MQTT 是一种轻量级的、灵活的物联网消息交换和数据传递协议，致力于为 IoT 开发人员实现灵活性与硬件/网络资源的平衡。为了确保通讯安全，通常使用 TLS/SSL 来进行通讯加密。
本文主要介绍如何通过 Android 与 MQTT 进行 TLS/SSL 单向认证和双向认证。
准备
本文使用 Eclipse Paho Android Service 和 BouncyCastle，添加依赖
dependencies {
implementation 'org.eclipse.paho:org.eclipse.paho.client.mqttv3:1.1.0'
implementation 'org.eclipse.paho:org.eclipse.paho.android.service:1.1.1'
implementation 'org.bouncycastle:bcpkix-jdk15on:1.59'
}
以下是 Android 连接 TLS/SSL 的核心代码部分
MqttConnectOptions options = new MqttConnectOptions();
SSLSocketFactory sslSocketFactory = ...
options.setSocketFactory(sslSocketFactory);
重点在于如何获取 SSLSocketFactory，下面对单向认证和双向认证分别进行说明。
单向认证
单向认证是指服务端认证客户端，以下是核心代码
public static SSLSocketFactory getSingleSocketFactory(InputStream caCrtFileInputStream) throws Exception {
Security.addProvider(new BouncyCastleProvider());
X509Certificate caCert = null;
BufferedInputStream bis = new BufferedInputStream(caCrtFileInputStream);
CertificateFactory cf = CertificateFactory.getInstance("X.509");
while (bis.available() > 0) {
caCert = (X509Certificate) cf.generateCertificate(bis);
}
KeyStore caKs = KeyStore.getInstance(KeyStore.getDefaultType());
caKs.load(null, null);
caKs.setCertificateEntry("cert-certificate", caCert);
TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
tmf.init(caKs);
SSLContext sslContext = SSLContext.getInstance("TLSv1.2");
sslContext.init(null, tmf.getTrustManagers(), null);
return sslContext.getSocketFactory();
}
我们把 ca.crt 放到 res/raw 下，然后调用
try {
InputStream caCrtFileI = context.getResources().openRawResource(R.raw.ca);
options.setSocketFactory(getSingleSocketFactory(caCrtFile));
} catch (Exception e) {
e.printStackTrace();
}
双向认证
双向认证是指服务端和客户端相互认证，以下是关键代码
public static SSLSocketFactory getSocketFactory(InputStream caCrtFile, InputStream crtFile, InputStream keyFile,
String password) throws Exception {
Security.addProvider(new BouncyCastleProvider());
// load CA certificate
X509Certificate caCert = null;
BufferedInputStream bis = new BufferedInputStream(caCrtFile);
CertificateFactory cf = CertificateFactory.getInstance("X.509");
while (bis.available() > 0) {
caCert = (X509Certificate) cf.generateCertificate(bis);
}
// load client certificate
bis = new BufferedInputStream(crtFile);
X509Certificate cert = null;
while (bis.available() > 0) {
cert = (X509Certificate) cf.generateCertificate(bis);
}
// load client private cert
PEMParser pemParser = new PEMParser(new InputStreamReader(keyFile));
Object object = pemParser.readObject();
JcaPEMKeyConverter converter = new JcaPEMKeyConverter().setProvider("BC");
KeyPair key = converter.getKeyPair((PEMKeyPair) object);
KeyStore caKs = KeyStore.getInstance(KeyStore.getDefaultType());
caKs.load(null, null);
caKs.setCertificateEntry("cert-certificate", caCert);
TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
tmf.init(caKs);
KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
ks.load(null, null);
ks.setCertificateEntry("certificate", cert);
ks.setKeyEntry("private-cert", key.getPrivate(), password.toCharArray(),
new java.security.cert.Certificate[]{cert});
KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
kmf.init(ks, password.toCharArray());
SSLContext context = SSLContext.getInstance("TLSv1.2");
context.init(kmf.getKeyManagers(), tmf.getTrustManagers(), null);
return context.getSocketFactory();
}
我们需要准备好服务端证书，客户端证书和秘钥放到 res/raw 下，然后调用，注意密码设为空字符串
try {
InputStream caCrtFile = context.getResources().openRawResource(R.raw.ca);
InputStream crtFile = context.getResources().openRawResource(R.raw.cert);
InputStream keyFile = context.getResources().openRawResource(R.raw.key);
options.setSocketFactory(getSocketFactory(caCrtFile, crtFile, keyFile, ""));
} catch (Exception e) {
e.printStackTrace();
}
以上就是如何在 Android 上与 MQTT 进行 TLS/SSL 单向认证和双向认证。
版权声明： 本文为 EMQ 原创，转载请注明出处。
原文链接：https://www.emqx.io/cn/blog/android-mqtt-ssl-tls-authentication
