I'm trying to decrypt a String text with the AES algorithm and I found many tutorials but still getting the same error when I try to decrypt the String.
Here is my class:
EditText inputText, inputPass;
TextView out;
Button btnEnc, btnDec;
String outputString;
private static final String AES_MODE = "AES";
View.OnClickListener encryption= new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
outputString= encrypt(inputText.getText().toString(),inputPass.getText().toString());
} catch (Exception e) {
e.printStackTrace();
}
out.setText(outputString);
}
};
View.OnClickListener decryption= new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
outputString= decrypt(outputString,inputPass.getText().toString());
} catch (Exception e) {
Toast.makeText(getApplicationContext(),e.getMessage(),Toast.LENGTH_LONG).show();
e.printStackTrace();
}
out.setText(outputString);
}
};
private String encrypt(String data, String pass)throws Exception{
SecretKeySpec key= generateKey(pass);
Cipher c= Cipher.getInstance(AES_MODE);
c.init(Cipher.ENCRYPT_MODE,key);
byte[] encVal= c.doFinal(data.getBytes());
String encryptedValue= Base64.encodeToString(encVal,Base64.DEFAULT);
return encryptedValue;
}
private String decrypt(String cadena, String password)throws Exception{
SecretKeySpec keySpec= generateKey(password);
Cipher c= Cipher.getInstance(AES_MODE);
c.init(Cipher.DECRYPT_MODE,keySpec);
byte[] decValue= Base64.decode(cadena, Base64.DEFAULT);
String decryptedValue= new String((decValue));
return decryptedValue;
}
private SecretKeySpec generateKey(String password) throws NoSuchAlgorithmException, UnsupportedEncodingException {
final MessageDigest digest= MessageDigest.getInstance("SHA-256");
byte[] bytes= password.getBytes("UTF-8");
digest.update(bytes,0,bytes.length);
byte[] key= digest.digest();
SecretKeySpec secretKeySpec= new SecretKeySpec(key, "AES");
return secretKeySpec;
}
The problem is when I try to retrieve the Decrypted string because it returns this:
As you can see, the output text contains Unicode characters and not the text that I've encrypted. What would be the problem?
You forgot to actually call your cipher in the decrypt method.
private String decrypt(String cadena, String password)throws Exception{
SecretKeySpec keySpec= generateKey(password);
Cipher c= Cipher.getInstance(AES_MODE);
c.init(Cipher.DECRYPT_MODE,keySpec);
byte[] decValue= c.doFinal(Base64.decode(cadena, Base64.DEFAULT));
// ^^^^^^^^^ add this
String decryptedValue= new String((decValue));
return decryptedValue;
}
Furthermore, you should always explicitly specify an encoding when converting from a byte[] to a String or vice versa.
Related
I have facing issue after applying encryption into a string, I want to decrypt that encrypted_string to a normal string, But none of the examples is working.
Also, they are working for byte array code, Byte_array encrypted and decrypted very well, But I need this working for the string.
Example, I tried already,
How to encrypt and decrypt String with my passphrase in Java (Pc not mobile platform)?
public static String encrypt(String strClearText,String strKey) throws Exception{
String strData="";
try {
SecretKeySpec skeyspec=new SecretKeySpec(strKey.getBytes(),"Blowfish");
Cipher cipher=Cipher.getInstance("Blowfish");
cipher.init(Cipher.ENCRYPT_MODE, skeyspec);
byte[] encrypted=cipher.doFinal(strClearText.getBytes());
strData=new String(encrypted);
} catch (Exception e) {
e.printStackTrace();
throw new Exception(e);
}
return strData;
}
public static String decrypt(String strEncrypted,String strKey) throws Exception{
String strData="";
try {
SecretKeySpec skeyspec=new SecretKeySpec(strKey.getBytes(),"Blowfish");
Cipher cipher=Cipher.getInstance("Blowfish");
cipher.init(Cipher.DECRYPT_MODE, skeyspec);
byte[] decrypted=cipher.doFinal(strEncrypted.getBytes());
strData=new String(decrypted);
} catch (Exception e) {
e.printStackTrace();
throw new Exception(e);
}
return strData;
}
String to byte[] then byte[] to string conversion not working properly?
You can use Base64 enocde and decode.
Example:
package test;
import java.util.Base64;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
public class Test2 {
public static void main(String[] args) throws Exception {
String key = "abc123!";
String encrypted = encrypt("test", key);
System.out.println(encrypted);
String decrypted = decrypt(encrypted, key);
System.out.println(decrypted);
}
public static String encrypt(String strClearText, String strKey) throws Exception {
String strData = "";
try {
SecretKeySpec skeyspec = new SecretKeySpec(strKey.getBytes(), "Blowfish");
Cipher cipher = Cipher.getInstance("Blowfish");
cipher.init(Cipher.ENCRYPT_MODE, skeyspec);
byte[] encrypted = cipher.doFinal(Base64.getDecoder().decode(strClearText));
strData = Base64.getEncoder().encodeToString(encrypted);
} catch (Exception e) {
e.printStackTrace();
throw new Exception(e);
}
return strData;
}
public static String decrypt(String strEncrypted, String strKey) throws Exception {
String strData = "";
try {
SecretKeySpec skeyspec = new SecretKeySpec(strKey.getBytes(), "Blowfish");
Cipher cipher = Cipher.getInstance("Blowfish");
cipher.init(Cipher.DECRYPT_MODE, skeyspec);
byte[] decrypted = cipher.doFinal(Base64.getDecoder().decode(strEncrypted));
strData = Base64.getEncoder().encodeToString(decrypted);
} catch (Exception e) {
e.printStackTrace();
throw new Exception(e);
}
return strData;
}
}
Output:
Fsmwp8c1n9w=
test
Here simple encoding and decoding (above kitkat)
Write this class and just call method
class EncodeDecode
{
public String encodeString(String text)
{
String b64;
byte[] data=new byte[0];
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT)
{
data=text.getBytes(StandardCharsets.UTF_8);
b64=Base64.encodeToString(data,Base64.DEFAULT);
}
return b64;
}
public String decodeString(String text)
{
String deString;
if(android.os.Build.VERSION.SDK_INT>=android.os.Build.VERSION_CODES.KITKAT)
{
byte[] data2=Base64.decode(base64,Base64.DEFAULT);
deString=new String (data2,StandardCharsets.UTF_8);
}
return deString;
}
}
I hope this answer will help you..
Im trying to decrypt the encrypted xml file. Im getting it as a inputstream as follows.I have the correct encrypt key. but each time my program returns empty string. Every time i enter the correct key. but each time it returns Badpadding Exception.
try{
InputStream is = new ByteArrayInputStream(decryption.getFileData().getBytes());
String xmlEncryptedStr = getStringFromInputStream(is);
String xmlStr = CipherUtils.decrypt(xmlEncryptedStr, new Long(key));
.......
here is my CipherUtils.java class
.........
public static String decrypt(String strToDecrypt,Long key)
{
String keyString=String.format("%016d", key);
//System.out.println("decrypt keyString :"+keyString);
return decrypt(strToDecrypt, keyString.getBytes());
}
public static String decrypt(String strToDecrypt,byte[] key)
{
if(strToDecrypt==null)
return strToDecrypt;
try
{
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
final SecretKeySpec secretKey = new SecretKeySpec(key, "AES");
cipher.init(Cipher.DECRYPT_MODE, secretKey);
final String decryptedString = new String(cipher.doFinal(Base64.decodeBase64(strToDecrypt)));
System.out.println("CipherUtils.decryptedString :"+decryptedString);
return decryptedString;
}
catch (Exception e)
{
log.error("Ops!", e);
}
return null;
}
.......
For more information here is my encrypting code
public static String encrypt(String strToEncrypt,Long key)
{
String keyString=String.format("%016d", key);
//System.out.println("encrypt keyString :"+keyString);
return encrypt(strToEncrypt,keyString.getBytes());
}
public static String encrypt(String strToEncrypt,byte[] key)
{
if(strToEncrypt==null)
return strToEncrypt;
try
{
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
final SecretKeySpec secretKey = new SecretKeySpec(key, "AES");
cipher.init(Cipher.ENCRYPT_MODE, secretKey);
final String encryptedString = Base64.encodeBase64String(cipher.doFinal(strToEncrypt.getBytes()));
// System.out.println("CipherUtils.encrypt :"+encryptedString);
return encryptedString;
}
catch (Exception e)
{
e.printStackTrace();
}
return null;
}
I am sorry I couldn't comment so I am writing in answers section.
I faced this issue when I was using different keys though I was passing the same but i used CBC methodology.
Just to note that have you checked that encryption is also done by the AES/ECB/PKCS5Padding and not other format like AES/CBC/PKCS5Padding
Also check if key format for encryption is also having the same format like %016d of your keyValue. Also the key is 16 char long.
I created a simple AES and DESede encryption utility and it worked fine.
private static final byte[] keyValue = new String(
"CjxI&S#V&#DSA_S0dA-SDSA$").getBytes();
public static void main(String[] args) throws Exception {
Client cli = new Client();
System.out.println(cli.encrypt("your password for encryption"));
Client cli1 = new Client();
System.out.println(cli1.decrypt("fTsgVQtXvv49GynHazT4OGZ4Va1H57d+6AM+44Ex040="));
}
public String encrypt(String Data) throws Exception {
Key key = new SecretKeySpec(keyValue, "AES");
Cipher c = Cipher.getInstance("AES/ECB/PKCS5Padding");
c.init(Cipher.ENCRYPT_MODE, key);
byte[] encVal = c.doFinal(Data.getBytes());
String encryptedValue = DatatypeConverter.printBase64Binary(encVal);
// String encryptedValue = new BASE64Encoder().encode(encVal);
return encryptedValue;
}
public String decrypt(String encryptedData) throws Exception {
Key key = new SecretKeySpec(keyValue, "AES");
Cipher c = Cipher.getInstance("AES/ECB/PKCS5Padding");
c.init(Cipher.DECRYPT_MODE, key);
byte[] decordedValue = DatatypeConverter
.parseBase64Binary(encryptedData);
byte[] decValue = c.doFinal(decordedValue);
String decryptedValue = new String(decValue);
return decryptedValue;
}
hi, i try to implement aes in some open source code messaging application. for encrypted message, its work find to me. but i have difficulty to decrypt back message.
in this class, i can encrypted message and it work fine.
MessageActivity.java
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.message);
messageView = (TextView) findViewById(R.id.message_view);
final Button button = (Button) findViewById(R.id.btn_send);
final EditText message = (EditText) findViewById(R.id.edit_message);
this.setTitle("Group Chat");
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String str = message.getText().toString();
byte[] cipherText = null;
try {
cipherText = AESEncryption.encryptText(str, AESEncryption.thisKey());
} catch (Exception e) {
e.printStackTrace();
}
String msgStr = new String(cipherText);
addMessage("This phone", str);
message.setText("");
// Send to other clients as a group chat message
for (AllEncompasingP2PClient c : MeshNetworkManager.routingTable.values()) {
if (c.getMac().equals(MeshNetworkManager.getSelf().getMac()))
continue;
Sender.queuePacket(new Packet(Packet.TYPE.MESSAGE, msgStr.getBytes(), c.getMac(),
WiFiDirectBroadcastReceiver.MAC));
}
}
});
Receiver.java
/////////////// this messsage receiver part///////////////////////
byte[] thisMsg = p.getData();
String decryptedText = null;
try {
decryptedText = AESEncryption.decryptText(thisMsg, AESEncryption.thisKey());
} catch (Exception e) {
e.printStackTrace();
}
final String message = p.getSenderMac() + " says:\n" + decryptedText;
final String msg = new String(p.getData());
final String name = p.getSenderMac();
//////////////////////////////////////
if (!MeshNetworkManager.routingTable.contains(p.getSenderMac())) {
/*
* Update your routing table if for some reason this
* guy isn't in it
*/
MeshNetworkManager.routingTable.put(p.getSenderMac(),
new AllEncompasingP2PClient(p.getSenderMac(), p.getSenderIP(),
p.getSenderMac(),
MeshNetworkManager.getSelf().getGroupOwnerMac()));
}
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
if (activity.isVisible) {
Toast.makeText(activity, message, Toast.LENGTH_LONG).show();
} else {
MessageActivity.addMessage(name, msg);
}
}
});
updatePeerList();
AESEncryption.java
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
//import javax.xml.bind.DatatypeConverter;
public class AESEncryption {
public static SecretKey getSecretEncryptionKey() throws Exception{
KeyGenerator generator = KeyGenerator.getInstance("AES");
generator.init(128); // The AES key size in number of bits
SecretKey secKey = generator.generateKey();
return secKey;
}
public static byte[] encryptText(String plainText,SecretKey secKey) throws Exception{
// AES defaults to AES/ECB/PKCS5Padding in Java 7
Cipher aesCipher = Cipher.getInstance("AES");
aesCipher.init(Cipher.ENCRYPT_MODE, secKey);
byte[] byteCipherText = aesCipher.doFinal(plainText.getBytes());
return byteCipherText;
}
public static String decryptText(byte[] byteCipherText, SecretKey secKey) throws Exception {
// AES defaults to AES/ECB/PKCS5Padding in Java 7
Cipher aesCipher = Cipher.getInstance("AES");
aesCipher.init(Cipher.DECRYPT_MODE, secKey);
byte[] bytePlainText = aesCipher.doFinal(byteCipherText);
return new String(bytePlainText);
}
public static SecretKey thisKey() throws Exception{
SecretKey secKey = AESEncryption.getSecretEncryptionKey();
return secKey;
}
}
in this class where i code the decrypted message. but when i run the code, the messages not decrypt and show ciphert text instead.if someone can correct me, its will great.
The same key must be used for both encryption and decryption for the same message.
It seems the same key is not being used for both encryption and decryption, both methods call SecretKey thisKey() which seems to generate a random key.
On encryption call SecretKey thisKey(), use it for encryption and save the key to use on decryption. On decryption do not call SecretKey thisKey(), use the key created for encryption.
I have a stringBuilder message appended with "||" symbol.(Ex: Hi||How||are||26 04 2016||finish) i have to encrypt the message and send it to the server using AES and decrypt the same at the server side. Can anyone help me out in solving this?
You can encrypt and decrypt like this:
public class AES {
public static byte[] encrypt(String key, String initVector, String value) {
try {
IvParameterSpec vector = new IvParameterSpec(initVector.getBytes("UTF-8"));
SecretKeySpec secretKey = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.ENCRYPT_MODE, secretKey, vector);
byte[] encrypted = cipher.doFinal(value.getBytes());
System.out.println("encrypted string: "+ Base64.encodeBase64(encrypted));
return Base64.encodeBase64(encrypted);
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
public static String decrypt(String key, String initVector, byte[] encrypted) {
try {
IvParameterSpec vector = new IvParameterSpec(initVector.getBytes("UTF-8"));
SecretKeySpec secretKey = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.DECRYPT_MODE, secretKey, vector);
byte[] original = cipher.doFinal(Base64.decodeBase64(encrypted));
return new String(original);
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
public static void main(String[] args) {
String key = "Foo12345Bar67890"; // 128 bit key
String initVector = "RandomInitVector"; // 16 bytes IV
StringBuilder sb = new StringBuilder("Hi||How||are||26 04 2016||finish"); //Your Text here
byte[] encryptedBytes = encrypt(key, initVector, sb.toString());
System.out.println(decrypt(key, initVector,encryptedBytes));
}
}
I have written my program in java by following this tutorial http://www.java2s.com/Code/Android/Security/AESEncryption.htm
But i am getting an exception i.e. "javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher"
Can anybody help me?
public class utils {
public static String encrypt(String message,String secretPhrase){
try{
MessageDigest mdig=MessageDigest.getInstance("MD5");
byte[] digestedBytes=mdig.digest(secretPhrase.getBytes("UTF-8"));
SecretKeySpec keySpec=new SecretKeySpec(digestedBytes,"AES");
Cipher cipher=Cipher.getInstance("AES/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, keySpec);
byte[] encryptedBytes=cipher.doFinal(message.getBytes("UTF-8"));
return new String(encryptedBytes,"UTF-8");
}catch(Exception exc){
return null;
}
}
public static String decrypt(String message,String secretPhrase){
try{
MessageDigest mdig=MessageDigest.getInstance("MD5");
byte[] digestedBytes=mdig.digest(secretPhrase.getBytes("UTF-8"));
SecretKeySpec keySpec=new SecretKeySpec(digestedBytes,"AES");
Cipher cipher=Cipher.getInstance("AES/ECB/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, keySpec);
byte[] encryptedBytes=cipher.doFinal(message.getBytes("UTF-8"));
return new String(encryptedBytes,"UTF-8");
}catch(Exception exc){
return null;
}
}
}
Well try this ,
public String encrypt(String str) {
try {
// Encode the string into bytes using utf-8
byte[] utf8 = str.getBytes("UTF8");
// Encrypt
byte[] enc = ecipher.doFinal(utf8);
// Encode bytes to base64 to get a string
return new sun.misc.BASE64Encoder().encode(enc);
} catch (Exception e) {
}
return null;
}
public String decrypt(String str) {
try {
// Decode base64 to get bytes
byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);
// Decrypt
byte[] utf8 = dcipher.doFinal(dec);
// Decode using utf-8
return new String(utf8, "UTF8");
} catch (Exception e) {
}
return null;
}
Example using it
try {
// Generate a temporary key. In practice, you would save this key.
// See also Encrypting with DES Using a Pass Phrase.
SecretKey key = KeyGenerator.getInstance("DES").generateKey();
// Create encrypter/decrypter class
DesEncrypter encrypter = new DesEncrypter(key);
// Encrypt
String encrypted = encrypter.encrypt("Don't tell anybody!");
// Decrypt
String decrypted = encrypter.decrypt(encrypted);
} catch (Exception e) {
}