($this->_keyPath . DIRECTORY_SEPARATOR . 'priv.key', $privKey);
$this->_privKey = openssl_pkey_get_public($privKey);
$rp = openssl_pkey_get_details($r);
$pubKey = $rp['key'];
file_put_contents($this->_keyPath . DIRECTORY_SEPARATOR . 'pub.key', $pubKey);
$this->_pubKey = openssl_pkey_get_public($pubKey);
}
/**
* setup the private key
*/
public function setupPrivKey() {
if (is_resource($this->_privKey)) {
return true;
}
$file = $this->_keyPath . DIRECTORY_SEPARATOR . 'priv.key';
$prk = file_get_contents($file);
$this->_privKey = openssl_pkey_get_private($prk);
return true;
}
/**
* setup the public key
*/
public function setupPubKey() {
if (is_resource($this->_pubKey)) {
return true;
}
$file = $this->_keyPath . DIRECTORY_SEPARATOR . 'pub.key';
$puk = file_get_contents($file);
$this->_pubKey = openssl_pkey_get_public($puk);
return true;
}
/**
* encrypt with the private key
*/
public function privEncrypt($data) {
if (!is_string($data)) {
return null;
}
$this->setupPrivKey();
$r = openssl_private_encrypt($data, $encrypted, $this->_privKey);
if ($r) {
return base64_encode($encrypted);
}
return null;
}
/**
* decrypt with the private key
*/
public function privDecrypt($encrypted) {
if (!is_string($encrypted)) {
return null;
}
$this->setupPrivKey();
$encrypted = base64_decode($encrypted);
$r = openssl_private_decrypt($encrypted, $decrypted, $this->_privKey);
if ($r) {
return $decrypted;
}
return null;
}
/**
* encrypt with public key
*/
public function pubEncrypt($data) {
if (!is_string($data)) {
return null;
}
$this->setupPubKey();
$r = openssl_public_encrypt($data, $encrypted, $this->_pubKey);
if ($r) {
return base64_encode($encrypted);
}
return null;
}
/**
* decrypt with the public key
*/
public function pubDecrypt($crypted) {
if (!is_string($crypted)) {
return null;
}
$this->setupPubKey();
$crypted = base64_decode($crypted);
$r = openssl_public_decrypt($crypted, $decrypted, $this->_pubKey);
if ($r) {
return $decrypted;
}
return null;
}
public function __destruct() {
@fclose($this->_privKey);
@fclose($this->_pubKey);
}
}
//如下是一個簡單的測試demo,若是不須要請刪除
$rsa = new Rsa('ssl-key');
//私鑰加密,公鑰解密
echo 'source:我是老鱉<br />';
$pre = $rsa->privEncrypt('我是老鱉');
echo 'private encrypted:<br />' . $pre . '<br />';
$pud = $rsa->pubDecrypt($pre);
echo 'public decrypted:' . $pud . '<br />';
//公鑰加密,私鑰解密
echo 'source:幹IT的<br />';
$pue = $rsa->pubEncrypt('幹IT的');
echo 'public encrypt:<br />' . $pue . '<br />';
$prd = $rsa->privDecrypt($pue);
echo 'private decrypt:' . $prd;
?>
複製代碼
加密過程當中不須要使用密鑰,輸入明文後由系統直接通過加密算法處理成密文,這種加密後的數據是沒法被解密的,只有從新輸入明文,並再次通過一樣不可逆的加密算法處理,獲得相同的加密密文並被系統從新識別後,才能真正解密。 經常使用算法有 md5, crypt,sha1分佈式
<?php
$data = 'hello';
echo md5($data); //輸出32位的16進制 5d41402abc4b2a76b9719d911017c592
複製代碼
//以不一樣散列類型使用 crypt()
<?php
if (CRYPT_STD_DES == 1) {
echo 'Standard DES: ' . crypt('rasmuslerdorf', 'rl') . "\n";
}
if (CRYPT_EXT_DES == 1) {
echo 'Extended DES: ' . crypt('rasmuslerdorf', '_J9..rasm') . "\n";
}
if (CRYPT_MD5 == 1) {
echo 'MD5: ' . crypt('rasmuslerdorf', '$1$rasmusle$') . "\n";
}
if (CRYPT_BLOWFISH == 1) {
echo 'Blowfish: ' . crypt('rasmuslerdorf', '$2a$07$usesomesillystringforsalt$') . "\n";
}
if (CRYPT_SHA256 == 1) {
echo 'SHA-256: ' . crypt('rasmuslerdorf', '$5$rounds=5000$usesomesillystringforsalt$') . "\n";
}
if (CRYPT_SHA512 == 1) {
echo 'SHA-512: ' . crypt('rasmuslerdorf', '$6$rounds=5000$usesomesillystringforsalt$') . "\n";
}
?>
以上輸出
Standard DES: rl.3StKT.4T8M
Extended DES: _J9..rasmBYk8r9AiWNc
MD5: $1$rasmusle$rISCgZzpwk3UhDidwXvin0
Blowfish: $2a$07$usesomesillystringfore2uDLvp1Ii2e./U9C8sBjqp8I90dH6hi
SHA-256: $5$rounds=5000$usesomesillystri$KqJWpanXZHKq2BOB43TSaYhEWsQ1Lr5QNyPCDH/Tp.6
SHA-512: $6$rounds=5000$usesomesillystri$D4IrlXatmP7rx3P3InaxBeoomnAihCKRVQP22JZ6EY47Wc6BkroIuUUBOov1i.S5KPgErtP/EN5mcO.ChWQW21
複製代碼
<?php
$data="hello";
echo sha1($data); // aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d
//固然,能夠將多種加密算法混合使用
echo md5(sha1($data));
//輸出:e69d7e620e82be5eb414d1f8d1d4b9d9
//這種方式的雙重加密也能夠提升數據的安全性
複製代碼