1 files changed, 69 insertions, 0 deletions
diff --git a/security/AsymmetricFingerprintDialog/Application/src/main/java/com/example/android/asymmetricfingerprintdialog/server/StoreBackendImpl.java b/security/AsymmetricFingerprintDialog/Application/src/main/java/com/example/android/asymmetricfingerprintdialog/server/StoreBackendImpl.java
new file mode 100644
index 00000000..8bf48d89
--- /dev/null
+++ b/security/AsymmetricFingerprintDialog/Application/src/main/java/com/example/android/asymmetricfingerprintdialog/server/StoreBackendImpl.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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 com.example.android.asymmetricfingerprintdialog.server;
+
+
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.security.PublicKey;
+import java.security.Signature;
+import java.security.SignatureException;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * A fake backend implementation of {@link StoreBackend}.
+ */
+public class StoreBackendImpl implements StoreBackend {
+
+    private final Map<String, PublicKey> mPublicKeys = new HashMap<>();
+
+    @Override
+    public boolean verify(Transaction transaction, byte[] transactionSignature) {
+        try {
+            PublicKey publicKey = mPublicKeys.get(transaction.getUserId());
+            Signature verificationFunction = Signature.getInstance("SHA256withECDSA");
+            verificationFunction.initVerify(publicKey);
+            verificationFunction.update(transaction.toByteArray());
+            if (verificationFunction.verify(transactionSignature)) {
+                // Transaction is verified with the public key associated with the user
+                // Do some post purchase processing in the server
+                return true;
+            }
+        } catch (NoSuchAlgorithmException | InvalidKeyException | SignatureException e) {
+            // In a real world, better to send some error message to the user
+        }
+        return false;
+    }
+
+    @Override
+    public boolean verify(Transaction transaction, String password) {
+        // As this is just a sample, we always assume that the password is right.
+        return true;
+    }
+
+    @Override
+    public boolean enroll(String userId, String password, PublicKey publicKey) {
+        if (publicKey != null) {
+            mPublicKeys.put(userId, publicKey);
+        }
+        // We just ignore the provided password here, but in real life, it is registered to the
+        // backend.
+        return true;
+    }
+
+}