WXBizMsgCrypt.java

解密过程，如下：

/**

* 对密文进行解密.

* 

* @param text 需要解密的密文

* @return 解密得到的明文

* @throws AesException aes解密失败

*/

String decrypt(String text) throws AesException {

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(text);

// 解密

original = cipher.doFinal(encrypted);

} catch (Exception e) {

e.printStackTrace();

throw new AesException(AesException.DecryptAESError);

}

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 = recoverNetworkBytesOrder(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) {

e.printStackTrace();

throw new AesException(AesException.IllegalBuffer);

}

// appid不相同的情况

if (!from_appid.equals(appId)) {

throw new AesException(AesException.ValidateAppidError);

}

return xmlContent;

}

上面代码中，标红处解密出错，如下：

需要解密的内容如下：

<xml>

    <AppId><![CDATA[wx715ef430c8070462]]></AppId>

    <Encrypt><![CDATA[5NWqy2SBB3fPlQRkrHUDe2SnrQGpeCvI04jXc7WmGJQeuCoTlssyopMuCnX2tsrmfw+oEJUugOLV6RFT65dfyJ7PS3uGpH+WzFq+gJuSQYu40cQllKNHuV7tI+hnp7HfQrZ5a9aJUGNDgz4EJuimtkIVo+DaPgA/CfxRd1eDBtnvqcYzJ10f7lXImPa2RuSDvyxBiT3d6JzH3BSz8oMSw7ah8WEIp0B38X1WlTGk7UdP2RMcSO2GgCjP4kN593EQBR0g8lJPb04Xo4bDrdDEChGhhMxzi1Y7ywZxwvrm0oWyVdX6DTfAoh6X4+tQic/BoWjlrMaYC2GHwUJ83E1FQr6eEAsPezMfkGYln/GVlkuiMilozDueyT8KQkF/rCmx6T9SZLix7/eq/VJsDbwVcg3stgwLfhCUHnS+LUXNZ4tdlbr4xt/N/u8CzFOr+SlVeOCZ8xa7L7JeIH9rvO/93g==]]></Encrypt>

</xml>