一、消息体加解密
微信公众平台在配置服务器时，提供了3种加解密的模式供开发者选择，即明文模式、兼容模式、安全模式,选择兼容模式和安全模式前，需在开发者中心填写消息加解密密钥EncodingAESKey。
- 明文模式：维持现有模式，没有适配加解密新特性，消息体明文收发，默认设置为明文模式
- 兼容模式：公众平台发送消息内容将同时包括明文和密文，消息包长度增加到原来的3倍左右；公众号回复明-文或密文均可，不影响现有消息收发；开发者可在此模式下进行调试
- 安全模式（推荐）：公众平台发送消息体的内容只含有密文，公众账号回复的消息体也为密文，建议开发者在调试成功后使用此模式收发消息
什么是EncodingAESKey？
- 微信公众平台采用AES对称加密算法对推送给公众帐号的消息体对行加密，EncodingAESKey则是加密所用的秘钥。公众帐号用此秘钥对收到的密文消息体进行解密，回复消息体也用此秘钥加密。
AES对称加密算法的原理可以参考 http://www.cnblogs.com/txw1958/p/aes.html
加解密的详细技术方案可以参考官方文档 http://mp.weixin.qq.com/wiki/index.php?title=%E6%8A%80%E6%9C%AF%E6%96%B9%E6%A1%88
二、开发实现及数据分析
1. 配置
假设本次的开发配置中URL为
http://www.fangbei.org/index.php
接口程序中需要配置以下三项参数
define("TOKEN", "weixin");
define("AppID", "wxbad0b45542aa0b5e");
define("EncodingAESKey", "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFG");
require_once('wxBizMsgCrypt.php');
2. 加解密实现
当用户向公众账号发送消息时，微信公众账号将会在URL中带上signature、timestamp、nonce、encrypt_type、msg_signature等参数，如下所示
http://www.fangbei.org/index.php?signature=35703636de2f9df2a77a662b68e521ce17c34db4×tamp=1414243737&nonce=1792106704&encrypt_type=aes&msg_signature=6147984331daf7a1a9eed6e0ec3ba69055256154
同时向该接口推送如下XML消息 ，即一个已加密的消息
<xml>
<ToUserName><![CDATA[gh_680bdefc8c5d]]></ToUserName>
<Encrypt><![CDATA[MNn4+jJ/VsFh2gUyKAaOJArwEVYCvVmyN0iXzNarP3O6vXzK62ft1/KG2/XPZ4y5bPWU/jfIfQxODRQ7sLkUsrDRqsWimuhIT8Eq+w4E/28m+XDAQKEOjWTQIOp1p6kNsIV1DdC3B+AtcKcKSNAeJDr7x7GHLx5DZYK09qQsYDOjP6R5NqebFjKt/NpEl/GU3gWFwG8LCtRNuIYdK5axbFSfmXbh5CZ6Bk5wSwj5fu5aS90cMAgUhGsxrxZTY562QR6c+3ydXxb+GHI5w+qA+eqJjrQqR7u5hS+1x5sEsA7vS+bZ5LYAR3+PZ243avQkGllQ+rg7a6TeSGDxxhvLw+mxxinyk88BNHkJnyK//hM1k9PuvuLAASdaud4vzRQlAmnYOslZl8CN7gjCjV41skUTZv3wwGPxvEqtm/nf5fQ=]]></Encrypt>
</xml>
这时，程序需要从url中获得以下参数
$timestamp = $_GET['timestamp'];
$nonce = $_GET["nonce"];
$msg_signature = $_GET['msg_signature'];
$encrypt_type = $_GET['encrypt_type'];
这些参数将用于加解密过程
收到消息后，先进行解密，解密部分代码如下
$postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
if ($encrypt_type == 'aes'){
$pc = new WXBizMsgCrypt(TOKEN, EncodingAESKey, AppID);
$this->logger(" D \r\n".$postStr);
$decryptMsg = ""; //解密后的明文
$errCode = $pc->DecryptMsg($msg_signature, $timestamp, $nonce, $postStr, $decryptMsg);
$postStr = $decryptMsg;
}
解密完成后，把解密内容又返回给$postStr，这是为了保证将消息中解密后的内容和明文模式时的消息统一，方便后续处理，解密后的XML如下
<xml>
<ToUserName><![CDATA[gh_680bdefc8c5d]]></ToUserName>
<FromUserName><![CDATA[oIDrpjpQ8j8mBuQ8nM26HWzNEZgg]]></FromUserName>
<CreateTime>1414243737</CreateTime>
<MsgType><![CDATA[text]]></MsgType>
<Content><![CDATA[?]]></Content>
<MsgId>6074130599188426998</MsgId>
</xml>
对消息在自己的原来代码中处理，完成之后，要回复的消息如下
<xml>
<ToUserName><![CDATA[oIDrpjpQ8j8mBuQ8nM26HWzNEZgg]]></ToUserName>
<FromUserName><![CDATA[gh_680bdefc8c5d]]></FromUserName>
<CreateTime>1414243733</CreateTime>
<MsgType><![CDATA[text]]></MsgType>
<Content><![CDATA[2014-10-25 21:28:53
testContent]]></Content>
</xml>
把上述消息进行加密，返回给微信公众账
//加密
if ($encrypt_type == 'aes'){
$encryptMsg = ''; //加密后的密文
$errCode = $pc->encryptMsg($result, $timeStamp, $nonce, $encryptMsg);
$result = $encryptMsg;
$this->logger(" E \r\n".$result);
}
加密后的内容如下
<xml>
<Encrypt><![CDATA[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]]></Encrypt>
<MsgSignature><![CDATA[6c46904dc1f58b2ddf2dd0399f1c6cf41f33ecb9]]></MsgSignature>
<TimeStamp>1414243733</TimeStamp>
<Nonce><![CDATA[1792106704]]></Nonce>
</xml>
这样，一个安全模式下的加解密消息就完成了。
三、完整代码
<?php
define("TOKEN", "weixin");
define("AppID", "wxbad0b45542aa0b5e");
define("EncodingAESKey", "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFG");
require_once('wxBizMsgCrypt.php');
$wechatObj = new wechatCallbackapiTest();
if (!isset($_GET['echostr'])) {
$wechatObj->responseMsg();
}else{
$wechatObj->valid();
}
class wechatCallbackapiTest
{
//验证签名
public function valid()
{
$echoStr = $_GET["echostr"];
$signature = $_GET["signature"];
$timestamp = $_GET["timestamp"];
$nonce = $_GET["nonce"];
$tmpArr = array(TOKEN, $timestamp, $nonce);
sort($tmpArr);
$tmpStr = implode($tmpArr);
$tmpStr = sha1($tmpStr);
if($tmpStr == $signature){
echo $echoStr;
exit;
}
}
//响应消息
public function responseMsg()
{
$timestamp = $_GET['timestamp'];
$nonce = $_GET["nonce"];
$msg_signature = $_GET['msg_signature'];
$encrypt_type = (isset($_GET['encrypt_type']) && ($_GET['encrypt_type'] == 'aes')) ? "aes" : "raw";
$postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
if (!empty($postStr)){
//解密
if ($encrypt_type == 'aes'){
$pc = new WXBizMsgCrypt(TOKEN, EncodingAESKey, AppID);
$this->logger(" D \r\n".$postStr);
$decryptMsg = ""; //解密后的明文
$errCode = $pc->DecryptMsg($msg_signature, $timestamp, $nonce, $postStr, $decryptMsg);
$postStr = $decryptMsg;
}
$this->logger(" R \r\n".$postStr);
$postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
$RX_TYPE = trim($postObj->MsgType);
//消息类型分离
switch ($RX_TYPE)
{
case "event":
$result = $this->receiveEvent($postObj);
break;
case "text":
$result = $this->receiveText($postObj);
break;
}
$this->logger(" R \r\n".$result);
//加密
if ($encrypt_type == 'aes'){
$encryptMsg = ''; //加密后的密文
$errCode = $pc->encryptMsg($result, $timeStamp, $nonce, $encryptMsg);
$result = $encryptMsg;
$this->logger(" E \r\n".$result);
}
echo $result;
}else {
echo "";
exit;
}
}
//接收事件消息
private function receiveEvent($object)
{
$content = "";
switch ($object->Event)
{
case "subscribe":
$content = "欢迎关注";
break;
}
$result = $this->transmitText($object, $content);
return $result;
}
//接收文本消息
private function receiveText($object)
{
$keyword = trim($object->Content);
if (strstr($keyword, "文本")){
$content = "这是个文本消息";
}else if (strstr($keyword, "单图文")){
$content = array();
$content[] = array("Title"=>"单图文标题", "Description"=>"单图文内容", "PicUrl"=>"http://discuz.comli.com/weixin/weather/icon/cartoon.jpg", "Url" =>"http://m.cnblogs.com/?u=txw1958");
}else if (strstr($keyword, "图文") || strstr($keyword, "多图文")){
$content = array();
$content[] = array("Title"=>"多图文1标题", "Description"=>"", "PicUrl"=>"http://discuz.comli.com/weixin/weather/icon/cartoon.jpg", "Url" =>"http://m.cnblogs.com/?u=txw1958");
$content[] = array("Title"=>"多图文2标题", "Description"=>"", "PicUrl"=>"http://d.hiphotos.bdimg.com/wisegame/pic/item/f3529822720e0cf3ac9f1ada0846f21fbe09aaa3.jpg", "Url" =>"http://m.cnblogs.com/?u=txw1958");
$content[] = array("Title"=>"多图文3标题", "Description"=>"", "PicUrl"=>"http://g.hiphotos.bdimg.com/wisegame/pic/item/18cb0a46f21fbe090d338acc6a600c338644adfd.jpg", "Url" =>"http://m.cnblogs.com/?u=txw1958");
}else if (strstr($keyword, "音乐")){
$content = array();
$content = array("Title"=>"最炫民族风", "Description"=>"歌手：凤凰传奇", "MusicUrl"=>"http://121.199.4.61/music/zxmzf.mp3", "HQMusicUrl"=>"http://121.199.4.61/music/zxmzf.mp3");
}else{
$content = date("Y-m-d H:i:s",time())."\n".$object->FromUserName;
}
if(is_array($content)){
if (isset($content[0])){
$result = $this->transmitNews($object, $content);
}else if (isset($content['MusicUrl'])){
$result = $this->transmitMusic($object, $content);
}
}else{
$result = $this->transmitText($object, $content);
}
return $result;
}
//回复文本消息
private function transmitText($object, $content)
{
$xmlTpl = "<xml>
<ToUserName><![CDATA[%s]]></ToUserName>
<FromUserName><![CDATA[%s]]></FromUserName>
<CreateTime>%s</CreateTime>
<MsgType><![CDATA[text]]></MsgType>
<Content><![CDATA[%s]]></Content>
</xml>";
$result = sprintf($xmlTpl, $object->FromUserName, $object->ToUserName, time(), $content);
return $result;
}
//回复图文消息
private function transmitNews($object, $newsArray)
{
if(!is_array($newsArray)){
return;
}
$itemTpl = " <item>
<Title><![CDATA[%s]]></Title>
<Description><![CDATA[%s]]></Description>
<PicUrl><![CDATA[%s]]></PicUrl>
<Url><![CDATA[%s]]></Url>
</item>
";
$item_str = "";
foreach ($newsArray as $item){
$item_str .= sprintf($itemTpl, $item['Title'], $item['Description'], $item['PicUrl'], $item['Url']);
}
$xmlTpl = "<xml>
<ToUserName><![CDATA[%s]]></ToUserName>
<FromUserName><![CDATA[%s]]></FromUserName>
<CreateTime>%s</CreateTime>
<MsgType><![CDATA[news]]></MsgType>
<ArticleCount>%s</ArticleCount>
<Articles>
$item_str </Articles>
</xml>";
$result = sprintf($xmlTpl, $object->FromUserName, $object->ToUserName, time(), count($newsArray));
return $result;
}
//回复音乐消息
private function transmitMusic($object, $musicArray)
{
$itemTpl = "<Music>
<Title><![CDATA[%s]]></Title>
<Description><![CDATA[%s]]></Description>
<MusicUrl><![CDATA[%s]]></MusicUrl>
<HQMusicUrl><![CDATA[%s]]></HQMusicUrl>
</Music>";
$item_str = sprintf($itemTpl, $musicArray['Title'], $musicArray['Description'], $musicArray['MusicUrl'], $musicArray['HQMusicUrl']);
$xmlTpl = "<xml>
<ToUserName><![CDATA[%s]]></ToUserName>
<FromUserName><![CDATA[%s]]></FromUserName>
<CreateTime>%s</CreateTime>
<MsgType><![CDATA[music]]></MsgType>
$item_str
</xml>";
$result = sprintf($xmlTpl, $object->FromUserName, $object->ToUserName, time());
return $result;
}
//日志记录
public function logger($log_content)
{
if(isset($_SERVER['HTTP_APPNAME'])){ //SAE
sae_set_display_errors(false);
sae_debug($log_content);
sae_set_display_errors(true);
}else if($_SERVER['REMOTE_ADDR'] != "127.0.0.1"){ //LOCAL
$max_size = 500000;
$log_filename = "log.xml";
if(file_exists($log_filename) and (abs(filesize($log_filename)) > $max_size)){unlink($log_filename);}
file_put_contents($log_filename, date('Y-m-d H:i:s').$log_content."\r\n", FILE_APPEND);
}
}
}
?>
转自：https://www.cnblogs.com/txw1958/p/weixin-aes-encrypt-Decrypt.html
