I have a problem with my code. I want to encrypt a message using a key made from passphrase. Then I want to send it (or use it somewhere, whatever) in String form (the encrypted one), and after that I want to decrypt it only by knowing the passphrase.
I wrote the code below, but I receive either IllegalBlockSizeException or BadPaddingException. I thought that badding would be took care by padding.
Here is my code:
Constructor and initialization:
public class AES_Cipher {
private String keyString;
private byte[] byteKey;
private SecretKey key;
Cipher c;
public AES_Cipher(String keyString){
this.keyString = keyString.toString();
}
public void init() throws InitializtionFailedException{
try{
c = Cipher.getInstance("AES/ECB/PKCS5Padding");
byteKey = keyString.getBytes("UTF-8");
MessageDigest sha = MessageDigest.getInstance("SHA-1");
byteKey = sha.digest(byteKey);
byteKey = Arrays.copyOf(byteKey, 16);
key = new SecretKeySpec(byteKey, "AES");
}catch(NoSuchAlgorithmException e){
throw new InitializtionFailedException();
}
}
Encrypt:
public String encrypt(String text) throws EncryptionException{
try{
c.init(Cipher.ENCRYPT_MODE, key);
byte[] tmp = c.doFinal( text.getBytes("UTF-8"));
return new String(tmp, "UTF-8");
}catch(IllegalBlockSizeException e){
throw new EncryptionException();
}
}
Decrypt:
public String decrypt(String text) throws DecryptionException{
try{
//byte[] decordedValue = new BASE64Decoder().decodeBuffer(text);
// tried too use it but with poor outcome
//c = Cipher.getInstance("AES/ECB/PKCS5Padding");
c.init(Cipher.DECRYPT_MODE, key);
byte[] tmp1 = text.getBytes("UTF-8");
//byte[] tmp = c.doFinal("aaaaaaaaaaaaaaaa".getBytes());
//this returns BadPaddingException
byte[] tmp = c.doFinal(text.getBytes());
return new String(tmp, "UTF-8");
}catch(IllegalBlockSizeException e){
throw new DecryptionException();
}
}
Of course there are some more exceptions.
Also, I would like to later use this code on android, and It doesn't need to be AES if there is some other Ciphers that are maybe less effective but less troublesome. But not simple XOR if that's not too much too ask.
Thank you in advance.
Ok. Seems to work now thanks to Artjom B.
Constructor and inicialization:
public class AES_Cipher {
private String keyString;
private byte[] byteKey;
private SecretKey key;
Cipher c;
public AES_Cipher(String keyString){
this.keyString = keyString.toString();
}
public void init() throws InitializtionFailedException{
try{
c = Cipher.getInstance("AES/ECB/PKCS5Padding");
byteKey = keyString.getBytes("UTF-8");
MessageDigest sha = MessageDigest.getInstance("SHA-1");
byteKey = sha.digest(byteKey);
byteKey = Arrays.copyOf(byteKey, 16);
key = new SecretKeySpec(byteKey, "AES");
}catch(NoSuchAlgorithmException e){
throw new InitializtionFailedException();
}
}
Encryption:
public String encrypt(String text) throws EncryptionException{
try{
c.init(Cipher.ENCRYPT_MODE, key);
byte[] textByte = text.getBytes("UTF-8");
byte[] tmp = c.doFinal(textByte);
String return1 = Base64.encodeToString(tmp, Base64.DEFAULT);
return return1;
} // of course there is some exceptions catched down there
Decryption:
public String decrypt(String text) throws DecryptionException{
try{
c.init(Cipher.DECRYPT_MODE, key);
byte[] textByte = Base64.decode(text, Base64.DEFAULT);
byte[] tmp = c.doFinal(textByte);
return new String(tmp, "UTF-8");
}catch(IllegalBlockSizeException e){
Log.d("Exception", "IllegalBlockSizeException");
throw new DecryptionException();
} // wrote DecryptionException myself.
// also there is more Exceptions below
}
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Is there any good example of how to encrypt and decrypt image and other files with AES on Android?
Warning: This answer contains code you should not use as it is insecure (using SHA1PRNG for key derivation and using AES in ECB mode)
Instead (as of 2016), use PBKDF2WithHmacSHA1 for key derivation and AES in CBC or GCM mode (GCM provides both privacy and integrity)
You could use functions like these:
private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(clear);
return encrypted;
}
private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(encrypted);
return decrypted;
}
And invoke them like this:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.PNG, 100, baos); // bm is the bitmap object
byte[] b = baos.toByteArray();
byte[] keyStart = "this is a key".getBytes();
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(keyStart);
kgen.init(128, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] key = skey.getEncoded();
// encrypt
byte[] encryptedData = encrypt(key,b);
// decrypt
byte[] decryptedData = decrypt(key,encryptedData);
This should work, I use similar code in a project right now.
As mentioned by Nacho.L PBKDF2WithHmacSHA1 derivation is used as it is more secured.
import android.util.Base64;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
public class AESEncyption {
private static final int pswdIterations = 10;
private static final int keySize = 128;
private static final String cypherInstance = "AES/CBC/PKCS5Padding";
private static final String secretKeyInstance = "PBKDF2WithHmacSHA1";
private static final String plainText = "sampleText";
private static final String AESSalt = "exampleSalt";
private static final String initializationVector = "8119745113154120";
public static String encrypt(String textToEncrypt) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(getRaw(plainText, AESSalt), "AES");
Cipher cipher = Cipher.getInstance(cypherInstance);
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, new IvParameterSpec(initializationVector.getBytes()));
byte[] encrypted = cipher.doFinal(textToEncrypt.getBytes());
return Base64.encodeToString(encrypted, Base64.DEFAULT);
}
public static String decrypt(String textToDecrypt) throws Exception {
byte[] encryted_bytes = Base64.decode(textToDecrypt, Base64.DEFAULT);
SecretKeySpec skeySpec = new SecretKeySpec(getRaw(plainText, AESSalt), "AES");
Cipher cipher = Cipher.getInstance(cypherInstance);
cipher.init(Cipher.DECRYPT_MODE, skeySpec, new IvParameterSpec(initializationVector.getBytes()));
byte[] decrypted = cipher.doFinal(encryted_bytes);
return new String(decrypted, "UTF-8");
}
private static byte[] getRaw(String plainText, String salt) {
try {
SecretKeyFactory factory = SecretKeyFactory.getInstance(secretKeyInstance);
KeySpec spec = new PBEKeySpec(plainText.toCharArray(), salt.getBytes(), pswdIterations, keySize);
return factory.generateSecret(spec).getEncoded();
} catch (InvalidKeySpecException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
return new byte[0];
}
}
import java.security.AlgorithmParameters;
import java.security.SecureRandom;
import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
class SecurityUtils {
private static final byte[] salt = { (byte) 0xA4, (byte) 0x0B, (byte) 0xC8,
(byte) 0x34, (byte) 0xD6, (byte) 0x95, (byte) 0xF3, (byte) 0x13 };
private static int BLOCKS = 128;
public static byte[] encryptAES(String seed, String cleartext)
throws Exception {
byte[] rawKey = getRawKey(seed.getBytes("UTF8"));
SecretKeySpec skeySpec = new SecretKeySpec(rawKey, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
return cipher.doFinal(cleartext.getBytes("UTF8"));
}
public static byte[] decryptAES(String seed, byte[] data) throws Exception {
byte[] rawKey = getRawKey(seed.getBytes("UTF8"));
SecretKeySpec skeySpec = new SecretKeySpec(rawKey, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
return cipher.doFinal(data);
}
private static byte[] getRawKey(byte[] seed) throws Exception {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(seed);
kgen.init(BLOCKS, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
return raw;
}
private static byte[] pad(byte[] seed) {
byte[] nseed = new byte[BLOCKS / 8];
for (int i = 0; i < BLOCKS / 8; i++)
nseed[i] = 0;
for (int i = 0; i < seed.length; i++)
nseed[i] = seed[i];
return nseed;
}
public static byte[] encryptPBE(String password, String cleartext)
throws Exception {
SecretKeyFactory factory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, 1024, 256);
SecretKey tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secret);
AlgorithmParameters params = cipher.getParameters();
byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
return cipher.doFinal(cleartext.getBytes("UTF-8"));
}
public static String decryptPBE(SecretKey secret, String ciphertext,
byte[] iv) throws Exception {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv));
return new String(cipher.doFinal(ciphertext.getBytes()), "UTF-8");
}
}
For AES/CBC/PKCS7 encryption/decryption, Just Copy and paste the following code and replace SecretKey and IV with your own.
import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import android.util.Base64;
public class CryptoHandler {
String SecretKey = "xxxxxxxxxxxxxxxxxxxx";
String IV = "xxxxxxxxxxxxxxxx";
private static CryptoHandler instance = null;
public static CryptoHandler getInstance() {
if (instance == null) {
instance = new CryptoHandler();
}
return instance;
}
public String encrypt(String message) throws NoSuchAlgorithmException,
NoSuchPaddingException, IllegalBlockSizeException,
BadPaddingException, InvalidKeyException,
UnsupportedEncodingException, InvalidAlgorithmParameterException {
byte[] srcBuff = message.getBytes("UTF8");
//here using substring because AES takes only 16 or 24 or 32 byte of key
SecretKeySpec skeySpec = new
SecretKeySpec(SecretKey.substring(0,32).getBytes(), "AES");
IvParameterSpec ivSpec = new
IvParameterSpec(IV.substring(0,16).getBytes());
Cipher ecipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
ecipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivSpec);
byte[] dstBuff = ecipher.doFinal(srcBuff);
String base64 = Base64.encodeToString(dstBuff, Base64.DEFAULT);
return base64;
}
public String decrypt(String encrypted) throws NoSuchAlgorithmException,
NoSuchPaddingException, InvalidKeyException,
InvalidAlgorithmParameterException, IllegalBlockSizeException,
BadPaddingException, UnsupportedEncodingException {
SecretKeySpec skeySpec = new
SecretKeySpec(SecretKey.substring(0,32).getBytes(), "AES");
IvParameterSpec ivSpec = new
IvParameterSpec(IV.substring(0,16).getBytes());
Cipher ecipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
ecipher.init(Cipher.DECRYPT_MODE, skeySpec, ivSpec);
byte[] raw = Base64.decode(encrypted, Base64.DEFAULT);
byte[] originalBytes = ecipher.doFinal(raw);
String original = new String(originalBytes, "UTF8");
return original;
}
}
Old question but I upgrade the answers supporting Android prior and post 4.2 and considering all recent changes according to Android developers blog
Plus I leave a working example on my github repo.
import java.nio.charset.Charset;
import java.security.AlgorithmParameters;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;
/*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will Google be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, as long as the origin is not misrepresented.
*
* #author: Ricardo Champa
*
*/
public class MyCipher {
private final static String ALGORITHM = "AES";
private String mySecret;
public MyCipher(String mySecret){
this.mySecret = mySecret;
}
public MyCipherData encryptUTF8(String data){
try{
byte[] bytes = data.toString().getBytes("utf-8");
byte[] bytesBase64 = Base64.encodeBase64(bytes);
return encrypt(bytesBase64);
}
catch(Exception e){
MyLogs.show(e.getMessage());
return null;
}
}
public String decryptUTF8(byte[] encryptedData, IvParameterSpec iv){
try {
byte[] decryptedData = decrypt(encryptedData, iv);
byte[] decodedBytes = Base64.decodeBase64(decryptedData);
String restored_data = new String(decodedBytes, Charset.forName("UTF8"));
return restored_data;
} catch (Exception e) {
MyLogs.show(e.getMessage());;
return null;
}
}
//AES
private MyCipherData encrypt(byte[] raw, byte[] clear) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, ALGORITHM);
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
//solved using PRNGFixes class
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] data = cipher.doFinal(clear);
AlgorithmParameters params = cipher.getParameters();
byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
return new MyCipherData(data, iv);
}
private byte[] decrypt(byte[] raw, byte[] encrypted, IvParameterSpec iv) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, ALGORITHM);
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
byte[] decrypted = cipher.doFinal(encrypted);
return decrypted;
}
private byte[] getKey() throws Exception{
byte[] keyStart = this.mySecret.getBytes("utf-8");
KeyGenerator kgen = KeyGenerator.getInstance(ALGORITHM);
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
// if (android.os.Build.VERSION.SDK_INT >= 17) {
// sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
// } else {
// sr = SecureRandom.getInstance("SHA1PRNG");
// }
sr.setSeed(keyStart);
kgen.init(128, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] key = skey.getEncoded();
return key;
}
////////////////////////////////////////////////////////////
private MyCipherData encrypt(byte[] data) throws Exception{
return encrypt(getKey(),data);
}
private byte[] decrypt(byte[] encryptedData, IvParameterSpec iv) throws Exception{
return decrypt(getKey(),encryptedData, iv);
}
}
If you are encrypting a text file, then the following test/sample may be useful. It does the following:
Create a byte stream,
wraps that with AES encryption,
wrap it next with text processing
and lastly buffers it
// AESdemo
public class AESdemo extends Activity {
boolean encryptionIsOn = true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_aesdemo);
// needs <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
String homeDirName = Environment.getExternalStorageDirectory().getAbsolutePath() +
"/" + getPackageName();
File file = new File(homeDirName, "test.txt");
byte[] keyBytes = getKey("password");
try {
File dir = new File(homeDirName);
if (!dir.exists())
dir.mkdirs();
if (!file.exists())
file.createNewFile();
OutputStreamWriter osw;
if (encryptionIsOn) {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, "AES");
IvParameterSpec ivParameterSpec = new IvParameterSpec(keyBytes);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
FileOutputStream fos = new FileOutputStream(file);
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
osw = new OutputStreamWriter(cos, "UTF-8");
}
else // not encryptionIsOn
osw = new FileWriter(file);
BufferedWriter out = new BufferedWriter(osw);
out.write("This is a test\n");
out.close();
}
catch (Exception e) {
System.out.println("Encryption Exception "+e);
}
///////////////////////////////////
try {
InputStreamReader isr;
if (encryptionIsOn) {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, "AES");
IvParameterSpec ivParameterSpec = new IvParameterSpec(keyBytes);
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);
FileInputStream fis = new FileInputStream(file);
CipherInputStream cis = new CipherInputStream(fis, cipher);
isr = new InputStreamReader(cis, "UTF-8");
}
else
isr = new FileReader(file);
BufferedReader in = new BufferedReader(isr);
String line = in.readLine();
System.out.println("Text read: <"+line+">");
in.close();
}
catch (Exception e) {
System.out.println("Decryption Exception "+e);
}
}
private byte[] getKey(String password) throws UnsupportedEncodingException {
String key = "";
while (key.length() < 16)
key += password;
return key.substring(0, 16).getBytes("UTF-8");
}
}
AES encrypt/decrypt in android
String encData= encrypt("keykey".getBytes("UTF-16LE"), ("0123000000000215").getBytes("UTF-16LE"));
String decData= decrypt("keykey",Base64.decode(encData.getBytes("UTF-16LE"), Base64.DEFAULT));
encrypt function
private static String encrypt(byte[] key, byte[] clear) throws Exception
{
MessageDigest md = MessageDigest.getInstance("md5");
byte[] digestOfPassword = md.digest(key);
SecretKeySpec skeySpec = new SecretKeySpec(digestOfPassword, "AES");
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(clear);
return Base64.encodeToString(encrypted,Base64.DEFAULT);
}
decrypt function
private static String decrypt(String key, byte[] encrypted) throws Exception
{
MessageDigest md = MessageDigest.getInstance("md5");
byte[] digestOfPassword = md.digest(key.getBytes("UTF-16LE"));
SecretKeySpec skeySpec = new SecretKeySpec(digestOfPassword, "AES");
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(encrypted);
return new String(decrypted, "UTF-16LE");
}
AES encrypt/decrypt in c#
static void Main(string[] args)
{
string enc = encryptAES("0123000000000215", "keykey");
string dec = decryptAES(enc, "keykey");
Console.ReadKey();
}
encrypt function
public static string encryptAES(string input, string key)
{
var plain = Encoding.Unicode.GetBytes(input);
// 128 bits
AesCryptoServiceProvider provider = new AesCryptoServiceProvider();
provider.KeySize = 128;
provider.Mode = CipherMode.ECB;
provider.Padding = PaddingMode.PKCS7;
provider.Key = CalculateMD5Hash(key);
var enc = provider.CreateEncryptor().TransformFinalBlock(plain, 0, plain.Length);
return Convert.ToBase64String(enc);
}
decrypt function
public static string decryptAES(string encryptText, string key)
{
byte[] enc = Convert.FromBase64String(encryptText);
// 128 bits
AesCryptoServiceProvider provider = new AesCryptoServiceProvider();
provider.KeySize = 128;
provider.Mode = CipherMode.ECB;
provider.Padding = PaddingMode.PKCS7;
provider.Key = CalculateMD5Hash(key);
var dec = provider.CreateDecryptor().TransformFinalBlock(enc, 0, enc.Length);
return Encoding.Unicode.GetString(dec);
}
create md5
public static byte[] CalculateMD5Hash(string input)
{
MD5 md5 = MD5.Create();
byte[] inputBytes = Encoding.Unicode.GetBytes(input);
return md5.ComputeHash(inputBytes);
}
Simple API to perform AES encryption on Android. This is the Android counterpart to the AESCrypt library Ruby and Obj-C (with the same defaults):
https://github.com/scottyab/AESCrypt-Android
Here is simple code snippet working for AES Encryption and Decryption.
import android.util.Base64;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
public class AESEncryptionClass {
private static String INIT_VECTOR_PARAM = "#####";
private static String PASSWORD = "#####";
private static String SALT_KEY = "#####";
private static SecretKeySpec generateAESKey() throws NoSuchAlgorithmException, InvalidKeySpecException {
// Prepare password and salt key.
char[] password = new String(Base64.decode(PASSWORD, Base64.DEFAULT)).toCharArray();
byte[] salt = new String(Base64.decode(SALT_KEY, Base64.DEFAULT)).getBytes(StandardCharsets.UTF_8);
// Create object of [Password Based Encryption Key Specification] with required iteration count and key length.
KeySpec spec = new PBEKeySpec(password, salt, 64, 256);
// Now create AES Key using required hashing algorithm.
SecretKey key = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1").generateSecret(spec);
// Get encoded bytes of secret key.
byte[] bytesSecretKey = key.getEncoded();
// Create specification for AES Key.
SecretKeySpec secretKeySpec = new SecretKeySpec(bytesSecretKey, "AES");
return secretKeySpec;
}
/**
* Call this method to encrypt the readable plain text and get Base64 of encrypted bytes.
*/
public static String encryptMessage(String message) throws BadPaddingException, IllegalBlockSizeException, NoSuchPaddingException, NoSuchAlgorithmException, UnsupportedEncodingException, InvalidKeySpecException, InvalidAlgorithmParameterException, InvalidKeyException {
byte[] initVectorParamBytes = new String(Base64.decode(INIT_VECTOR_PARAM, Base64.DEFAULT)).getBytes(StandardCharsets.UTF_8);
Cipher encryptionCipherBlock = Cipher.getInstance("AES/CBC/PKCS5Padding");
encryptionCipherBlock.init(Cipher.ENCRYPT_MODE, generateAESKey(), new IvParameterSpec(initVectorParamBytes));
byte[] messageBytes = message.getBytes();
byte[] cipherTextBytes = encryptionCipherBlock.doFinal(messageBytes);
String encryptedText = Base64.encodeToString(cipherTextBytes, Base64.DEFAULT);
return encryptedText;
}
/**
* Call this method to decrypt the Base64 of encrypted message and get readable plain text.
*/
public static String decryptMessage(String base64Cipher) throws BadPaddingException, IllegalBlockSizeException, NoSuchPaddingException, NoSuchAlgorithmException, UnsupportedEncodingException, InvalidKeySpecException, InvalidAlgorithmParameterException, InvalidKeyException {
byte[] initVectorParamBytes = new String(Base64.decode(INIT_VECTOR_PARAM, Base64.DEFAULT)).getBytes(StandardCharsets.UTF_8);
Cipher decryptionCipherBlock = Cipher.getInstance("AES/CBC/PKCS5Padding");
decryptionCipherBlock.init(Cipher.DECRYPT_MODE, generateAESKey(), new IvParameterSpec(initVectorParamBytes));
byte[] cipherBytes = Base64.decode(base64Cipher, Base64.DEFAULT);
byte[] messageBytes = decryptionCipherBlock.doFinal(cipherBytes);
String plainText = new String(messageBytes);
return plainText;
}
}
Now, call encryptMessage() or decryptMessage() for desired AES Operation with required parameters.
Also, handle the exceptions during AES operations.
Hope it helped...
To add bouncy castle to Android project: https://mvnrepository.com/artifact/org.bouncycastle/bcprov-jdk16/1.45
Add this line in your Main Activity:
static {
Security.addProvider(new BouncyCastleProvider());
}
public class AESHelper {
private static final String TAG = "AESHelper";
public static byte[] encrypt(byte[] data, String initVector, String key) {
try {
IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
Cipher c = Cipher.getInstance("AES/CBC/PKCS5PADDING");
SecretKeySpec k = new SecretKeySpec(Base64.decode(key, Base64.DEFAULT), "AES");
c.init(Cipher.ENCRYPT_MODE, k, iv);
return c.doFinal(data);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
public static byte[] decrypt(byte[] data, String initVector, String key) {
try {
IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
Cipher c = Cipher.getInstance("AES/CBC/PKCS5PADDING");
SecretKeySpec k = new SecretKeySpec(Base64.decode(key, Base64.DEFAULT), "AES");
c.init(Cipher.DECRYPT_MODE, k, iv);
return c.doFinal(data);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
public static String keyGenerator() throws NoSuchAlgorithmException {
KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
keyGenerator.init(192);
return Base64.encodeToString(keyGenerator.generateKey().getEncoded(),
Base64.DEFAULT);
}
}