Make sure we only catch specific exceptions instead of catching them all

app/src/main/java/me/impy/aegis/crypto/CryptoUtils.java

@@ -27,7 +27,6 @@ import org.spongycastle.crypto.generators.SCrypt;
 
 public class CryptoUtils {
     public static final String CRYPTO_HASH = "SHA-256";
-    public static final byte CRYPTO_HASH_SIZE = 32;
 
     public static final String CRYPTO_CIPHER_RAW = "AES/ECB/NoPadding";
     public static final byte CRYPTO_KEY_SIZE = 32;
@@ -35,31 +34,36 @@ public class CryptoUtils {
     public static final String CRYPTO_CIPHER_AEAD = "AES/GCM/NoPadding";
     public static final byte CRYPTO_TAG_SIZE = 16;
     public static final byte CRYPTO_NONCE_SIZE = 12;
-    public static final byte CRYPTO_SALT_SIZE = 32;
 
     public static final int CRYPTO_SCRYPT_N = 1 << 15;
     public static final int CRYPTO_SCRYPT_r = 8;
     public static final int CRYPTO_SCRYPT_p = 1;
 
-    public static SecretKey deriveKey(char[] password, byte[] salt, int n, int r, int p) throws NoSuchAlgorithmException, InvalidKeySpecException {
+    public static SecretKey deriveKey(char[] password, byte[] salt, int n, int r, int p)
+            throws NoSuchAlgorithmException, InvalidKeySpecException {
         byte[] bytes = toBytes(password);
         byte[] keyBytes = SCrypt.generate(bytes, salt, n, r, p, CRYPTO_KEY_SIZE);
         return new SecretKeySpec(keyBytes, 0, keyBytes.length, "AES");
     }
 
-    public static Cipher createCipher(SecretKey key, int opmode) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException, InvalidKeyException {
+    public static Cipher createCipher(SecretKey key, int opmode)
+            throws NoSuchPaddingException, NoSuchAlgorithmException,
+            InvalidAlgorithmParameterException, InvalidKeyException {
         byte[] nonce = generateNonce();
         return createCipher(key, opmode, nonce);
     }
 
-    public static Cipher createCipher(SecretKey key, int opmode, byte[] nonce) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException, InvalidKeyException {
+    public static Cipher createCipher(SecretKey key, int opmode, byte[] nonce)
+            throws NoSuchPaddingException, NoSuchAlgorithmException,
+            InvalidAlgorithmParameterException, InvalidKeyException {
         IvParameterSpec spec = new IvParameterSpec(nonce);
         Cipher cipher = Cipher.getInstance(CRYPTO_CIPHER_AEAD);
         cipher.init(opmode, key, spec);
         return cipher;
     }
 
-    public static CryptResult encrypt(byte[] data, Cipher cipher) throws BadPaddingException, IllegalBlockSizeException {
+    public static CryptResult encrypt(byte[] data, Cipher cipher)
+            throws BadPaddingException, IllegalBlockSizeException {
         // split off the tag to store it separately
         byte[] result = cipher.doFinal(data);
         byte[] tag = Arrays.copyOfRange(result, result.length - CRYPTO_TAG_SIZE, result.length);
@@ -74,7 +78,8 @@ public class CryptoUtils {
         }};
     }
 
-    public static CryptResult decrypt(byte[] encrypted, Cipher cipher, CryptParameters params) throws IOException, BadPaddingException, IllegalBlockSizeException {
+    public static CryptResult decrypt(byte[] encrypted, Cipher cipher, CryptParameters params)
+            throws IOException, BadPaddingException, IllegalBlockSizeException {
         // append the tag to the ciphertext
         ByteArrayOutputStream stream = new ByteArrayOutputStream();
         stream.write(encrypted);
@@ -94,7 +99,7 @@ public class CryptoUtils {
         try {
             hash = MessageDigest.getInstance(CRYPTO_HASH);
         } catch (NoSuchAlgorithmException e) {
-            throw new UndeclaredThrowableException(e);
+            throw new AssertionError(e);
         }
 
         byte[] bytes = key.getEncoded();
@@ -102,10 +107,14 @@ public class CryptoUtils {
         return hash.digest();
     }
 
-    public static SecretKey generateKey() throws NoSuchAlgorithmException {
+    public static SecretKey generateKey() {
+        try {
             KeyGenerator generator = KeyGenerator.getInstance("AES");
             generator.init(CRYPTO_KEY_SIZE * 8);
             return generator.generateKey();
+        } catch (NoSuchAlgorithmException e) {
+            throw new AssertionError(e);
+        }
     }
 
     public static byte[] generateSalt() {

app/src/main/java/me/impy/aegis/crypto/KeyStoreHandle.java

@@ -7,10 +7,12 @@ import android.security.keystore.KeyPermanentlyInvalidatedException;
 import android.security.keystore.KeyProperties;
 
 import java.io.IOException;
+import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.KeyStore;
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
+import java.security.NoSuchProviderException;
 import java.security.UnrecoverableKeyException;
 import java.security.cert.CertificateException;
 
@@ -40,8 +42,12 @@ public class KeyStoreHandle {
         }
     }
 
-    public SecretKey generateKey(String id) throws Exception {
+    public SecretKey generateKey(String id) throws KeyStoreHandleException {
-        if (isSupported()) {
+        if (!isSupported()) {
+            throw new KeyStoreHandleException("Symmetric KeyStore keys are not supported in this version of Android");
+        }
+
+        try {
             KeyGenerator generator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, STORE_NAME);
             generator.init(new KeyGenParameterSpec.Builder(id,
                     KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
@@ -53,14 +59,23 @@ public class KeyStoreHandle {
                     .build());
 
             return generator.generateKey();
-        } else {
+        } catch (NoSuchAlgorithmException | NoSuchProviderException | InvalidAlgorithmParameterException e) {
-            throw new Exception("Symmetric KeyStore keys are not supported in this version of Android");
+            throw new KeyStoreHandleException(e);
         }
     }
 
-    public SecretKey getKey(String id)
+    public SecretKey getKey(String id) throws KeyStoreHandleException {
-            throws UnrecoverableKeyException, NoSuchAlgorithmException, KeyStoreException {
+        SecretKey key;
-        SecretKey key = (SecretKey) _keyStore.getKey(id, null);
+
+        try {
+            key = (SecretKey) _keyStore.getKey(id, null);
+        } catch (UnrecoverableKeyException e) {
+            return null;
+        } catch (NoSuchAlgorithmException e) {
+            throw new RuntimeException(e);
+        } catch (KeyStoreException e) {
+            throw new KeyStoreHandleException(e);
+        }
 
         // try to initialize a dummy cipher
         // and see if KeyPermanentlyInvalidatedException is thrown
@@ -71,7 +86,7 @@ public class KeyStoreHandle {
                 cipher.init(Cipher.ENCRYPT_MODE, key);
             } catch (KeyPermanentlyInvalidatedException e) {
                 return null;
-            } catch (NoSuchPaddingException | InvalidKeyException e) {
+            } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException e) {
                 throw new RuntimeException(e);
             }
         }
@@ -79,8 +94,12 @@ public class KeyStoreHandle {
         return key;
     }
 
-    public void deleteKey(String id) throws KeyStoreException {
+    public void deleteKey(String id) throws KeyStoreHandleException {
+        try {
             _keyStore.deleteEntry(id);
+        } catch (KeyStoreException e) {
+            throw new KeyStoreHandleException(e);
+        }
     }
 
     public static boolean isSupported() {

app/src/main/java/me/impy/aegis/crypto/KeyStoreHandleException.java

@@ -4,4 +4,8 @@ public class KeyStoreHandleException extends Exception {
     public KeyStoreHandleException(Throwable cause) {
         super(cause);
     }
+
+    public KeyStoreHandleException(String message) {
+        super(message);
+    }
 }

app/src/main/java/me/impy/aegis/crypto/MasterKey.java

@@ -22,22 +22,36 @@ public class MasterKey implements Serializable {
         _key = key;
     }
 
-    public static MasterKey generate() throws NoSuchAlgorithmException {
+    public static MasterKey generate() {
         return new MasterKey(CryptoUtils.generateKey());
     }
 
-    public CryptResult encrypt(byte[] bytes)
+    public CryptResult encrypt(byte[] bytes) throws MasterKeyException {
-            throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, InvalidKeyException,
+        try {
-            NoSuchPaddingException, BadPaddingException, IllegalBlockSizeException {
             Cipher cipher = CryptoUtils.createCipher(_key, Cipher.ENCRYPT_MODE);
             return CryptoUtils.encrypt(bytes, cipher);
+        } catch (NoSuchPaddingException
+                | NoSuchAlgorithmException
+                | InvalidAlgorithmParameterException
+                | InvalidKeyException | BadPaddingException
+                | IllegalBlockSizeException e) {
+            throw new MasterKeyException(e);
+        }
     }
 
-    public CryptResult decrypt(byte[] bytes, CryptParameters params)
+    public CryptResult decrypt(byte[] bytes, CryptParameters params) throws MasterKeyException {
-            throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, InvalidKeyException,
+        try {
-            NoSuchPaddingException, BadPaddingException, IllegalBlockSizeException, IOException {
             Cipher cipher = CryptoUtils.createCipher(_key, Cipher.DECRYPT_MODE, params.Nonce);
             return CryptoUtils.decrypt(bytes, cipher, params);
+        } catch (NoSuchPaddingException
+                | NoSuchAlgorithmException
+                | InvalidAlgorithmParameterException
+                | InvalidKeyException
+                | BadPaddingException
+                | IOException
+                | IllegalBlockSizeException e) {
+            throw new MasterKeyException(e);
+        }
     }
 
     public byte[] getHash() {

app/src/main/java/me/impy/aegis/crypto/MasterKeyException.java

@@ -0,0 +1,7 @@
+package me.impy.aegis.crypto;
+
+public class MasterKeyException extends Exception {
+    public MasterKeyException(Throwable cause) {
+        super(cause);
+    }
+}

app/src/main/java/me/impy/aegis/crypto/otp/OTP.java

@@ -9,9 +9,10 @@ public class OTP {
     private OTP() {
     }
 
-    public static String generateOTP(KeyInfo info) throws InvalidKeyException, NoSuchAlgorithmException {
+    public static String generateOTP(KeyInfo info) throws OTPException {
         String otp;
 
+        try {
             switch (info.getType()) {
                 case "totp":
                     String time = Long.toHexString(System.currentTimeMillis() / 1000 / info.getPeriod());
@@ -21,7 +22,10 @@ public class OTP {
                     otp = HOTP.generateOTP(info.getSecret(), info.getCounter(), info.getDigits(), false, -1);
                     break;
                 default:
-                throw new RuntimeException();
+                    throw new RuntimeException("Bad OTP type");
+            }
+        } catch (NoSuchAlgorithmException | InvalidKeyException e) {
+            throw new OTPException(e);
         }
 
         return otp;

app/src/main/java/me/impy/aegis/crypto/otp/OTPException.java

@@ -0,0 +1,7 @@
+package me.impy.aegis.crypto.otp;
+
+public class OTPException extends Exception {
+    public OTPException(Throwable cause) {
+        super(cause);
+    }
+}

app/src/main/java/me/impy/aegis/db/Database.java

@@ -1,6 +1,7 @@
 package me.impy.aegis.db;
 
 import org.json.JSONArray;
+import org.json.JSONException;
 import org.json.JSONObject;
 
 import java.util.ArrayList;
@@ -8,12 +9,15 @@ import java.util.Collections;
 import java.util.List;
 import java.util.UUID;
 
+import me.impy.aegis.crypto.KeyInfoException;
+
 public class Database {
     private static final int VERSION = 1;
 
     private List<DatabaseEntry> _entries = new ArrayList<>();
 
-    public JSONObject serialize() throws Exception {
+    public JSONObject serialize() throws DatabaseException {
+        try {
             JSONArray array = new JSONArray();
             for (DatabaseEntry e : _entries) {
                 array.put(e.serialize());
@@ -23,13 +27,17 @@ public class Database {
             obj.put("version", VERSION);
             obj.put("entries", array);
             return obj;
+        } catch (JSONException e) {
+            throw new DatabaseException(e);
+        }
     }
 
-    public void deserialize(JSONObject obj) throws Exception {
+    public void deserialize(JSONObject obj) throws DatabaseException {
         // TODO: support different VERSION deserialization providers
+        try {
             int ver = obj.getInt("version");
             if (ver != VERSION) {
-            throw new Exception("Unsupported version");
+                throw new DatabaseException("Unsupported version");
             }
 
             JSONArray array = obj.getJSONArray("entries");
@@ -38,6 +46,9 @@ public class Database {
                 entry.deserialize(array.getJSONObject(i));
                 addKey(entry);
             }
+        } catch (JSONException | KeyInfoException e) {
+            throw new DatabaseException(e);
+        }
     }
 
     public void addKey(DatabaseEntry entry) {

app/src/main/java/me/impy/aegis/db/DatabaseException.java

@@ -0,0 +1,11 @@
+package me.impy.aegis.db;
+
+public class DatabaseException extends Exception {
+    public DatabaseException(Throwable cause) {
+        super(cause);
+    }
+
+    public DatabaseException(String message) {
+        super(message);
+    }
+}

app/src/main/java/me/impy/aegis/db/DatabaseFile.java

@@ -5,21 +5,16 @@ import android.util.Base64;
 import org.json.JSONException;
 import org.json.JSONObject;
 
-import java.io.IOException;
 import java.io.UnsupportedEncodingException;
-import java.security.InvalidAlgorithmParameterException;
-import java.security.InvalidKeyException;
-import java.security.NoSuchAlgorithmException;
-
-import javax.crypto.BadPaddingException;
-import javax.crypto.IllegalBlockSizeException;
-import javax.crypto.NoSuchPaddingException;
 
 import me.impy.aegis.crypto.CryptParameters;
 import me.impy.aegis.crypto.CryptResult;
 import me.impy.aegis.crypto.MasterKey;
+import me.impy.aegis.crypto.MasterKeyException;
 import me.impy.aegis.db.slots.SlotCollection;
+import me.impy.aegis.db.slots.SlotCollectionException;
 import me.impy.aegis.encoding.Hex;
+import me.impy.aegis.encoding.HexException;
 
 public class DatabaseFile {
     public static final byte VERSION = 1;
@@ -32,7 +27,8 @@ public class DatabaseFile {
         _slots = new SlotCollection();
     }
 
-    public byte[] serialize() throws JSONException, UnsupportedEncodingException {
+    public byte[] serialize() throws DatabaseFileException {
+        try {
             JSONObject cryptObj = null;
             if (_cryptParameters != null) {
                 cryptObj = new JSONObject();
@@ -53,13 +49,17 @@ public class DatabaseFile {
 
             String string = obj.toString(4);
             return string.getBytes("UTF-8");
+        } catch (SlotCollectionException | UnsupportedEncodingException | JSONException e) {
+            throw new DatabaseFileException(e);
+        }
     }
 
-    public void deserialize(byte[] data) throws Exception {
+    public void deserialize(byte[] data) throws DatabaseFileException {
+        try {
             JSONObject obj = new JSONObject(new String(data, "UTF-8"));
             JSONObject headerObj = obj.getJSONObject("header");
             if (obj.getInt("version") > VERSION) {
-            throw new Exception("unsupported version");
+                throw new DatabaseFileException("unsupported version");
             }
 
             JSONObject slotObj = headerObj.optJSONObject("slots");
@@ -80,6 +80,9 @@ public class DatabaseFile {
             } else {
                 _content = obj.getString("db");
             }
+        } catch (SlotCollectionException | UnsupportedEncodingException | JSONException | HexException e) {
+            throw new DatabaseFileException(e);
+        }
     }
 
     public boolean isEncrypted() {
@@ -90,13 +93,14 @@ public class DatabaseFile {
         return (JSONObject) _content;
     }
 
-    public JSONObject getContent(MasterKey key)
+    public JSONObject getContent(MasterKey key) throws DatabaseFileException {
-            throws NoSuchPaddingException, InvalidKeyException,
+        try {
-            NoSuchAlgorithmException, IllegalBlockSizeException,
-            BadPaddingException, InvalidAlgorithmParameterException, IOException, JSONException {
             byte[] bytes = Base64.decode((String) _content, Base64.NO_WRAP);
             CryptResult result = key.decrypt(bytes, _cryptParameters);
             return new JSONObject(new String(result.Data, "UTF-8"));
+        } catch (MasterKeyException | JSONException | UnsupportedEncodingException e) {
+            throw new DatabaseFileException(e);
+        }
     }
 
     public void setContent(JSONObject dbObj) {
@@ -104,16 +108,17 @@ public class DatabaseFile {
         _cryptParameters = null;
     }
 
-    public void setContent(JSONObject dbObj, MasterKey key)
+    public void setContent(JSONObject dbObj, MasterKey key) throws DatabaseFileException {
-            throws JSONException, UnsupportedEncodingException,
+        try {
-            NoSuchPaddingException, InvalidKeyException, NoSuchAlgorithmException,
-            IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException {
             String string = dbObj.toString(4);
             byte[] dbBytes = string.getBytes("UTF-8");
 
             CryptResult result = key.encrypt(dbBytes);
             _content = new String(Base64.encode(result.Data, Base64.NO_WRAP), "UTF-8");
             _cryptParameters = result.Parameters;
+        } catch (MasterKeyException | UnsupportedEncodingException | JSONException e) {
+            throw new DatabaseFileException(e);
+        }
     }
 
     public SlotCollection getSlots() {

app/src/main/java/me/impy/aegis/db/DatabaseFileException.java

@@ -0,0 +1,11 @@
+package me.impy.aegis.db;
+
+public class DatabaseFileException extends Exception {
+    public DatabaseFileException(Throwable cause) {
+        super(cause);
+    }
+
+    public DatabaseFileException(String message) {
+        super(message);
+    }
+}

app/src/main/java/me/impy/aegis/db/DatabaseManager.java

@@ -3,7 +3,6 @@ package me.impy.aegis.db;
 import android.content.Context;
 import android.os.Environment;
 
-import org.json.JSONException;
 import org.json.JSONObject;
 
 import java.io.DataInputStream;
@@ -35,9 +34,10 @@ public class DatabaseManager {
         return file.exists() && file.isFile();
     }
 
-    public void load() throws Exception {
+    public void load() throws DatabaseManagerException {
         assertState(true, false);
 
+        try {
             byte[] fileBytes;
             FileInputStream file = null;
 
@@ -63,24 +63,33 @@ public class DatabaseManager {
                 _db = new Database();
                 _db.deserialize(obj);
             }
+        } catch (IOException | DatabaseFileException | DatabaseException e) {
+            throw new DatabaseManagerException(e);
+        }
     }
 
-    public void lock() throws Exception {
+    public void lock() {
         assertState(false, true);
         // TODO: properly clear everything
         _key = null;
         _db = null;
     }
 
-    public void unlock(MasterKey key) throws Exception {
+    public void unlock(MasterKey key) throws DatabaseManagerException {
         assertState(true, true);
+
+        try {
             JSONObject obj = _file.getContent(key);
             _db = new Database();
             _db.deserialize(obj);
             _key = key;
+        } catch (DatabaseFileException | DatabaseException e) {
+            throw new DatabaseManagerException(e);
+        }
     }
 
-    public static void save(Context context, DatabaseFile file) throws IOException, JSONException {
+    public static void save(Context context, DatabaseFile file) throws DatabaseManagerException {
+        try {
             byte[] bytes = file.serialize();
 
             FileOutputStream stream = null;
@@ -93,10 +102,15 @@ public class DatabaseManager {
                     stream.close();
                 }
             }
+        } catch (IOException | DatabaseFileException e) {
+            throw new DatabaseManagerException(e);
+        }
     }
 
-    public void save() throws Exception {
+    public void save() throws DatabaseManagerException {
         assertState(false, true);
+
+        try {
             JSONObject obj = _db.serialize();
             if (_file.isEncrypted()) {
                 _file.setContent(obj, _key);
@@ -104,11 +118,15 @@ public class DatabaseManager {
                 _file.setContent(obj);
             }
             save(_context, _file);
+        } catch (DatabaseException | DatabaseFileException e) {
+            throw new DatabaseManagerException(e);
+        }
     }
 
-    public String export(boolean encrypt) throws Exception {
+    public String export(boolean encrypt) throws DatabaseManagerException {
         assertState(false, true);
 
+        try {
             DatabaseFile dbFile = new DatabaseFile();
             dbFile.setSlots(_file.getSlots());
             if (encrypt && getFile().isEncrypted()) {
@@ -138,34 +156,37 @@ public class DatabaseManager {
             }
 
             return file.getAbsolutePath();
+        } catch (DatabaseException | IOException | DatabaseFileException e) {
+            throw new DatabaseManagerException(e);
+        }
     }
 
-    public void addKey(DatabaseEntry entry) throws Exception {
+    public void addKey(DatabaseEntry entry) {
         assertState(false, true);
         _db.addKey(entry);
     }
 
-    public void removeKey(DatabaseEntry entry) throws Exception {
+    public void removeKey(DatabaseEntry entry) {
         assertState(false, true);
         _db.removeKey(entry);
     }
 
-    public void replaceKey(DatabaseEntry entry) throws Exception {
+    public void replaceKey(DatabaseEntry entry) {
         assertState(false, true);
         _db.replaceKey(entry);
     }
 
-    public void swapKeys(DatabaseEntry entry1, DatabaseEntry entry2) throws Exception {
+    public void swapKeys(DatabaseEntry entry1, DatabaseEntry entry2) {
         assertState(false, true);
         _db.swapKeys(entry1, entry2);
     }
 
-    public List<DatabaseEntry> getKeys() throws Exception {
+    public List<DatabaseEntry> getKeys() {
         assertState(false, true);
         return _db.getKeys();
     }
 
-    public MasterKey getMasterKey() throws Exception {
+    public MasterKey getMasterKey() {
         assertState(false, true);
         return _key;
     }
@@ -182,17 +203,17 @@ public class DatabaseManager {
         return _db == null;
     }
 
-    private void assertState(boolean locked, boolean loaded) throws Exception {
+    private void assertState(boolean locked, boolean loaded) {
         if (isLoaded() && !loaded) {
-            throw new Exception("database file has not been loaded yet");
+            throw new AssertionError("database file has not been loaded yet");
         } else if (!isLoaded() && loaded) {
-            throw new Exception("database file has is already been loaded");
+            throw new AssertionError("database file has is already been loaded");
         }
 
         if (isLocked() && !locked) {
-            throw new Exception("database file has not been unlocked yet");
+            throw new AssertionError("database file has not been unlocked yet");
         } else if (!isLocked() && locked) {
-            throw new Exception("database file has is already been unlocked");
+            throw new AssertionError("database file has is already been unlocked");
         }
     }
 }

app/src/main/java/me/impy/aegis/db/DatabaseManagerException.java

@@ -0,0 +1,7 @@
+package me.impy.aegis.db;
+
+public class DatabaseManagerException extends Exception {
+    public DatabaseManagerException(Throwable cause) {
+        super(cause);
+    }
+}

app/src/main/java/me/impy/aegis/db/slots/PasswordSlot.java

@@ -10,6 +10,7 @@ import javax.crypto.SecretKey;
 
 import me.impy.aegis.crypto.CryptoUtils;
 import me.impy.aegis.encoding.Hex;
+import me.impy.aegis.encoding.HexException;
 
 public class PasswordSlot extends RawSlot {
     private int _n;
@@ -22,35 +23,51 @@ public class PasswordSlot extends RawSlot {
     }
 
     @Override
-    public JSONObject serialize() throws JSONException {
+    public JSONObject serialize() throws SlotException {
+        try {
             JSONObject obj = super.serialize();
             obj.put("n", _n);
             obj.put("r", _r);
             obj.put("p", _p);
             obj.put("salt", Hex.toString(_salt));
             return obj;
+        } catch (JSONException e) {
+            throw new SlotException(e);
+        }
     }
 
     @Override
-    public void deserialize(JSONObject obj) throws Exception {
+    public void deserialize(JSONObject obj) throws SlotException {
+        try {
             super.deserialize(obj);
             _n = obj.getInt("n");
             _r = obj.getInt("r");
             _p = obj.getInt("p");
             _salt = Hex.toBytes(obj.getString("salt"));
+        } catch (JSONException | HexException e) {
+            throw new SlotException(e);
+        }
     }
 
-    public SecretKey deriveKey(char[] password, byte[] salt, int n, int r, int p) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    public SecretKey deriveKey(char[] password, byte[] salt, int n, int r, int p) throws SlotException {
+        try {
             SecretKey key = CryptoUtils.deriveKey(password, salt, n, r, p);
             _n = n;
             _r = r;
             _p = p;
             _salt = salt;
             return key;
+        } catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
+            throw new SlotException(e);
+        }
     }
 
-    public SecretKey deriveKey(char[] password) throws InvalidKeySpecException, NoSuchAlgorithmException {
+    public SecretKey deriveKey(char[] password) throws SlotException {
+        try {
             return CryptoUtils.deriveKey(password, _salt, _n, _r, _p);
+        } catch (InvalidKeySpecException | NoSuchAlgorithmException e) {
+            throw new SlotException(e);
+        }
     }
 
     @Override

app/src/main/java/me/impy/aegis/db/slots/Slot.java

@@ -20,6 +20,7 @@ import javax.crypto.spec.SecretKeySpec;
 import me.impy.aegis.crypto.CryptoUtils;
 import me.impy.aegis.crypto.MasterKey;
 import me.impy.aegis.encoding.Hex;
+import me.impy.aegis.encoding.HexException;
 
 public abstract class Slot implements Serializable {
     public final static byte TYPE_RAW = 0x00;
@@ -34,37 +35,54 @@ public abstract class Slot implements Serializable {
     }
 
     // getKey decrypts the encrypted master key in this slot with the given key and returns it.
-    public SecretKey getKey(Cipher cipher) throws BadPaddingException, IllegalBlockSizeException {
+    public SecretKey getKey(Cipher cipher) throws SlotException {
+        try {
             byte[] decryptedKeyBytes = cipher.doFinal(_encryptedMasterKey);
             return new SecretKeySpec(decryptedKeyBytes, CryptoUtils.CRYPTO_CIPHER_AEAD);
+        } catch (BadPaddingException | IllegalBlockSizeException e) {
+            throw new SlotException(e);
+        }
     }
 
     // setKey encrypts the given master key with the given key and stores the result in this slot.
-    public void setKey(MasterKey masterKey, Cipher cipher) throws BadPaddingException, IllegalBlockSizeException {
+    public void setKey(MasterKey masterKey, Cipher cipher) throws SlotException {
+        try {
             byte[] masterKeyBytes = masterKey.getBytes();
             _encryptedMasterKey = cipher.doFinal(masterKeyBytes);
+        } catch (BadPaddingException | IllegalBlockSizeException e) {
+            throw new SlotException(e);
+        }
     }
 
     // suppress the AES ECB warning
     // this is perfectly safe because we discard this cipher after passing CryptoUtils.CRYPTO_KEY_SIZE bytes through it
     @SuppressLint("getInstance")
-    public static Cipher createCipher(SecretKey key, int mode) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeyException {
+    public static Cipher createCipher(SecretKey key, int mode) throws SlotException {
+        try {
             Cipher cipher = Cipher.getInstance(CryptoUtils.CRYPTO_CIPHER_RAW);
             cipher.init(mode, key);
             return cipher;
+        } catch (NoSuchPaddingException | NoSuchAlgorithmException | InvalidKeyException e) {
+            throw new SlotException(e);
+        }
     }
 
-    public JSONObject serialize() throws JSONException {
+    public JSONObject serialize() throws SlotException {
+        try {
             JSONObject obj = new JSONObject();
             obj.put("type", getType());
             obj.put("uuid", _uuid.toString());
             obj.put("key", Hex.toString(_encryptedMasterKey));
             return obj;
+        } catch (JSONException e) {
+            throw new SlotException(e);
+        }
     }
 
-    public void deserialize(JSONObject obj) throws Exception {
+    public void deserialize(JSONObject obj) throws SlotException {
+        try {
             if (obj.getInt("type") != getType()) {
-            throw new Exception("slot type mismatch");
+                throw new SlotException("slot type mismatch");
             }
             // if there is no uuid, generate a new one
             if (!obj.has("uuid")) {
@@ -73,6 +91,9 @@ public abstract class Slot implements Serializable {
                 _uuid = UUID.fromString(obj.getString("uuid"));
             }
             _encryptedMasterKey = Hex.toBytes(obj.getString("key"));
+        } catch (JSONException | HexException e) {
+            throw new SlotException(e);
+        }
     }
 
     public abstract byte getType();

app/src/main/java/me/impy/aegis/db/slots/SlotCollection.java

@@ -10,17 +10,17 @@ import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 
-import javax.crypto.BadPaddingException;
 import javax.crypto.Cipher;
-import javax.crypto.IllegalBlockSizeException;
 import me.impy.aegis.crypto.MasterKey;
 import me.impy.aegis.encoding.Hex;
+import me.impy.aegis.encoding.HexException;
 
 public class SlotCollection implements Iterable<Slot>, Serializable {
     private List<Slot> _slots = new ArrayList<>();
     private byte[] _masterHash;
 
-    public static JSONObject serialize(SlotCollection slots) throws JSONException {
+    public static JSONObject serialize(SlotCollection slots) throws SlotCollectionException {
+        try {
             JSONObject obj = new JSONObject();
             obj.put("hash", Hex.toString(slots.getMasterHash()));
 
@@ -31,11 +31,15 @@ public class SlotCollection implements Iterable<Slot>, Serializable {
 
             obj.put("entries", entries);
             return obj;
+        } catch (SlotException | JSONException e) {
+            throw new SlotCollectionException(e);
+        }
     }
 
-    public static SlotCollection deserialize(JSONObject obj) throws Exception {
+    public static SlotCollection deserialize(JSONObject obj) throws SlotCollectionException {
         SlotCollection slots = new SlotCollection();
 
+        try {
             byte[] masterHash = Hex.toBytes(obj.getString("hash"));
             slots.setMasterHash(masterHash);
 
@@ -55,12 +59,15 @@ public class SlotCollection implements Iterable<Slot>, Serializable {
                         slot = new FingerprintSlot();
                         break;
                     default:
-                    throw new Exception("unrecognized slot type");
+                        throw new SlotException("unrecognized slot type");
                 }
 
                 slot.deserialize(slotObj);
                 slots.add(slot);
             }
+        } catch (SlotException | JSONException | HexException e) {
+            throw new SlotCollectionException(e);
+        }
 
         return slots;
     }
@@ -114,14 +121,12 @@ public class SlotCollection implements Iterable<Slot>, Serializable {
         return _slots.iterator();
     }
 
-    public void encrypt(Slot slot, MasterKey key, Cipher cipher)
+    public void encrypt(Slot slot, MasterKey key, Cipher cipher) throws SlotException {
-            throws BadPaddingException, IllegalBlockSizeException {
         slot.setKey(key, cipher);
         setMasterHash(key.getHash());
     }
 
-    public MasterKey decrypt(Slot slot, Cipher cipher)
+    public MasterKey decrypt(Slot slot, Cipher cipher) throws SlotException, SlotIntegrityException {
-            throws SlotIntegrityException, BadPaddingException, IllegalBlockSizeException {
         byte[] hash = getMasterHash();
         MasterKey key = new MasterKey(slot.getKey(cipher));
         if (!Arrays.equals(hash, key.getHash())) {

app/src/main/java/me/impy/aegis/db/slots/SlotCollectionException.java

@@ -0,0 +1,11 @@
+package me.impy.aegis.db.slots;
+
+public class SlotCollectionException extends Exception {
+    public SlotCollectionException(Throwable cause) {
+        super(cause);
+    }
+
+    public SlotCollectionException(String message) {
+        super(message);
+    }
+}

app/src/main/java/me/impy/aegis/db/slots/SlotException.java

@@ -0,0 +1,11 @@
+package me.impy.aegis.db.slots;
+
+public class SlotException extends Exception {
+    public SlotException(Throwable cause) {
+        super(cause);
+    }
+
+    public SlotException(String message) {
+        super(message);
+    }
+}

app/src/main/java/me/impy/aegis/importers/AegisImporter.java

@@ -4,7 +4,9 @@ import java.util.List;
 
 import me.impy.aegis.db.Database;
 import me.impy.aegis.db.DatabaseEntry;
+import me.impy.aegis.db.DatabaseException;
 import me.impy.aegis.db.DatabaseFile;
+import me.impy.aegis.db.DatabaseFileException;
 import me.impy.aegis.util.ByteInputStream;
 
 public class AegisImporter extends DatabaseImporter {
@@ -14,13 +16,17 @@ public class AegisImporter extends DatabaseImporter {
     }
 
     @Override
-    public List<DatabaseEntry> convert() throws Exception {
+    public List<DatabaseEntry> convert() throws DatabaseImporterException {
+        try {
             byte[] bytes = _stream.getBytes();
             DatabaseFile file = new DatabaseFile();
             file.deserialize(bytes);
             Database db = new Database();
             db.deserialize(file.getContent());
             return db.getKeys();
+        } catch (DatabaseFileException | DatabaseException e) {
+            throw new DatabaseImporterException(e);
+        }
     }
 
     @Override

app/src/main/java/me/impy/aegis/importers/DatabaseImporter.java

@@ -1,5 +1,6 @@
 package me.impy.aegis.importers;
 
+import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -19,14 +20,15 @@ public abstract class DatabaseImporter {
         _stream = stream;
     }
 
-    public abstract List<DatabaseEntry> convert() throws Exception;
+    public abstract List<DatabaseEntry> convert() throws DatabaseImporterException;
 
     public abstract String getName();
 
     public static DatabaseImporter create(ByteInputStream stream, Class<? extends DatabaseImporter> type) {
         try {
             return type.getConstructor(ByteInputStream.class).newInstance(stream);
-        } catch (Exception e) {
+        } catch (IllegalAccessException | InstantiationException
+                | NoSuchMethodException | InvocationTargetException e) {
             throw new RuntimeException(e);
         }
     }

app/src/main/java/me/impy/aegis/importers/DatabaseImporterException.java

@@ -0,0 +1,7 @@
+package me.impy.aegis.importers;
+
+public class DatabaseImporterException extends Exception {
+    public DatabaseImporterException(Throwable cause) {
+        super(cause);
+    }
+}

app/src/main/java/me/impy/aegis/importers/FreeOTPImporter.java

@@ -28,12 +28,16 @@ public class FreeOTPImporter extends DatabaseImporter {
     }
 
     @Override
-    public List<DatabaseEntry> convert() throws Exception {
+    public List<DatabaseEntry> convert() throws DatabaseImporterException {
+        try {
             XmlPullParser parser = Xml.newPullParser();
             parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
             parser.setInput(_stream, null);
             parser.nextTag();
             return parse(parser);
+        } catch (KeyInfoException | XmlPullParserException | JSONException | IOException e) {
+            throw new DatabaseImporterException(e);
+        }
     }
 
     @Override

app/src/main/java/me/impy/aegis/ui/AuthActivity.java

@@ -21,11 +21,13 @@ import javax.crypto.SecretKey;
 
 import me.impy.aegis.R;
 import me.impy.aegis.crypto.KeyStoreHandle;
+import me.impy.aegis.crypto.KeyStoreHandleException;
 import me.impy.aegis.crypto.MasterKey;
 import me.impy.aegis.db.slots.FingerprintSlot;
 import me.impy.aegis.db.slots.PasswordSlot;
 import me.impy.aegis.db.slots.Slot;
 import me.impy.aegis.db.slots.SlotCollection;
+import me.impy.aegis.db.slots.SlotException;
 import me.impy.aegis.helpers.FingerprintHelper;
 import me.impy.aegis.helpers.FingerprintUiHelper;
 import me.impy.aegis.helpers.EditTextHelper;
@@ -80,7 +82,7 @@ public class AuthActivity extends AegisActivity implements FingerprintUiHelper.C
                         break;
                     }
                 }
-            } catch (Exception e) {
+            } catch (KeyStoreHandleException | SlotException e) {
                 throw new UndeclaredThrowableException(e);
             }
 

app/src/main/java/me/impy/aegis/ui/IntroActivity.java

@@ -18,6 +18,9 @@ import me.impy.aegis.AegisApplication;
 import me.impy.aegis.R;
 import me.impy.aegis.crypto.CryptResult;
 import me.impy.aegis.crypto.MasterKey;
+import me.impy.aegis.db.DatabaseException;
+import me.impy.aegis.db.DatabaseFileException;
+import me.impy.aegis.db.DatabaseManagerException;
 import me.impy.aegis.db.slots.FingerprintSlot;
 import me.impy.aegis.db.slots.PasswordSlot;
 import me.impy.aegis.db.slots.Slot;
@@ -25,6 +28,7 @@ import me.impy.aegis.db.slots.SlotCollection;
 import me.impy.aegis.db.Database;
 import me.impy.aegis.db.DatabaseFile;
 import me.impy.aegis.db.DatabaseManager;
+import me.impy.aegis.db.slots.SlotException;
 import me.impy.aegis.ui.slides.CustomAuthenticatedSlide;
 import me.impy.aegis.ui.slides.CustomAuthenticationSlide;
 import me.impy.aegis.ui.tasks.DerivationTask;
@@ -134,17 +138,11 @@ public class IntroActivity extends AppIntro implements DerivationTask.Callback {
         // generate the master key
         MasterKey masterKey = null;
         if (cryptType != CustomAuthenticationSlide.CRYPT_TYPE_NONE) {
-            try {
             masterKey = MasterKey.generate();
-            } catch (Exception e) {
-                setException(e);
-                return;
-            }
         }
 
         SlotCollection slots = _databaseFile.getSlots();
         if (cryptType != CustomAuthenticationSlide.CRYPT_TYPE_NONE) {
-            try {
             // encrypt the master key with a key derived from the user's password
             // and add it to the list of slots
             if (_passwordSlot == null || _passwordCipher == null) {
@@ -153,13 +151,9 @@ public class IntroActivity extends AppIntro implements DerivationTask.Callback {
             try {
                 slots.encrypt(_passwordSlot, masterKey, _passwordCipher);
                 slots.add(_passwordSlot);
-                } catch (Exception e) {
+            } catch (SlotException e) {
                 setException(e);
             }
-            } catch (Exception e) {
-                setException(e);
-                return;
-            }
         }
 
         if (cryptType == CustomAuthenticationSlide.CRYPT_TYPE_FINGER) {
@@ -170,7 +164,7 @@ public class IntroActivity extends AppIntro implements DerivationTask.Callback {
                 Cipher cipher = _authenticatedSlide.getFingerCipher();
                 slots.encrypt(slot, masterKey, cipher);
                 slots.add(slot);
-            } catch (Exception e) {
+            } catch (SlotException e) {
                 setException(e);
                 return;
             }
@@ -185,7 +179,7 @@ public class IntroActivity extends AppIntro implements DerivationTask.Callback {
                 _databaseFile.setContent(obj, masterKey);
             }
             DatabaseManager.save(getApplicationContext(), _databaseFile);
-        } catch (Exception e) {
+        } catch (DatabaseException | DatabaseManagerException | DatabaseFileException e) {
             setException(e);
             return;
         }
@@ -205,7 +199,7 @@ public class IntroActivity extends AppIntro implements DerivationTask.Callback {
         if (key != null) {
             try {
                 _passwordCipher = Slot.createCipher(key, Cipher.ENCRYPT_MODE);
-            } catch (Exception e) {
+            } catch (SlotException e) {
                 setException(e);
             }
         } else {

app/src/main/java/me/impy/aegis/ui/MainActivity.java

@@ -21,6 +21,8 @@ import android.widget.Toast;
 import com.getbase.floatingactionbutton.FloatingActionsMenu;
 
 import java.io.ByteArrayOutputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
 import java.io.InputStream;
 import java.lang.reflect.UndeclaredThrowableException;
 import java.util.List;
@@ -28,11 +30,13 @@ import java.util.List;
 import me.impy.aegis.AegisApplication;
 import me.impy.aegis.R;
 import me.impy.aegis.crypto.MasterKey;
+import me.impy.aegis.db.DatabaseManagerException;
 import me.impy.aegis.db.slots.SlotCollection;
 import me.impy.aegis.db.DatabaseEntry;
 import me.impy.aegis.db.DatabaseManager;
 import me.impy.aegis.helpers.PermissionHelper;
 import me.impy.aegis.importers.DatabaseImporter;
+import me.impy.aegis.importers.DatabaseImporterException;
 import me.impy.aegis.ui.views.KeyProfile;
 import me.impy.aegis.ui.views.KeyProfileView;
 import me.impy.aegis.util.ByteInputStream;
@@ -107,10 +111,10 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
                     if (_db.isLocked()) {
                         startAuthActivity();
                     }
-                } catch (Exception e) {
+                } catch (DatabaseManagerException e) {
                     e.printStackTrace();
                     Toast.makeText(this, "An error occurred while trying to deserialize the database", Toast.LENGTH_LONG).show();
-                    throw new UndeclaredThrowableException(e);
+                    finish();
                 }
             }
         }
@@ -243,14 +247,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
                 onExport();
                 break;
             case PreferencesActivity.ACTION_SLOTS:
-                MasterKey masterKey;
+                MasterKey masterKey = _db.getMasterKey();
-                try {
-                    masterKey = _db.getMasterKey();
-                } catch (Exception e) {
-                    e.printStackTrace();
-                    Toast.makeText(this, "An error occurred while trying to obtain the database key", Toast.LENGTH_SHORT).show();
-                    break;
-                }
                 Intent intent = new Intent(this, SlotManagerActivity.class);
                 intent.putExtra("masterKey", masterKey);
                 intent.putExtra("slots", _db.getFile().getSlots());
@@ -272,7 +269,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
                     String filename;
                     try {
                         filename = _db.export(checked[0]);
-                    } catch (Exception e) {
+                    } catch (DatabaseManagerException e) {
                         e.printStackTrace();
                         Toast.makeText(this, "An error occurred while trying to export the database", Toast.LENGTH_SHORT).show();
                         return;
@@ -314,8 +311,8 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
         try {
             try {
                 fileStream = getContentResolver().openInputStream(data.getData());
-            } catch (Exception e) {
+            } catch (FileNotFoundException e) {
-                Toast.makeText(this, "An error occurred while trying to open the file", Toast.LENGTH_SHORT).show();
+                Toast.makeText(this, "Error: File not found", Toast.LENGTH_SHORT).show();
                 return;
             }
 
@@ -328,7 +325,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
                     outStream.write(buf, 0, read);
                 }
                 stream = new ByteInputStream(outStream.toByteArray());
-            } catch (Exception e) {
+            } catch (IOException e) {
                 Toast.makeText(this, "An error occurred while trying to read the file", Toast.LENGTH_SHORT).show();
                 return;
             }
@@ -338,7 +335,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
                 try {
                     entries = converter.convert();
                     break;
-                } catch (Exception e) {
+                } catch (DatabaseImporterException e) {
                     stream.reset();
                 }
             }
@@ -355,7 +352,8 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
             if (fileStream != null) {
                 try {
                     fileStream.close();
-                } catch (Exception e) {
+                } catch (IOException e) {
+                    e.printStackTrace();
                 }
             }
         }
@@ -405,13 +403,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
             if (!data.getBooleanExtra("delete", false)) {
                 // this profile has been serialized/deserialized and is no longer the same instance it once was
                 // to deal with this, the replaceKey functions are used
-                try {
                 _db.replaceKey(profile.getEntry());
-                } catch (Exception e) {
-                    e.printStackTrace();
-                    Toast.makeText(this, "An error occurred while trying to update an entry", Toast.LENGTH_SHORT).show();
-                    return;
-                }
                 _keyProfileView.replaceKey(profile);
                 saveDatabase();
             } else {
@@ -431,14 +423,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
     private void addKey(KeyProfile profile) {
         DatabaseEntry entry = profile.getEntry();
         entry.setName(entry.getInfo().getAccountName());
-        try {
         _db.addKey(entry);
-        } catch (Exception e) {
-            e.printStackTrace();
-            Toast.makeText(this, "An error occurred while trying to add an entry", Toast.LENGTH_SHORT).show();
-            return;
-        }
-
         _keyProfileView.addKey(profile);
     }
 
@@ -455,7 +440,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
             if (_db.isLocked()) {
                 _db.unlock(key);
             }
-        } catch (Exception e) {
+        } catch (DatabaseManagerException e) {
             e.printStackTrace();
             Toast.makeText(this, "An error occurred while trying to load/decrypt the database", Toast.LENGTH_LONG).show();
             startAuthActivity();
@@ -469,7 +454,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
         MasterKey key = (MasterKey) intent.getSerializableExtra("key");
         try {
             _db.unlock(key);
-        } catch (Exception e) {
+        } catch (DatabaseManagerException e) {
             e.printStackTrace();
             Toast.makeText(this, "An error occurred while trying to decrypt the database", Toast.LENGTH_LONG).show();
             startAuthActivity();
@@ -564,13 +549,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
             .setTitle("Delete entry")
             .setMessage("Are you sure you want to delete this profile?")
             .setPositiveButton(android.R.string.yes, (dialog, which) -> {
-                try {
                 _db.removeKey(profile.getEntry());
-                } catch (Exception e) {
-                    e.printStackTrace();
-                    Toast.makeText(this, "An error occurred while trying to delete an entry", Toast.LENGTH_SHORT).show();
-                    return;
-                }
                 saveDatabase();
 
                 _keyProfileView.removeKey(profile);
@@ -597,12 +576,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
                 return true;
             case R.id.action_lock:
                 _keyProfileView.clearKeys();
-                try {
                 _db.lock();
-                } catch (Exception e) {
-                    e.printStackTrace();
-                    Toast.makeText(this, "An error occurred while trying to lock the database", Toast.LENGTH_LONG).show();
-                }
                 startAuthActivity();
                 return true;
             default:
@@ -619,7 +593,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
     private void saveDatabase() {
         try {
             _db.save();
-        } catch (Exception e) {
+        } catch (DatabaseManagerException e) {
             e.printStackTrace();
             Toast.makeText(this, "An error occurred while trying to save the database", Toast.LENGTH_LONG).show();
         }
@@ -628,15 +602,9 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
     private void loadKeyProfiles() {
         updateLockIcon();
 
-        try {
         for (DatabaseEntry entry : _db.getKeys()) {
             _keyProfileView.addKey(new KeyProfile(entry));
         }
-        } catch (Exception e) {
-            e.printStackTrace();
-            Toast.makeText(this, "An error occurred while trying to load database entries", Toast.LENGTH_SHORT).show();
-            return;
-        }
     }
 
     private void updateLockIcon() {
@@ -654,12 +622,7 @@ public class MainActivity extends AegisActivity implements KeyProfileView.Listen
 
     @Override
     public void onEntryMove(DatabaseEntry entry1, DatabaseEntry entry2) {
-        try {
         _db.swapKeys(entry1, entry2);
-        } catch (Exception e) {
-            e.printStackTrace();
-            throw new UndeclaredThrowableException(e);
-        }
     }
 
     @Override

app/src/main/java/me/impy/aegis/ui/ScannerActivity.java

@@ -1,6 +1,5 @@
 package me.impy.aegis.ui;
 
-import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
@@ -14,6 +13,7 @@ import java.util.Collections;
 import me.dm7.barcodescanner.core.IViewFinder;
 import me.dm7.barcodescanner.zxing.ZXingScannerView;
 import me.impy.aegis.crypto.KeyInfo;
+import me.impy.aegis.crypto.KeyInfoException;
 import me.impy.aegis.db.DatabaseEntry;
 import me.impy.aegis.helpers.SquareFinderView;
 import me.impy.aegis.ui.views.KeyProfile;
@@ -64,9 +64,9 @@ public class ScannerActivity extends AegisActivity implements ZXingScannerView.R
             Intent resultIntent = new Intent();
             resultIntent.putExtra("KeyProfile", profile);
 
-            setResult(Activity.RESULT_OK, resultIntent);
+            setResult(RESULT_OK, resultIntent);
             finish();
-        } catch (Exception e) {
+        } catch (KeyInfoException e) {
             Toast.makeText(this, "An error occurred while trying to parse the QR code contents", Toast.LENGTH_SHORT).show();
         }
 

app/src/main/java/me/impy/aegis/ui/SlotManagerActivity.java

@@ -21,6 +21,7 @@ import me.impy.aegis.db.slots.FingerprintSlot;
 import me.impy.aegis.db.slots.PasswordSlot;
 import me.impy.aegis.db.slots.Slot;
 import me.impy.aegis.db.slots.SlotCollection;
+import me.impy.aegis.db.slots.SlotException;
 import me.impy.aegis.helpers.FingerprintHelper;
 import me.impy.aegis.ui.dialogs.FingerprintDialogFragment;
 import me.impy.aegis.ui.dialogs.PasswordDialogFragment;
@@ -167,7 +168,7 @@ public class SlotManagerActivity extends AegisActivity implements SlotAdapter.Li
     public void onSlotResult(Slot slot, Cipher cipher) {
         try {
             _slots.encrypt(slot, _masterKey, cipher);
-        } catch (Exception e) {
+        } catch (SlotException e) {
             onException(e);
             return;
         }

app/src/main/java/me/impy/aegis/ui/dialogs/FingerprintDialogFragment.java

@@ -15,8 +15,10 @@ import javax.crypto.SecretKey;
 
 import me.impy.aegis.R;
 import me.impy.aegis.crypto.KeyStoreHandle;
+import me.impy.aegis.crypto.KeyStoreHandleException;
 import me.impy.aegis.db.slots.FingerprintSlot;
 import me.impy.aegis.db.slots.Slot;
+import me.impy.aegis.db.slots.SlotException;
 import me.impy.aegis.helpers.FingerprintHelper;
 import me.impy.aegis.helpers.FingerprintUiHelper;
 
@@ -38,7 +40,7 @@ public class FingerprintDialogFragment extends SlotDialogFragment implements Fin
             SecretKey key = new KeyStoreHandle().generateKey(_slot.getUUID().toString());
             _cipher = Slot.createCipher(key, Cipher.ENCRYPT_MODE);
             _helper = new FingerprintUiHelper(manager, imgFingerprint, textFingerprint, this);
-        } catch (Exception e) {
+        } catch (KeyStoreHandleException | SlotException e) {
             throw new RuntimeException(e);
         }
 

app/src/main/java/me/impy/aegis/ui/dialogs/PasswordDialogFragment.java

@@ -15,6 +15,7 @@ import javax.crypto.Cipher;
 import me.impy.aegis.R;
 import me.impy.aegis.db.slots.PasswordSlot;
 import me.impy.aegis.db.slots.Slot;
+import me.impy.aegis.db.slots.SlotException;
 import me.impy.aegis.helpers.EditTextHelper;
 import me.impy.aegis.ui.tasks.DerivationTask;
 
@@ -51,7 +52,7 @@ public class PasswordDialogFragment extends SlotDialogFragment {
                     Cipher cipher;
                     try {
                         cipher = Slot.createCipher(key, Cipher.ENCRYPT_MODE);
-                    } catch (Exception e) {
+                    } catch (SlotException e) {
                         getListener().onException(e);
                         dialog.cancel();
                         return;

app/src/main/java/me/impy/aegis/ui/slides/CustomAuthenticatedSlide.java

@@ -25,6 +25,7 @@ import javax.crypto.SecretKey;
 
 import me.impy.aegis.R;
 import me.impy.aegis.crypto.KeyStoreHandle;
+import me.impy.aegis.crypto.KeyStoreHandleException;
 import me.impy.aegis.db.slots.FingerprintSlot;
 import me.impy.aegis.db.slots.Slot;
 import me.impy.aegis.helpers.FingerprintUiHelper;
@@ -102,7 +103,7 @@ public class CustomAuthenticatedSlide extends Fragment implements FingerprintUiH
                         _fingerSlot = new FingerprintSlot();
                     }
                     key = _storeHandle.generateKey(_fingerSlot.getUUID().toString());
-                } catch (Exception e) {
+                } catch (KeyStoreHandleException e) {
                     throw new UndeclaredThrowableException(e);
                 }
 

app/src/main/java/me/impy/aegis/ui/tasks/DerivationTask.java

@@ -3,10 +3,14 @@ package me.impy.aegis.ui.tasks;
 import android.content.Context;
 import android.os.Process;
 
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+
 import javax.crypto.SecretKey;
 
 import me.impy.aegis.crypto.CryptoUtils;
 import me.impy.aegis.db.slots.PasswordSlot;
+import me.impy.aegis.db.slots.SlotException;
 
 public class DerivationTask extends ProgressDialogTask<DerivationTask.Params, SecretKey> {
     private Callback _cb;
@@ -23,9 +27,8 @@ public class DerivationTask extends ProgressDialogTask<DerivationTask.Params, Se
         DerivationTask.Params params = args[0];
         try {
             byte[] salt = CryptoUtils.generateSalt();
-            SecretKey key = params.Slot.deriveKey(params.Password, salt, CryptoUtils.CRYPTO_SCRYPT_N, CryptoUtils.CRYPTO_SCRYPT_r, CryptoUtils.CRYPTO_SCRYPT_p);
+            return params.Slot.deriveKey(params.Password, salt, CryptoUtils.CRYPTO_SCRYPT_N, CryptoUtils.CRYPTO_SCRYPT_r, CryptoUtils.CRYPTO_SCRYPT_p);
-            return key;
+        } catch (SlotException e) {
-        } catch (Exception e) {
             return null;
         }
     }

app/src/main/java/me/impy/aegis/ui/tasks/SlotCollectionTask.java

@@ -13,6 +13,7 @@ import me.impy.aegis.db.slots.FingerprintSlot;
 import me.impy.aegis.db.slots.PasswordSlot;
 import me.impy.aegis.db.slots.Slot;
 import me.impy.aegis.db.slots.SlotCollection;
+import me.impy.aegis.db.slots.SlotException;
 import me.impy.aegis.db.slots.SlotIntegrityException;
 
 public class SlotCollectionTask<T extends Slot> extends ProgressDialogTask<SlotCollectionTask.Params, MasterKey> {
@@ -59,7 +60,7 @@ public class SlotCollectionTask<T extends Slot> extends ProgressDialogTask<SlotC
             return masterKey;
         } catch (SlotIntegrityException e) {
             return null;
-        } catch (Exception e) {
+        } catch (SlotException e) {
             throw new UndeclaredThrowableException(e);
         }
     }

app/src/main/java/me/impy/aegis/ui/views/KeyProfile.java

@@ -6,6 +6,7 @@ import java.io.Serializable;
 import java.lang.reflect.UndeclaredThrowableException;
 
 import me.impy.aegis.crypto.otp.OTP;
+import me.impy.aegis.crypto.otp.OTPException;
 import me.impy.aegis.db.DatabaseEntry;
 import me.impy.aegis.helpers.TextDrawableHelper;
 
@@ -31,7 +32,7 @@ public class KeyProfile implements Serializable {
     public String refreshCode() {
         try {
             _code = OTP.generateOTP(_entry.getInfo());
-        } catch (Exception e) {
+        } catch (OTPException e) {
             throw new UndeclaredThrowableException(e);
         }
         return _code;