In-App purchasing demo | Qt 6.4

- Qt 6.4
- In-App purchasing demo
- Qt 6.4.2 Reference Documentation

# In-App purchasing demo

     /* Copyright (c) 2012 Google Inc.
      * Copyright (c) 2015 The Qt Company Ltd.
      *
      * Licensed under the Apache License, Version 2.0 (the "License");
      * you may not use this file except in compliance with the License.
      * You may obtain a copy of the License at
      *
      *     http://www.apache.org/licenses/LICENSE-2.0
      *
      * Unless required by applicable law or agreed to in writing, software
      * distributed under the License is distributed on an "AS IS" BASIS,
      * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      * See the License for the specific language governing permissions and
      * limitations under the License.
      */

     package org.qtproject.qt.android.purchasing;

     import android.text.TextUtils;
     import android.util.Log;

     import org.json.JSONException;
     import org.json.JSONObject;

     import java.security.InvalidKeyException;
     import java.security.KeyFactory;
     import java.security.NoSuchAlgorithmException;
     import java.security.PublicKey;
     import java.security.Signature;
     import java.security.SignatureException;
     import java.security.spec.InvalidKeySpecException;
     import java.security.spec.X509EncodedKeySpec;

     /**
      * Security-related methods. For a secure implementation, all of this code
      * should be implemented on a server that communicates with the
      * application on the device. For the sake of simplicity and clarity of this
      * example, this code is included here and is executed on the device. If you
      * must verify the purchases on the phone, you should obfuscate this code to
      * make it harder for an attacker to replace the code with stubs that treat all
      * purchases as verified.
      */
     public class Security {
         private static final String TAG = "IABUtil/Security";

         private static final String KEY_FACTORY_ALGORITHM = "RSA";
         private static final String SIGNATURE_ALGORITHM = "SHA1withRSA";

         /**
          * Verifies that the data was signed with the given signature, and returns
          * the verified purchase. The data is in JSON format and signed
          * with a private key. The data also contains the {@link PurchaseState}
          * and product ID of the purchase.
          * @param base64PublicKey the base64-encoded public key to use for verifying.
          * @param signedData the signed JSON string (signed, not encrypted)
          * @param signature the signature for the data, signed with the private key
          */
         public static boolean verifyPurchase(String base64PublicKey, String signedData, String signature) {
             if (signedData == null) {
                 Log.e(TAG, "data is null");
                 return false;
             }

             boolean verified = false;
             if (!TextUtils.isEmpty(signature)) {
                 PublicKey key = Security.generatePublicKey(base64PublicKey);
                 verified = Security.verify(key, signedData, signature);
                 if (!verified) {
                     Log.w(TAG, "signature does not match data.");
                     return false;
                 }
             }
             return true;
         }

         /**
          * Generates a PublicKey instance from a string containing the
          * Base64-encoded public key.
          *
          * @param encodedPublicKey Base64-encoded public key
          * @throws IllegalArgumentException if encodedPublicKey is invalid
          */
         public static PublicKey generatePublicKey(String encodedPublicKey) {
             try {
                 byte[] decodedKey = Base64.decode(encodedPublicKey);
                 KeyFactory keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM);
                 return keyFactory.generatePublic(new X509EncodedKeySpec(decodedKey));
             } catch (NoSuchAlgorithmException e) {
                 throw new RuntimeException(e);
             } catch (InvalidKeySpecException e) {
                 Log.e(TAG, "Invalid key specification.");
                 throw new IllegalArgumentException(e);
             } catch (Base64DecoderException e) {
                 Log.e(TAG, "Base64 decoding failed.");
                 throw new IllegalArgumentException(e);
             }
         }

         /**
          * Verifies that the signature from the server matches the computed
          * signature on the data.  Returns true if the data is correctly signed.
          *
          * @param publicKey public key associated with the developer account
          * @param signedData signed data from server
          * @param signature server signature
          * @return true if the data and signature match
          */
         public static boolean verify(PublicKey publicKey, String signedData, String signature) {
             Signature sig;
             try {
                 sig = Signature.getInstance(SIGNATURE_ALGORITHM);
                 sig.initVerify(publicKey);
                 sig.update(signedData.getBytes());
                 if (!sig.verify(Base64.decode(signature))) {
                     Log.e(TAG, "Signature verification failed.");
                     return false;
                 }
                 return true;
             } catch (NoSuchAlgorithmException e) {
                 Log.e(TAG, "NoSuchAlgorithmException.");
             } catch (InvalidKeyException e) {
                 Log.e(TAG, "Invalid key specification.");
             } catch (SignatureException e) {
                 Log.e(TAG, "Signature exception.");
             } catch (Base64DecoderException e) {
                 Log.e(TAG, "Base64 decoding failed.");
             }
             return false;
         }
     }