我阅读了很多解释如何解决此类异常的内容，但我仍然无法解决此问题。
我的目标是： 1.使用SecretKey加密字符串数据并将其存储到SQLite数据库中。 2.从SQLite数据库中读取数据并使用相同的SecretKey对其进行解密。
这是我的类加密和解密android应用程序中的数据（目标1和2的实现）。此代码提供异常 - javax.crypto.IllegalBlockSizeException：解密时最后一个块不完整
我该如何解决这个错误？任何消化都将受到赞赏..谢谢
public class Cryptography {
private String encryptedFileName = "Enc_File2.txt";
private static String algorithm = "AES";
private static final int outputKeyLength = 256;
static SecretKey yourKey = null;
SQLiteDatabase database;
DBHelper helper;
Context context;
//saveFile("Hello From CoderzHeaven testing :: Gaurav Wable");
//decodeFile();
public Cryptography (Context context) {
this.context = context;
helper = new DBHelper(context);
database = helper.getWritableDatabase();
}
public String encryptString(String data) {
char[] p = { 'p', 'a', 's', 's' };
//SecretKey yourKey = null;
byte[] keyBytes = null;
byte[] filesBytes = null;
try {
if(this.yourKey == null) {
Log.d("key", "instance null");
Cursor cursor = database.query("assmain", new String[]{"keyAvailability"}, null, null, null, null, null);
cursor.moveToFirst();
if(cursor.getInt(cursor.getColumnIndex("keyAvailability")) == 1) {
Log.d("key", "exists in DB");
keyBytes = cursor.getBlob(cursor.getColumnIndex("key"));
cursor.close();
filesBytes = encodeFile(keyBytes, data.getBytes());
} else {
Log.d("key", "generating");
this.yourKey = generateKey(p, generateSalt().toString().getBytes());
filesBytes = encodeFile(this.yourKey, data.getBytes());
}
} else {
Log.d("key", "instance exists");
//yourKey = this.yourKey;
filesBytes = encodeFile(yourKey, data.getBytes());
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return new String(filesBytes);
}
public String decryptString(String data) {
String str = null;
byte[] decodedData = null;
try {
Log.d("To decrypt", data);
if(this.yourKey == null) {
Log.d("key", "null");
Cursor cursor = database.query("assmain", new String[]{"keyAvailability"}, null, null, null, null, null);
cursor.moveToFirst();
if(cursor.getInt(cursor.getColumnIndex("keyAvailability")) == 1) {
Log.d("key", "exists in DB");
byte[] keyBytes = cursor.getBlob(cursor.getColumnIndex("key"));
cursor.close();
decodedData = decodeFile(keyBytes, data.getBytes());
} else {
Log.d("key", "Unavailable");
Toast.makeText(context, "Key Unavailable", Toast.LENGTH_SHORT).show();
}
} else {
Log.d("key", "instance exists");
decodedData = decodeFile(this.yourKey, data.getBytes());
}
decodedData = decodeFile(yourKey, data.getBytes());
str = new String(decodedData);
} catch (Exception e) {
e.printStackTrace();
}
return str;
}
public static SecretKey generateKey(char[] passphraseOrPin, byte[] salt)
throws NoSuchAlgorithmException, InvalidKeySpecException {
// Number of PBKDF2 hardening rounds to use. Larger values increase
// computation time. You should select a value that causes computation
// to take >100ms.
final int iterations = 1000;
// Generate a 256-bit key
//final int outputKeyLength = 256;
SecretKeyFactory secretKeyFactory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
KeySpec keySpec = new PBEKeySpec(passphraseOrPin, salt, iterations,
outputKeyLength);
yourKey = secretKeyFactory.generateSecret(keySpec);
return yourKey;
}
public static SecretKey generateSalt() throws NoSuchAlgorithmException {
// Generate a 256-bit key
//final int outputKeyLength = 256;
SecureRandom secureRandom = new SecureRandom();
// Do *not* seed secureRandom! Automatically seeded from system entropy.
KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
keyGenerator.init(outputKeyLength, secureRandom);
SecretKey key = keyGenerator.generateKey();
return key;
}
public static byte[] encodeFile(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] data = yourKey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(data, 0, data.length,
algorithm);
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(fileData);
return encrypted;
}
public static byte[] encodeFile(byte[] data, byte[] fileData)
throws Exception {
//byte[] data = yourKey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(data, 0, data.length,
algorithm);
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(fileData);
return encrypted;
}
public static byte[] decodeFile(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] data = yourKey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(data, 0, data.length,
algorithm);
//Cipher cipher = Cipher.getInstance(algorithm);
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(fileData);
return decrypted;
}
public static byte[] decodeFile(byte[] data, byte[] fileData)
throws Exception {
//byte[] data = yourKey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(data, 0, data.length,
algorithm);
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(fileData);
return decrypted;
}
}
这是错误代码段
07-01 14:50:48.230: W/System.err(11715): javax.crypto.IllegalBlockSizeException: last block incomplete in decryption
07-01 14:50:48.230: W/System.err(11715): at com.android.org.bouncycastle.jcajce.provider.symmetric.util.BaseBlockCipher.engineDoFinal(BaseBlockCipher.java:705)
07-01 14:50:48.230: W/System.err(11715): at javax.crypto.Cipher.doFinal(Cipher.java:1111)
07-01 14:50:48.230: W/System.err(11715): at com.cdac.authenticationl3.Cryptography.decodeFile(Cryptography.java:170)
07-01 14:50:48.230: W/System.err(11715): at com.cdac.authenticationl3.Cryptography.decryptString(Cryptography.java:95)
答案 0 :(得分：0)
您正在使用AES / ECB / PKCS5Padding来解密文件，但在加密文件时却没有。 添加AES / ECB / PKCS5Padding也用于加密过程。所以它应该是
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
希望这有帮助