/**
* 对公众平台发送给公众账号的消息加解密示例代码.
*
* @copyright Copyright (c) 1998-2014 Tencent Inc.
*/
// ------------------------------------------------------------------------
/**
* 针对org.apache.commons.codec.binary.Base64，
* 需要导入架包commons-codec-1.9（或commons-codec-1.8等其他版本）
* 官方下载地址：http://commons.apache.org/proper/commons-codec/download_codec.cgi
*/
package me.chanjar.weixin.common.util.crypto;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.digest.DigestUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.InputSource;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.StringReader;
import java.nio.charset.Charset;
import java.security.NoSuchAlgorithmException;
import java.util.*;
public class WxCryptUtil {
private static final Base64 base64 = new Base64();
private static final Charset CHARSET = Charset.forName("utf-8");
private static final ThreadLocal<DocumentBuilder> builderLocal =
new ThreadLocal<DocumentBuilder>() {
@Override protected DocumentBuilder initialValue() {
try {
return DocumentBuilderFactory.newInstance().newDocumentBuilder();
} catch (ParserConfigurationException exc) {
throw new IllegalArgumentException(exc);
}
}
};
protected byte[] aesKey;
protected String token;
protected String appidOrCorpid;
public WxCryptUtil() {
super();
}
/**
* 构造函数
*
* @param token 公众平台上，开发者设置的token
* @param encodingAesKey 公众平台上，开发者设置的EncodingAESKey
* @param appidOrCorpid 公众平台appid/corpid
*/
public WxCryptUtil(String token, String encodingAesKey, String appidOrCorpid) {
this.token = token;
this.appidOrCorpid = appidOrCorpid;
this.aesKey = Base64.decodeBase64(encodingAesKey + "=");
}
/**
* 将公众平台回复用户的消息加密打包.
* <ol>
* <li>对要发送的消息进行AES-CBC加密</li>
* <li>生成安全签名</li>
* <li>将消息密文和安全签名打包成xml格式</li>
* </ol>
*
* @param plainText 公众平台待回复用户的消息，xml格式的字符串
* @return 加密后的可以直接回复用户的密文，包括msg_signature, timestamp, nonce, encrypt的xml格式的字符串
*/
public String encrypt(String plainText) {
// 加密
String encryptedXml = encrypt(genRandomStr(), plainText);
// 生成安全签名
String timeStamp = timeStamp = Long.toString(System.currentTimeMillis() / 1000l);
String nonce = genRandomStr();
try {
String signature = SHA1.gen(token, timeStamp, nonce, encryptedXml);
String result = generateXml(encryptedXml, signature, timeStamp, nonce);
return result;
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
}
}
/**
* 对明文进行加密.
*
* @param plainText 需要加密的明文
* @return 加密后base64编码的字符串
*/
protected String encrypt(String randomStr, String plainText) {
ByteGroup byteCollector = new ByteGroup();
byte[] randomStringBytes = randomStr.getBytes(CHARSET);
byte[] plainTextBytes = plainText.getBytes(CHARSET);
byte[] bytesOfSizeInNetworkOrder = number2BytesInNetworkOrder(plainTextBytes.length);
byte[] appIdBytes = appidOrCorpid.getBytes(CHARSET);
// randomStr + networkBytesOrder + text + appid
byteCollector.addBytes(randomStringBytes);
byteCollector.addBytes(bytesOfSizeInNetworkOrder);
byteCollector.addBytes(plainTextBytes);
byteCollector.addBytes(appIdBytes);
// ... + pad: 使用自定义的填充方式对明文进行补位填充
byte[] padBytes = PKCS7Encoder.encode(byteCollector.size());
byteCollector.addBytes(padBytes);
// 获得最终的字节流, 未加密
byte[] unencrypted = byteCollector.toBytes();
try {
// 设置加密模式为AES的CBC模式
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
SecretKeySpec keySpec = new SecretKeySpec(aesKey, "AES");
IvParameterSpec iv = new IvParameterSpec(aesKey, 0, 16);
cipher.init(Cipher.ENCRYPT_MODE, keySpec, iv);
// 加密
byte[] encrypted = cipher.doFinal(unencrypted);
// 使用BASE64对加密后的字符串进行编码
String base64Encrypted = base64.encodeToString(encrypted);
return base64Encrypted;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
/**
* 检验消息的真实性，并且获取解密后的明文.
* <ol>
* <li>利用收到的密文生成安全签名，进行签名验证</li>
* <li>若验证通过，则提取xml中的加密消息</li>
* <li>对消息进行解密</li>
* </ol>
*
* @param msgSignature 签名串，对应URL参数的msg_signature
* @param timeStamp 时间戳，对应URL参数的timestamp
* @param nonce 随机串，对应URL参数的nonce
* @param encryptedXml 密文，对应POST请求的数据
* @return 解密后的原文
*/
public String decrypt(String msgSignature, String timeStamp, String nonce, String encryptedXml) {
// 密钥，公众账号的app corpSecret
// 提取密文
String cipherText = extractEncryptPart(encryptedXml);
try {
// 验证安全签名
String signature = SHA1.gen(token, timeStamp, nonce, cipherText);
if (!signature.equals(msgSignature)) {
throw new RuntimeException("加密消息签名校验失败");
}
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
}
// 解密
String result = decrypt(cipherText);
return result;
}
/**
* 对密文进行解密.
*
* @param cipherText 需要解密的密文
* @return 解密得到的明文
*/
public String decrypt(String cipherText) {
byte[] original;
try {
// 设置解密模式为AES的CBC模式
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
SecretKeySpec key_spec = new SecretKeySpec(aesKey, "AES");
IvParameterSpec iv = new IvParameterSpec(Arrays.copyOfRange(aesKey, 0, 16));
cipher.init(Cipher.DECRYPT_MODE, key_spec, iv);
// 使用BASE64对密文进行解码
byte[] encrypted = Base64.decodeBase64(cipherText);
// 解密
original = cipher.doFinal(encrypted);
} catch (Exception e) {
throw new RuntimeException(e);
}
String xmlContent, from_appid;
try {
// 去除补位字符
byte[] bytes = PKCS7Encoder.decode(original);
// 分离16位随机字符串,网络字节序和AppId
byte[] networkOrder = Arrays.copyOfRange(bytes, 16, 20);
int xmlLength = bytesNetworkOrder2Number(networkOrder);
xmlContent = new String(Arrays.copyOfRange(bytes, 20, 20 + xmlLength), CHARSET);
from_appid = new String(Arrays.copyOfRange(bytes, 20 + xmlLength, bytes.length),
CHARSET);
} catch (Exception e) {
throw new RuntimeException(e);
}
// appid不相同的情况
if (!from_appid.equals(appidOrCorpid)) {
throw new RuntimeException("AppID不正确");
}
return xmlContent;
}
/**
* 微信公众号支付签名算法(详见:http://pay.weixin.qq.com/wiki/doc/api/index.php?chapter=4_3)
* @param packageParams 原始参数
* @param signKey 加密Key(即 商户Key)
* @param charset 编码
* @return 签名字符串
*/
public static String createSign(Map<String, String> packageParams, String signKey) {
SortedMap<String, String> sortedMap = new TreeMap<String, String>();
sortedMap.putAll(packageParams);
List<String> keys = new ArrayList<String>(packageParams.keySet());
Collections.sort(keys);
StringBuffer toSign = new StringBuffer();
for (String key : keys) {
String value = packageParams.get(key);
if (null != value && !"".equals(value) && !"sign".equals(key)
&& !"key".equals(key)) {
toSign.append(key + "=" + value + "&");
}
}
toSign.append("key=" + signKey);
String sign = DigestUtils.md5Hex(toSign.toString())
.toUpperCase();
return sign;
}
/**
* 将一个数字转换成生成4个字节的网络字节序bytes数组
*
* @param number
*/
private byte[] number2BytesInNetworkOrder(int number) {
byte[] orderBytes = new byte[4];
orderBytes[3] = (byte) (number & 0xFF);
orderBytes[2] = (byte) (number >> 8 & 0xFF);
orderBytes[1] = (byte) (number >> 16 & 0xFF);
orderBytes[0] = (byte) (number >> 24 & 0xFF);
return orderBytes;
}
/**
* 4个字节的网络字节序bytes数组还原成一个数字
*
* @param bytesInNetworkOrder
*/
private int bytesNetworkOrder2Number(byte[] bytesInNetworkOrder) {
int sourceNumber = 0;
for (int i = 0; i < 4; i++) {
sourceNumber <<= 8;
sourceNumber |= bytesInNetworkOrder[i] & 0xff;
}
return sourceNumber;
}
/**
* 随机生成16位字符串
*
* @return
*/
private String genRandomStr() {
String base = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
Random random = new Random();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < 16; i++) {
int number = random.nextInt(base.length());
sb.append(base.charAt(number));
}
return sb.toString();
}
/**
* 生成xml消息
*
* @param encrypt 加密后的消息密文
* @param signature 安全签名
* @param timestamp 时间戳
* @param nonce 随机字符串
* @return 生成的xml字符串
*/
private String generateXml(String encrypt, String signature, String timestamp, String nonce) {
String format =
"<xml>\n"
+ "<Encrypt><![CDATA[%1$s]]></Encrypt>\n"
+ "<MsgSignature><![CDATA[%2$s]]></MsgSignature>\n"
+ "<TimeStamp>%3$s</TimeStamp>\n"
+ "<Nonce><![CDATA[%4$s]]></Nonce>\n"
+ "</xml>";
return String.format(format, encrypt, signature, timestamp, nonce);
}
static String extractEncryptPart(String xml) {
try {
DocumentBuilder db = builderLocal.get();
Document document = db.parse(new InputSource(new StringReader(xml)));
Element root = document.getDocumentElement();
return root.getElementsByTagName("Encrypt").item(0).getTextContent();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}