PHP教程：php实现RSA加密类实例

<?php 
/**
 * RSA算法类
 * 签名及密文编码：base64字符串/十六进制字符串/二进制字符串流
 * 填充方式: PKCS1Padding(加解密)/NOPadding(解密)
 *
 * Notice:Only accepts a single block. Block size is equal to the RSA key size! 
 * 如密钥长度为1024 bit,则加密时数据需小于128字节,加上PKCS1Padding本身的11字节信息,所以明文需小于117字节
 *
 * @author: linvo
 * @version: 1.0.0
 * @date: 2013/1/23
 */ 
class RSA{ 
 private $pubKey = null; 
 private $priKey = null; 
 /**
  * 自定义错误处理
  */ 
 private function _error($msg){ 
  die('RSA Error:' . $msg); //TODO 
 } 
 /**
  * 构造函数
  *
  * @param string 公钥文件(验签和加密时传入)
  * @param string 私钥文件(签名和解密时传入)
  */ 
 public function __construct($public_key_file = '', $private_key_file = ''){
  if ($public_key_file){ 
   $this->_getPublicKey($public_key_file); 
  } 
  if ($private_key_file){ 
   $this->_getPrivateKey($private_key_file); 
  } 
 } 
 /**
  * 生成签名
  *
  * @param string 签名材料
  * @param string 签名编码(base64/hex/bin)
  * @return 签名值
  */ 
 public function sign($data, $code = 'base64'){ 
  $ret = false;
  if (openssl_sign($data, $ret, $this->priKey)){ 
   $ret = $this->_encode($ret, $code);
  }
  return $ret; 
 }
 /**
  * 验证签名
  *
  * @param string 签名材料
  * @param string 签名值
  * @param string 签名编码(base64/hex/bin)
  * @return bool 
  */ 
 public function verify($data, $sign, $code = 'base64'){ 
  $ret = false;
  $sign = $this->_decode($sign, $code);
  if ($sign !== false) {
   switch (openssl_verify($data, $sign, $this->pubKey)){ 
    case 1: $ret = true; break;
    case 0:  
    case -1:  
    default: $ret = false;  
   } 
  } 
  return $ret; 
 } 
 /**
  * 加密
  *
  * @param string 明文
  * @param string 密文编码(base64/hex/bin)
  * @param int 填充方式(貌似php有bug,所以目前仅支持OPENSSL_PKCS1_PADDING)
  * @return string 密文
  */ 
 public function encrypt($data, $code = 'base64', $padding = OPENSSL_PKCS1_PADDING){
  $ret = false;  
  if (!$this->_checkPadding($padding, 'en')) $this->_error('padding error');
  if (openssl_public_encrypt($data, $result, $this->pubKey, $padding)){
   $ret = $this->_encode($result, $code);
  } 
  return $ret; 
 } 
 /**
  * 解密
  *
  * @param string 密文
  * @param string 密文编码(base64/hex/bin)
  * @param int 填充方式(OPENSSL_PKCS1_PADDING / OPENSSL_NO_PADDING)
  * @param bool 是否翻转明文(When passing Microsoft CryptoAPI-generated RSA cyphertext, revert the bytes in the block)
  * @return string 明文
  */ 
 public function decrypt($data, $code = 'base64', $padding = OPENSSL_PKCS1_PADDING, $rev = false){
  $ret = false;
  $data = $this->_decode($data, $code);
  if (!$this->_checkPadding($padding, 'de')) $this->_error('padding error');
  if ($data !== false){ 
   if (openssl_private_decrypt($data, $result, $this->priKey, $padding)){
    $ret = $rev ? rtrim(strrev($result), "\0") : ''.$result;
   } 
  } 
  return $ret; 
 } 
 // 私有办法 
 /**
  * 检测填充类型
  * 加密只支持PKCS1_PADDING
  * 解密支持PKCS1_PADDING和NO_PADDING
  * 
  * @param int 填充模式
  * @param string 加密en/解密de
  * @return bool
  */ 
 private function _checkPadding($padding, $type){
  if ($type == 'en'){ 
   switch ($padding){ 
    case OPENSSL_PKCS1_PADDING: 
     $ret = true; 
     break; 
    default: 
     $ret = false; 
   } 
  } else { 
   switch ($padding){ 
    case OPENSSL_PKCS1_PADDING: 
    case OPENSSL_NO_PADDING: 
     $ret = true; 
     break; 
    default: 
     $ret = false; 
   } 
  } 
  return $ret; 
 } 
 private function _encode($data, $code){ 
  switch (strtolower($code)){ 
   case 'base64': 
    $data = base64_encode(''.$data);
    break; 
   case 'hex': 
    $data = bin2hex($data); 
    break; 
   case 'bin': 
   default: 
  } 
  return $data; 
 } 
 private function _decode($data, $code){ 
  switch (strtolower($code)){ 
   case 'base64': 
    $data = base64_decode($data); 
    break; 
   case 'hex': 
    $data = $this->_hex2bin($data); 
    break; 
   case 'bin': 
   default: 
  } 
  return $data; 
 } 
 private function _getPublicKey($file){ 
  $key_content = $this->_readFile($file);
  if ($key_content){ 
   $this->pubKey = openssl_get_publickey($key_content);
  } 
 } 
 private function _getPrivateKey($file){ 
  $key_content = $this->_readFile($file); 
  if ($key_content){ 
   $this->priKey = openssl_get_privatekey($key_content);
  }
 }
 private function _readFile($file){
  $ret = false;
  if (!file_exists($file)){
   $this->_error("The file {$file} is not exists");
  } else {
   $ret = file_get_contents($file);
  }
  return $ret;
 } 
 private function _hex2bin($hex = false){ 
  $ret = $hex !== false && preg_match('/^[0-9a-fA-F]+$/i', $hex) ? pack("H*", $hex) : false;
  return $ret; 
 } 
}

<?php 
header('Content-Type:text/html;Charset=utf-8;'); 
include "rsa.php"; 
echo '<pre>'; 
$a = isset($_GET['a']) ? $_GET['a'] : '测试123'; 
////////////////////////////////////// 
$pubfile = 'E:\ssl\cert\pwd.crt'; 
$prifile = 'E:\ssl\cert\pwd.pem'; 
$m = new RSA($pubfile, $prifile); 
$x = $m->sign($a); 
$y = $m->verify($a, $x); 
var_dump($x, $y); 
$x = $m->encrypt($a); 
$y = $m->decrypt($x); 
var_dump($x, $y);