switched to AES/CBC/PKCS5, poster updated

app/src/main/java/de/overview/wg/its/mispbump/MainActivity.java

@@ -21,11 +21,13 @@ import android.view.View;
 import android.widget.CheckBox;
 import android.widget.TextView;
 import de.overview.wg.its.mispbump.adapter.SyncedPartnerAdapter;
+import de.overview.wg.its.mispbump.auxiliary.AESSecurity;
 import de.overview.wg.its.mispbump.auxiliary.PreferenceManager;
 import de.overview.wg.its.mispbump.model.SyncedPartner;
 import de.overview.wg.its.mispbump.preferences.AppPreferenceActivity;
 import de.overview.wg.its.mispbump.preferences.AppPreferenceFragment;
 
+import java.security.PublicKey;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -80,6 +82,29 @@ public class MainActivity extends AppCompatActivity {
 	}
 
 
+	private void testAESSecurity() {
+
+	    String data = "This is the secret message";
+
+        AESSecurity aesA = AESSecurity.getInstance();
+        AESSecurity aesB = AESSecurity.getInstance();
+
+        PublicKey pubA = aesA.getPublicKey();
+        PublicKey pubB = aesB.getPublicKey();
+
+        aesA.setForeignPublicKey(pubB);
+        aesB.setForeignPublicKey(pubA);
+
+        emptyPartnerListView.setText("ORIGINAL: " + data + "\n");
+
+        String encrypted = aesA.encrypt(data);
+        emptyPartnerListView.append("ENCRYPTED BY A: " + encrypted + "\n");
+
+        String decrypted = aesB.decrypt(encrypted);
+        emptyPartnerListView.append("DECRYPTED BY B: " + decrypted);
+
+    }
+
 	private void initializeViews() {
 
 		Toolbar toolbar = findViewById(R.id.toolbar);
@@ -149,15 +174,8 @@ public class MainActivity extends AppCompatActivity {
 	}
 
 	private void refreshSyncedPartnerList() {
-//		syncedPartnerList = PreferenceManager.Instance(this).getSyncedPartnerList();
+	    // todo: uncomment
-
+        // syncedPartnerList = PreferenceManager.Instance(this).getSyncedPartnerList();
-		SyncedPartner sp = new SyncedPartner("Example Organisation 1", "https://www.organisationa1.de");
-        sp.generateTimeStamp();
-        syncedPartnerList.add(sp);
-
-        sp = new SyncedPartner("Example Organisation 2", "https://www.organisation2.de");
-        sp.generateTimeStamp();
-        syncedPartnerList.add(sp);
 
 		if (syncedPartnerList == null || syncedPartnerList.size() < 1) {
 			emptyPartnerListView.setVisibility(View.VISIBLE);

app/src/main/java/de/overview/wg/its/mispbump/auxiliary/AESSecurity.java

@@ -1,40 +1,51 @@
 package de.overview.wg.its.mispbump.auxiliary;
 
 import android.util.Base64;
+import android.util.Log;
 
 import javax.crypto.*;
+import javax.crypto.spec.IvParameterSpec;
 import javax.crypto.spec.SecretKeySpec;
 import java.security.*;
 import java.security.spec.InvalidKeySpecException;
 import java.security.spec.X509EncodedKeySpec;
+import java.util.Arrays;
 
 public class AESSecurity {
 
 	private static final String TAG = "MISP_LOGGING";
-	private static final String ALGORITHM = "AES";
+
+    private static final String ENCRYPT_ALGORITHM = "AES/CBC/PKCS5Padding";
+    private static final String KEY_PAIR_ALGORITHM = "EC";
+    private static final int KEY_SIZE = 521; // 224 | 256 | 384 | 521
+    private static final String KEY_AGREEMENT_ALGORITHM = "ECDH";
 
     private static AESSecurity instance;
 
 	private PublicKey publickey;
 	private KeyAgreement keyAgreement;
+
 	private byte[] sharedSecret;
+    private IvParameterSpec ivParameterSpec;
 
 	private AESSecurity() {
 		initialize();
 	}
 
+    /***
+     * Generates a public and a private key using an elliptic curve algorithm (256 bit)
+     * The private key is fed into the key agreement instance
+     */
 	private void initialize() {
-		KeyPairGenerator kpg = null;
 
 		try {
-			kpg = KeyPairGenerator.getInstance("EC");
+            KeyPairGenerator kpg = KeyPairGenerator.getInstance(KEY_PAIR_ALGORITHM);
-			kpg.initialize(256);
+			kpg.initialize(KEY_SIZE);
 
 			KeyPair kp = kpg.generateKeyPair();
-
 			publickey = kp.getPublic();
 
-			keyAgreement = KeyAgreement.getInstance("ECDH");
+			keyAgreement = KeyAgreement.getInstance(KEY_AGREEMENT_ALGORITHM);
 			keyAgreement.init(kp.getPrivate());
 
 		} catch (NoSuchAlgorithmException | InvalidKeyException e) {
@@ -42,10 +53,24 @@ public class AESSecurity {
 		}
 	}
 
+    /***
+     * Generates a shared secret with a given public key
+     * @param publickey
+     */
 	public void setForeignPublicKey(PublicKey publickey) {
+
 	    try {
+
 			keyAgreement.doPhase(publickey, true);
-			sharedSecret = keyAgreement.generateSecret();
+
+			byte[] tmpSharedSecret = keyAgreement.generateSecret();
+
+            sharedSecret = Arrays.copyOfRange(tmpSharedSecret, 0, 32);
+
+            byte[] inputVector = Arrays.copyOfRange(sharedSecret, 32, 48);
+
+            ivParameterSpec = new IvParameterSpec(inputVector);
+
         } catch (InvalidKeyException e) {
 			e.printStackTrace();
 		}
@@ -53,12 +78,17 @@ public class AESSecurity {
 
 	public String encrypt(String data) {
 		try {
+
 			Key key = generateKey();
-			Cipher c = Cipher.getInstance(ALGORITHM);
+			Cipher c = Cipher.getInstance(ENCRYPT_ALGORITHM);
-			c.init(Cipher.ENCRYPT_MODE, key);
+
+            try {
+                c.init(Cipher.ENCRYPT_MODE, key, ivParameterSpec);
+            } catch (InvalidAlgorithmParameterException e) {
+                e.printStackTrace();
+            }
 
             byte[] encVal = c.doFinal(data.getBytes());
-
 			return Base64.encodeToString(encVal, 0);
 
 		} catch (BadPaddingException | InvalidKeyException | NoSuchPaddingException | IllegalBlockSizeException | NoSuchAlgorithmException e) {
@@ -70,8 +100,14 @@ public class AESSecurity {
 	public String decrypt(String data) {
 		try {
 			Key key = generateKey();
-			Cipher c = Cipher.getInstance(ALGORITHM);
+
-			c.init(Cipher.DECRYPT_MODE, key);
+			Cipher c = Cipher.getInstance(ENCRYPT_ALGORITHM);
+
+            try {
+                c.init(Cipher.DECRYPT_MODE, key, ivParameterSpec);
+            } catch (InvalidAlgorithmParameterException e) {
+                e.printStackTrace();
+            }
 
             byte[] decoded = Base64.decode(data, 0);
 			byte[] decValue = c.doFinal(decoded);
@@ -87,21 +123,22 @@ public class AESSecurity {
 	}
 
 	private Key generateKey() {
-		return new SecretKeySpec(sharedSecret, ALGORITHM);
+
+		return new SecretKeySpec(sharedSecret, ENCRYPT_ALGORITHM);
+
 	}
 
 	public static String publicKeyToString(PublicKey key) {
 		return Base64.encodeToString(key.getEncoded(), Base64.DEFAULT);
 	}
+
 	public static PublicKey publicKeyFromString(String key) {
 
-		KeyFactory kf = null;
+        try {
 
             byte[] input = Base64.decode(key, Base64.DEFAULT);
+            return KeyFactory.getInstance("EC").generatePublic(new X509EncodedKeySpec(input));
 
-		try {
-			kf = KeyFactory.getInstance("EC"); // normal: DH
-			return kf.generatePublic(new X509EncodedKeySpec(input));
 		} catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
 			e.printStackTrace();
 		}
@@ -110,10 +147,15 @@ public class AESSecurity {
 	}
 
 	public static AESSecurity getInstance() {
-		if(instance == null) {
-			instance = new AESSecurity();
-		}
 
-		return instance;
+	    //todo: make singleton again
+
+//		if(instance == null) {
+//			instance = new AESSecurity();
+//		}
+//
+//		return instance;
+
+        return new AESSecurity();
 	}
 }