javax.crypto.IllegalBlockSizeException: last block incomplete in decryption exception
15,102
Solution 1
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, 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;
}
Solution 2
salt.getBytes()
should be salt.getBytes(UNICODE_FORMAT)
Comments
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sravanalakshmi.sunkara almost 2 years
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; }
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Sharjeel Ahmed about 10 yearsYou need to explain what you changed, dont just post code without explanation.
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mochadwi about 5 years@sravanalakshmi-sunkara there's no Base64.NO_OPTIONS available: - no_padding, no_wrap, no_close only
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Maarten Bodewes about 5 yearsWarning: this code uses ECB, using a hidden, default string ("AES" is "AES/ECB/PKCS5Padding" for most providers). ECB mode is not secure.