sravanalakshmi.sunkara sravanalakshmi.sunkara - 2 months ago 5
Java Question

javax.crypto.IllegalBlockSizeException: last block incomplete in decryption exception in android

I am trying to decrypt a string in android. I keep getting the following exception:

08-21 03:56:56.700: W/System.err(4208): javax.crypto.IllegalBlockSizeException: last block incomplete in decryption
08-21 03:56:56.700: W/System.err(4208): at com.android.org.bouncycastle.jce.provider.JCEBlockCipher.engineDoFinal(JCEBlockCipher.java:697)
08-21 03:56:56.700: W/System.err(4208): at javax.crypto.Cipher.doFinal(Cipher.java:1106)
08-21 03:56:56.700: W/System.err(4208): at com.dharani.android.legalplex.BusinessLayer.BLCommonOperations.decrypt(BLCommonOperations.java:284)
08-21 03:56:56.700: W/System.err(4208): at com.dharani.android.legalplex.BusinessLayer.BLCommonOperations.decryptAndgetFailCountFromPreferences(BLCommonOperations.java:144)
08-21 03:56:56.700: W/System.err(4208): at com.dharani.android.legalplex.PresentationLayer.TransparentActivity.onCreate(TransparentActivity.java:112)
08-21 03:56:56.700: W/System.err(4208): at android.app.Activity.performCreate(Activity.java:4465)
08-21 03:56:56.700: W/System.err(4208): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1052)
08-21 03:56:56.700: W/System.err(4208): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1932)
08-21 03:56:56.700: W/System.err(4208): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1993)
08-21 03:56:56.700: W/System.err(4208): at android.app.ActivityThread.access$600(ActivityThread.java:127)
08-21 03:56:56.700: W/System.err(4208): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1159)
08-21 03:56:56.700: W/System.err(4208): at android.os.Handler.dispatchMessage(Handler.java:99)
08-21 03:56:56.700: W/System.err(4208): at android.os.Looper.loop(Looper.java:137)
08-21 03:56:56.700: W/System.err(4208): at android.app.ActivityThread.main(ActivityThread.java:4507)
08-21 03:56:56.700: W/System.err(4208): at java.lang.reflect.Method.invokeNative(Native Method)
08-21 03:56:56.700: W/System.err(4208): at java.lang.reflect.Method.invoke(Method.java:511)
08-21 03:56:56.700: W/System.err(4208): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
08-21 03:56:56.700: W/System.err(4208): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
08-21 03:56:56.700: W/System.err(4208): at dalvik.system.NativeStart.main(Native Method)


the encrypt and decrypt methods are

public String encrypt(String message) throws Exception
{
String salt = SharedVariables.globalContext.getString(R.string.EncryptionKey);
SecretKeySpec key = new SecretKeySpec(salt.getBytes(), "AES");
Cipher c = Cipher.getInstance("AES");
c.init(Cipher.ENCRYPT_MODE, key);
byte[] encVal = c.doFinal(message.getBytes());
String encrypted=Base64.encodeToString(encVal, Base64.DEFAULT);
return encrypted;
}

public String decrypt(String message) throws Exception
{
String salt = SharedVariables.globalContext.getString(R.string.EncryptionKey);
Cipher c = Cipher.getInstance("AES");
SecretKeySpec key = new SecretKeySpec(salt.getBytes(), "AES");
c.init(Cipher.DECRYPT_MODE, key);
byte[] decordedValue = Base64.decode(message.getBytes(), Base64.DEFAULT);
byte[] decValue = c.doFinal(decordedValue);
String decryptedValue = new String(decValue);
return decryptedValue;
}


Edit



I got the solution.Following is new code that worked for me

// Encryption
public String encrypt(String message) throws Exception
{
String message1=Base64.encodeBytes(message.getBytes(),Base64.NO_OPTIONS);
String salt = SharedVariables.globalContext.getString(R.string.EncryptionKey);
SecretKeySpec key = new SecretKeySpec(salt.getBytes(), "AES");
Cipher c = Cipher.getInstance("AES");
c.init(Cipher.ENCRYPT_MODE, key);
byte[] encVal = c.doFinal(message1.getBytes());
String encrypted=Base64.encodeToString(encVal, com.dharani.android.legalplex.BusinessLayer.Base64.NO_OPTIONS);
return encrypted;
}

//Decryption
public String decrypt(String message) throws Exception
{
// String message1=Base64.encodeBytes(message.getBytes(),com.dharani.android.legalplex.BusinessLayer.Base64.NO_OPTIONS);
String salt = SharedVariables.globalContext.getString(R.string.EncryptionKey);
Cipher c = Cipher.getInstance("AES");
SecretKeySpec key = new SecretKeySpec(salt.getBytes(), "AES");
c.init(Cipher.DECRYPT_MODE, key);
byte[] decordedValue = Base64.decode(message.getBytes(), Base64.NO_OPTIONS);
byte[] decValue = c.doFinal(decordedValue);
String decryptedValue = new String(decValue);
String decoded=new String(com.dharani.android.legalplex.BusinessLayer.Base64.decode(decryptedValue, com.dharani.android.legalplex.BusinessLayer.Base64.NO_OPTIONS));
return decoded;
}

Answer

I got the solution.Following is new code that worked for me

// Encryption

public  String encrypt(String message) throws Exception

{

String message1=Base64.encodeBytes(message.getBytes(),Base64.NO_OPTIONS);
String salt = SharedVariables.globalContext.getString(R.string.EncryptionKey);
SecretKeySpec key = new SecretKeySpec(salt.getBytes(), "AES");`enter code here`
Cipher c = Cipher.getInstance("AES");
c.init(Cipher.ENCRYPT_MODE, key);
byte[] encVal = c.doFinal(message1.getBytes());
String encrypted=Base64.encodeToString(encVal, Base64.NO_OPTIONS);
return encrypted;

}

//Decryption

public String decrypt(String message) throws Exception

{

String salt = SharedVariables.globalContext.getString(R.string.EncryptionKey);
Cipher c = Cipher.getInstance("AES");
SecretKeySpec key = new SecretKeySpec(salt.getBytes(), "AES");
c.init(Cipher.DECRYPT_MODE, key);
byte[] decordedValue = Base64.decode(message.getBytes(), Base64.NO_OPTIONS);
byte[] decValue = c.doFinal(decordedValue);
String decryptedValue = new String(decValue);
String decoded=new String(Base64.decode(decryptedValue, .Base64.NO_OPTIONS));
return decoded;
} 
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