Configuring Android for HTTPS Communication

You are not required to perform any additional steps to configure the Android server as it is preconfigured in WSO2 IoTS. This section provides information on how you can make the Android agent production ready.

Follow the instructions given below to configure and build the Android client application:

1. Get a GIT clone of the Android Agent application from GitHub.

2. Update the Android Software Development Kit with the following:

   • SDK Versions 23 and 16. 

   • Build Tools Version 22.0.1.

   • Install or update Android Support Library.

   • Install or update Google Play Services.

   • Install Google USB Driver, if you are on a Windows platform.

3. By default, the Android agent communicates with the server through HTTP. For production, this needs to be changed to https, by configuring the following parameters in the Java class named Constants.java, which is in the org.wso2.emm.agent.utils package: SERVER_PORT and SERVER_PROTOCOL.

   For more information see below:

    Generating a BKS File

   The Android agent must have the CA certificate inside the application when configuring the Secure Sockets Layer (SSL). The CA certificate is stored in a BKS (bouncycastle) file. Follow the steps given below to create and generate a BKS file: 

   • Prerequisites
   • Step 1: Creating a BKS file
   • Step 2: Generating a BKS file

   Prerequisites 

   • OpenSSL version 3.0.0.

     For more information, see how to download and install OpenSSL.

   • Set up the required environment variables when running on Windows.

      For more information, see setting paths on Windows.

   • The bcprov-jdk16-1.46.jar file.

     Download the bcprov-jdk16-1.46.jar file from the maven repository.

   • Clone the  cdmf-agent-android  GIT repository. This will be referred to as <ANDROID_AGENT>.

     git clone --branch v{ANDROID_AGENT_VERSION} https://github.com/wso2/cdmf-agent-android.git

      Click here to know the WSO2 IoT Server agent versions.

     This section provides information on the API and device agent versions that are compatible with each release of the WSO2 IoT Server. 

     IoT Server version	API version	Android agent version	iOS agent version
     3.0.0	1.0.0	2.0.0	2.0.0
     3.1.0	1.0.0	3.1.27	2.0.1
     3.2.0	1.0.0	3.1.31

   Step 1: Creating a BKS file

   If you configured IoTS for iOS, or if you have changed the IP of WSO2 IoT Server using the change-ip script, you can skip this step and move to Step 2 by using the already generated and imported Certificate Authority (CA), Registration Authority (RA), and SSL certificate files.

   1. Navigate to the openssl.cnf file of the OpenSSL installation. 

   2. Make a copy of the openssl.cnf file, move it to another location, and configure the file to generate version 3 certificates as shown below:

      [ v3_req ] 
      # Extensions to add to a certificate request 
      basicConstraints=CA:TRUE 
      keyUsage = Digital Signature, Key Encipherment 
      
      [ v3_ca ] 
      # Extensions for a typical CA 
      # PKIX recommendation. 
      subjectKeyIdentifier=hash 
      authorityKeyIdentifier=keyid:always,issuer 
      # This is what PKIX recommends but some broken software chokes on critical 
      # extensions. 
      basicConstraints = critical,CA:true 
      # So we do this instead. 
      #basicConstraints = CA:true 
      # Key usage: this is typical for a CA certificate. However since it will 
      # prevent it being used as an test self-signed certificate it is best 
      # left out by default. 
      keyUsage = Digital Signature, Certificate Sign, CRL Sign

   3. In the location where you modified and saved the openssl.cnf file, run the following commands to generate a self-signed Certificate Authority (CA) certificate (version 3) and convert the certificate to the .pem format:

      1. openssl genrsa -out <CA PRIVATE KEY> 4096
         For example: openssl genrsa -out ca_private.key 4096
      2. openssl req -new -key <CA PRIVATE KEY> -out <CA CSR>
         For example: openssl req -new -key ca_private.key -out ca.csr
      3. openssl x509 -req -days <DAYS> -in <CA CSR> -signkey <CA PRIVATE KEY> -out <CA CRT> -extensions v3_ca -extfile <PATH-TO-MODIFIED-openssl.cnf-FILE> 
         For example: openssl x509 -req -days 365 -in ca.csr -signkey ca_private.key -out ca.crt -extensions v3_ca -extfile ./openssl.cnf
      4. openssl rsa -in <CA PRIVATE KEY> -text > <CA PRIVATE PEM>
         For example:  openssl rsa -in ca_private.key -text > ca_private.pem
      5. openssl x509 -in <CA CRT> -out <CA CERT PEM>
         For example: openssl x509 -in ca.crt -out ca_cert.pem

   4. In the same location, run the following commands to generate a Registration Authority (RA) certificate (version 3), sign it with the CA, and convert the certificate to the .pem format. 

      1. openssl genrsa -out <RA PRIVATE KEY> 4096 
         For example:  openssl genrsa -out ra_private.key 4096

      2. openssl req -new -key <RA PRIVATE KEY> -out <RA CSR> 
         For example: openssl req -new -key ra_private.key -out ra.csr
      3. openssl x509 -req -days <DAYS> -in <RA CSR> -CA <CA CRT> -CAkey <CA PRIVATE KEY> -set_serial <SERIAL NO> -out <RA CRT> -extensions v3_req -extfile <PATH-TO-MODIFIED- openssl.cnf-FILE > 
         For example: openssl x509 -req -days 365 -in ra.csr -CA ca.crt -CAkey ca_private.key -set_serial 02 -out ra.crt -extensions v3_req -extfile ./openssl.cnf
      4. openssl rsa -in <CA PRIVATE KEY> -text > <RA PRIVATE PEM> 
         For example: openssl rsa -in ra_private.key -text > ra_private.pem
      5. openssl x509 -in <RA CRT> -out <RA CERT PEM> 
         For example: openssl x509 -in ra.crt -out ra_cert.pem

   5. Generate the SSL certificate (version 3) based on your domain/IP address:

      You must add your IP address/domain as the Common Name. Otherwise, provisioning will fail. 

      1. Generate an RSA key.
         openssl genrsa -out <RSA_key>.key 4096 
         For example:
         openssl genrsa -out ia.key 4096
      2. Generate a CSR file.
         openssl req -new -key <RSA_key>.key -out <CSR>.csr 
         For example:
         openssl req -new -key ia.key -out ia.csr 
         Enter your server IP address/domain name (e.g., 192.168.1.157) as the Common Name else provisioning will fail.
      3. Generate the SSL certificate.
         openssl x509 -req -days 730 -in <CSR>.csr -CA ca_cert.pem -CAkey ca_private.pem -set_serial <serial number> -out ia.crt 
         For example:  
         openssl x509 -req -days 730 -in ia.csr -CA ca_cert.pem -CAkey ca_private.pem -set_serial 044324343 -out ia.crt

   6. Export the SSL, CA, and RA files as PKCS12 files with an alias.

      1. Export the SSL file as a PKCS12 file with "wso2carbon" as the alias. 
         openssl pkcs12 -export -out <KEYSTORE>.p12 -inkey <RSA_key>.key -in ia.crt -CAfile ca_cert.pem -name "<alias>" 
         For example:
         openssl pkcs12 -export -out KEYSTORE.p12 -inkey ia.key -in ia.crt -CAfile ca_cert.pem -name "wso2carbon"

      2. Export the CA file as a PKCS12 file with an alias.
         openssl pkcs12 -export -out <CA>.p12 -inkey <CA private key>.pem -in <CA Cert>.pem -name "<alias>" 
         For example: 
         openssl pkcs12 -export -out ca.p12 -inkey ca_private.pem -in ca_cert.pem -name "cacert" 
         In the above example, cacert has been used as the CA alias. 
      3. Export the RA file as a PKCS12 file with an alias.
         openssl pkcs12 -export -out <RA>.p12 -inkey <RA private key>.pem -in <RA Cert>.pem -chain -CAfile <CA cert>.pem -name "<alias>" 
         For example: 
         openssl pkcs12 -export -out ra.p12 -inkey ra_private.pem -in ra_cert.pem -chain -CAfile ca_cert.pem -name "racert" 
         In the above example, racert has been used as the RA alias. 
   7. Copy the three P12 files to the <IOTS_HOME>/core/repository/resources/security directory.
   8. Import the generated P12 files as follows:
      

      1. Import the generated <KEYSTORE>.p12 file into the wso2carbon.jks and client-truststore.jks in the <IoT_HOME>/core/repository/resources/security directory.
         keytool -importkeystore -srckeystore <KEYSTORE>.p12 -srcstoretype PKCS12 -destkeystore <wso2carbon.jks/client-truststore.jks>

         When prompted, enter the key store password and key store key password as wso2carbon.

         For example: 
         keytool -importkeystore -srckeystore KEYSTORE.p12 -srcstoretype PKCS12 -destkeystore wso2carbon.jks 
keytool -importkeystore -srckeystore KEYSTORE.p12 -srcstoretype PKCS12 -destkeystore client-truststore.jks

      2. Import the generated <CA>.p12 and <RA>.p12 files into the wso2certs.jks file, which is in the <IoT_HOME>/core/repository/resources/security directory.
         keytool -importkeystore -srckeystore <CA/RA>.p12 -srcstoretype PKCS12 -destkeystore wso2certs.jks 
         
         For example:
         keytool -importkeystore -srckeystore ca.p12 -srcstoretype PKCS12 -destkeystore wso2certs.jks 
         Enter the keystore password as wso2carbon and keystore key password as cacert.

         keytool -importkeystore -srckeystore ra.p12 -srcstoretype PKCS12 -destkeystore wso2certs.jks 
         Enter the keystore password as  wso2carbon and keystore key password as racert.

         Troubleshooting

         Why does the following error occur: " keytool error: java.io.IOException: Invalid keystore format"?

         If you enter the wrong private key password when importing the <CA>.p12 or <RA>.p12 files, the wso2certs.jks file will get corrupted and the above error message will appear.

         In such a situation, delete the wso2certs.jks file and execute the following command to import the generated <CA>.p12 and <RA>.p12 files into the wso2certs.jks file again.
         keytool -importkeystore -srckeystore <CA/RA>.p12 -srcstoretype PKCS12 -destkeystore wso2certs.jks
         
         When the above command is executed, IoTS will automatically create a new wso2certs.jks file with the imported file.

   Step 2: Generating a BKS file

   Follow all the steps given under step 1 before generating the BKS file to avoid errors.

   1. Generate the BKS file:

      Make sure to generate the BKS file into the same folder that has the bcprov-jdk16-1.46.jar file before running the command given below. Else, you get the error given below:

      keytool error: java.lang.ClassNotFoundException: org.bouncycastle.jce.provider.BouncyCastleProvider
      java.lang.ClassNotFoundException: org.bouncycastle.jce.provider.BouncyCastleProvider
      	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
      	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
      	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
      	at sun.security.tools.keytool.Main.doCommands(Main.java:673)
      	at sun.security.tools.keytool.Main.run(Main.java:343)
      	at sun.security.tools.keytool.Main.main(Main.java:336)

      If you are using an SSL certificate by a trusted authority such as GoDaddy, the cert.crt defined in the command should be the interim certificate.  

      Example:

      keytool -noprompt -import -v -trustcacerts -alias godaddy -file cert.crt -keystore truststore.bks -storetype BKS -providerclass org.bouncycastle.jce.provider.BouncyCastleProvider -providerpath bcprov-jdk16-1.46.jar -storepass 'wso2carbon'

   2. Optionally, view the list of certificates in the BKS form using the following command:

      keytool -list -v -keystore "truststore.bks" -provider org.bouncycastle.jce.provider.BouncyCastleProvider -providerpath "bcprov-jdk16-1.46.jar" -storetype BKS -storepass "wso2carbon"

   3. Copy the generated truststore.bks file to the <ANDROID_AGENT>/client/iDPProxy/src/main/res/raw directory and replace the original file. 
   4. Navigate to the <ANDROID_AGENT>/client/client/src/main/java/org/wso2/iot/agent/utils/Constants.java file, and configure the following:
      • Provide the HTTPS_HOST_IP as the value for the API_SERVER_PORT parameter.
        Example: 9443.
      • Change the SERVER_PROTOCOL to https://.

   5. Configure the following files to get SSL to work on the Android agent:

      Configure the build release you want to compile to get the customized agent. For example, you can build the release, debug, staging or standalone build releases to meet your requirement.

      1. Configure the SERVER_PROTOCOL property to https in the client/iDPProxy/build.gradle file.

         buildConfigField "String", "SERVER_PROTOCOL", "\"https://\""

      2. Configure the DEFAULT_HOST property with the server URL in the client/client/build.gradle file.
         Example:

         buildConfigField "String", "DEFAULT_HOST", "\"https://10.10.10.192:8243\""

         After this configuration, the Android agent skips the following server URL entering screen during enrollment. 

   6. Navigate to the <ANDROID_AGENT>/client/iDPProxy/src/main/java/org/wso2/iot/agent/proxy/utils/Constants.java file, and provide the BKS file password as the value for the TRUSTSTORE_PASSWORD parameter.

4. The Android agent can't be built via the usual android developer SDK, as it requires access to developer restricted APIs. Therefore, you need to replace the existing android.jar file that is in the <SDK_LOCATION>/platforms/android-<COMPILE_SDK_VERSION> directory with the explicitly built android.jar file that has access to the restricted APIs. 
   You can get the new jar file using one of the following methods:

   • Download the Android Open Source Project (AOSP) and build the source code to get the jar file for the required SDK level.

   • Use a pre-built jar file from a third party developer. You can find it here: https://github.com/anggrayudi/android-hidden-api.

5. Import the project on Android Studio, clean and build the project.

6. Run the project on a device.

   The .apk file can be found in the <IoT_HOME>/core/repository/deployment/server/jaggeryapps/android-web-agent/app/pages/mdm.page.enrollments.android.download-agent/public/asset directory.

What's next

• Configure the Android Platform settings. For more information, see Android Platform Configurations.