/**
* 对xml消息加密
*
* @param appId 应用ID
* @param encodingAesKey 加密密钥
* @param xmlContent 原始消息体
* @return aes加密后的消息体
* @throws WeixinException
*/
public static String aesEncrypt(String appId, String encodingAesKey, String xmlContent)
throws WeixinException {
byte[] randomBytes = StringUtil.getBytesUtf8(RandomUtil.generateString(32));
byte[] xmlBytes = StringUtil.getBytesUtf8(xmlContent);
int xmlLength = xmlBytes.length;
byte[] orderBytes = new byte[4];
orderBytes[3] = (byte) (xmlLength & 0xFF);
orderBytes[2] = (byte) (xmlLength >> 8 & 0xFF);
orderBytes[1] = (byte) (xmlLength >> 16 & 0xFF);
orderBytes[0] = (byte) (xmlLength >> 24 & 0xFF);
byte[] appidBytes = StringUtil.getBytesUtf8(appId);
int byteLength = randomBytes.length + xmlLength + orderBytes.length + appidBytes.length;
// ... + pad: 使用自定义的填充方式对明文进行补位填充
byte[] padBytes = PKCS7Encoder.encode(byteLength);
// random + endian + xml + appid + pad 获得最终的字节流
byte[] unencrypted = new byte[byteLength + padBytes.length];
byteLength = 0;
// src:源数组;srcPos:源数组要复制的起始位置;dest:目的数组;destPos:目的数组放置的起始位置;length:复制的长度
System.arraycopy(randomBytes, 0, unencrypted, byteLength, randomBytes.length);
byteLength += randomBytes.length;
System.arraycopy(orderBytes, 0, unencrypted, byteLength, orderBytes.length);
byteLength += orderBytes.length;
System.arraycopy(xmlBytes, 0, unencrypted, byteLength, xmlBytes.length);
byteLength += xmlBytes.length;
System.arraycopy(appidBytes, 0, unencrypted, byteLength, appidBytes.length);
byteLength += appidBytes.length;
System.arraycopy(padBytes, 0, unencrypted, byteLength, padBytes.length);
try {
byte[] aesKey = Base64.decodeBase64(encodingAesKey + "=");
// 设置加密模式为AES的CBC模式
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
SecretKeySpec keySpec = new SecretKeySpec(aesKey, Consts.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
return Base64.encodeBase64String(encrypted);
} catch (Exception e) {
throw new WeixinException("-40006", "AES加密失败:" + e.getMessage());
}
}
