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I am getting BadPaddingException while decrypting an 128 bit AES key which has been encoded by using RSA generated public key(.jks)

package demo123;
import java.io.File;
import java.io.FileInputStream;
import java.nio.file.Files;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
// Java 8 example for RSA-AES encryption/decryption.
public class AESwithRSA {
public static void main(String[] args) throws Exception {
String plainText = "{\"scope\":\"payments\",\"x-mig-bank\": \"ICICI\",\"x-mig-channel\": \"RC\",\"tpp_redirect_uri\": \"www.tpp-app.com?query=123\",\"x-tpp-client-id\": \"Ck234567890112\",\"tpp-app-name\": \"amazon\",\"Consent Id\": \"d25a6f26-3ad5-4dd8-96fd-2582abfa3f58\",\"Type\": \"Domestic Payment\" }";
// Generate public and private keys using RSA
Key privateKey = getPrivate("KeyPair/privateKey.jks");
System.out.println("Private key success");
System.out.println("Private key :" + privateKey);
Key publicKey = getPublic("KeyPair/publicKey.");
System.out.println("Public key success");
System.out.println("Public key :" + publicKey);
// First create an AES Key
String secretAESKeyString = getSecretAESKeyAsString();
System.out.println("Secret Key "+secretAESKeyString);
// Encrypt our data with AES key
String encryptedText = encryptTextUsingAES(plainText, secretAESKeyString);
System.out.println("Encrypted text "+encryptedText);
// Encrypt AES Key with RSA Private Key
byte[] encryptedAESKeyString = encryptAESKey(secretAESKeyString, publicKey);
System.out.println("Encrypted AES key with RSA "+encryptedAESKeyString);
// First decrypt the AES Key with RSA Public key
String decryptedAESKeyString = decryptAESKey(encryptedAESKeyString, privateKey);
System.out.println("Decrypted AES key with RSA "+decryptedAESKeyString);
// Now decrypt data using the decrypted AES key!
String decryptedText = decryptTextUsingAES(encryptedText, decryptedAESKeyString);
//Showing all the outputs
System.out.println("input: " + encryptedText);
System.out.println("AES Key: " + secretAESKeyString);
System.out.println("decrypted: " + decryptedText);
System.out.println("Text New:" + textNew);
System.out.println("Encrypted New:" + encryptedTextNew);
//System.out.println("Decrypted New:" + decryptedTextNew);
}
// Create a new AES key. Uses 128 bit (weak)
public static String getSecretAESKeyAsString() throws Exception {
KeyGenerator generator = KeyGenerator.getInstance("AES");
generator.init(128); // The AES key size in number of bits
SecretKey secKey = generator.generateKey();
String encodedKey = Base64.getEncoder().encodeToString(secKey.getEncoded());
return encodedKey;
}
// Encrypt text using AES key
public static String encryptTextUsingAES(String plainText, String aesKeyString) throws Exception {
byte[] decodedKey = Base64.getDecoder().decode(aesKeyString);
SecretKey originalKey = new SecretKeySpec(decodedKey, 0, decodedKey.length, "AES");
// AES defaults to AES/ECB/PKCS5Padding in Java 7
Cipher aesCipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
aesCipher.init(Cipher.ENCRYPT_MODE, originalKey);
byte[] byteCipherText = aesCipher.doFinal(plainText.getBytes());
return Base64.getEncoder().encodeToString(byteCipherText);
}
// Decrypt text using AES key
public static String decryptTextUsingAES(String encryptedText, String aesKeyString) throws Exception {
byte[] decodedKey = Base64.getDecoder().decode(aesKeyString);
SecretKey originalKey = new SecretKeySpec(decodedKey, 0, decodedKey.length, "AES");
// AES defaults to AES/ECB/PKCS5Padding in Java 7
Cipher aesCipher = Cipher.getInstance("AES");
aesCipher.init(Cipher.DECRYPT_MODE, originalKey);
byte[] bytePlainText = aesCipher.doFinal(Base64.getDecoder().decode(encryptedText));
return new String(bytePlainText);
}
// Encrypt AES Key using RSA private key
private static byte[] encryptAESKey(String plainAESKey, Key publicKey ) throws Exception {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
return Base64.getEncoder().encode(cipher.doFinal(plainAESKey.getBytes()));
}
// Decrypt AES Key using RSA public key
private static String decryptAESKey(byte[] encryptedAESKey, Key privateKey) throws Exception {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
return new String(cipher.doFinal(Base64.getDecoder().decode(encryptedAESKey)));
}
//Getting public and private .jks format key
public static Key getPrivate(String filename) throws Exception {
String password = "123456";
FileInputStream is = new FileInputStream(filename);
KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
keystore.load(is, password.toCharArray());
String alias = "rib_pub_priv_ob";
Key key = keystore.getKey(alias, password.toCharArray());
return key;
}
// https://docs.oracle.com/javase/8/docs/api/java/security/spec/X509EncodedKeySpec.html
public static Key getPublic(String filename) throws Exception {
String password = "123456";
FileInputStream is = new FileInputStream(filename);
KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
keystore.load(is, password.toCharArray());
String alias = "tmsx_pub_priv_ob";
Key key = keystore.getKey(alias, password.toCharArray());
return key;
}
}
//Following is the output
Private key success
Private key :sun.security.rsa.RSAPrivateCrtKeyImpl#ffd2dcac
Public key success
Public key :sun.security.rsa.RSAPrivateCrtKeyImpl#fff19d78
Secret Key XsZue3ATt4OAQFP5C4sa8Q==
Encrypted text mjynBmIDhsj9L3jhFmzb4CFaJr+i5k2B1luuTdg0ls3NoAvI3wLfeU54Sxo7IDBrqH3i3F3RNM4DDPhWdbtEMNQ+27EcQOugidB2BcTFigzIImNohZOVjBi+qrPC7KWGLf9JWlJHUsoUz+oKiuAJGjitrrIMg/qQN7He87hH6hxfNZ7vceZV2N6HihYsQ4R1S6YFRUDVBwuG+IjvEyzihkw4mmlmjq4FIspXmaYuxYE/6urevUD/dY7HSLVrVRst83VRKnqDrzf32RolGsM12Ebyk0XJGGOYHV/OWfYExkaQdfUaEVMhU3h/tTmSoVJHEHTf1YdMxv5x/HZd2aXoYw==
Encrypted AES key with RSA [B#5f150435
Exception in thread "main" javax.crypto.BadPaddingException: Decryption error
at sun.security.rsa.RSAPadding.unpadV15(RSAPadding.java:380)
at sun.security.rsa.RSAPadding.unpad(RSAPadding.java:291)
at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:363)
at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:389)
at javax.crypto.Cipher.doFinal(Cipher.java:2165)
at demo123.AESwithRSA.decryptAESKey(AESwithRSA.java:135)
at demo123.AESwithRSA.main(AESwithRSA.java:60)

The error is caused by loading in getPublic the private key instead of the public key. This can be easily seen in the output: For both keys, objects of the type sun.security.rsa.RSAPrivateCrtKeyImpl are displayed, whereas the public key should actually be of the type sun.security.rsa.RSAPublicKeyImpl. To load the public key in getPublic replace the line
Key key = keystore.getKey(alias, password.toCharArray());
by
Key key = keystore.getCertificate(alias).getPublicKey();
See also [1][2]. With this fix the code works on my machine.
Update: In the current code, the Base64-encoded AES key (from getSecretAESKey) is encrypted with RSA and this key is then again Base64-encoded (in encryptAESKey). Such a double Base64-encoding is actually not necessary, as it would be sufficient to encrypt the raw AES key with RSA, as each Base64-encoding has a 33% overhead.

How can I have the java ciper algorithm and ruby cipher algorithm in sync?

I have this code in my rails app:
require 'openssl'
require 'digest/sha1'
require 'base64'
KEY="secret_key"
data = "secret message"
def encrypt_value(data)
cipher = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
cipher.encrypt
cipher.key = Digest::SHA256.digest(KEY)
encrypted = cipher.update(data)+cipher.final
return encrypted
end
def decrypt_value1(data)
cipher = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
cipher.decrypt
cipher.key = Digest::SHA256.digest(KEY)
decrypted = cipher.update(data)+cipher.final
data = Base64.decode64(decrypted)
return data
end
And java code:
import java.security.AlgorithmParameters;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;
public class EncryptionDecryption {
private static String salt;
private static int iterations = 65536 ;
private static int keySize = 256;
private static byte[] ivBytes;
// private static SecretKey secretKey;
private static final byte[] secretKey = "secret_key".getBytes();
public static void main(String []args) throws Exception {
salt = getSalt();
char[] message = "secret message".toCharArray();
System.out.println("Message: " + String.valueOf(message));
System.out.println("Encrypted: " + encrypt(message));
System.out.println("Decrypted: " + decrypt(encrypt(message).toCharArray()));
}
public static String encrypt(char[] plaintext) throws Exception {
byte[] saltBytes = salt.getBytes();
SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
PBEKeySpec spec = new PBEKeySpec(plaintext, saltBytes, iterations, keySize);
//secretKey = skf.generateSecret(spec);
SecretKeySpec secretSpec = new SecretKeySpec(secretKey, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secretSpec);
AlgorithmParameters params = cipher.getParameters();
ivBytes = params.getParameterSpec(IvParameterSpec.class).getIV();
byte[] encryptedTextBytes = cipher.doFinal(String.valueOf(plaintext).getBytes("UTF-8"));
return DatatypeConverter.printBase64Binary(encryptedTextBytes);
}
public static String decrypt(char[] encryptedText) throws Exception {
System.out.println(encryptedText);
byte[] encryptedTextBytes = DatatypeConverter.parseBase64Binary(new String(encryptedText));
SecretKeySpec secretSpec = new SecretKeySpec(secretKey, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secretSpec, new IvParameterSpec(ivBytes));
byte[] decryptedTextBytes = null;
try {
decryptedTextBytes = cipher.doFinal(encryptedTextBytes);
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
return new String(decryptedTextBytes);
}
public static String getSalt() throws Exception {
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
byte[] salt = new byte[20];
sr.nextBytes(salt);
return new String(salt);
}
}
How can I have both of them work with each other, for example if I send an encrypted data to java app from rails app it should be able to decode it and vice-versa.

As far as you are using the same cypher algorithms and message padding characters, they should work just fine.
Also, it is better to use some key exchange protocol, like Diffie-Hellman. Both Ruby's OpenSSL wrapper and Java's Crypto lib support it. It is a safer way to generate per session keys.
PS. Your code as you have it, seems to be written for a standalone execution. For example, your Java code for decoding assumes that your string was encoded with the same instance's encode method. Because, your decode method is using IV that was initialized in encode method (ivBytes).

Hybrid RSA-AES encryption

i try to create hybrid encryption using RSA-AES but for now i face a problem in this coding. From this code i try to Creating an RSA key pair , private and public key. After that i should Generating a random key symmetrical algorithm AES then i have to create an AES cipher in order to encrypt a text string with the AES key. Then after the text is encrypted with the AES key, then the AES key needs to be encrypted with the RSA public key and the encrypted AES key needs to be decrypted with the RSA private key. And finally decrypt the text message entered with AES key in order to read the message. I think i missing something in my coding. Please help me guys.
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Security;
import java.security.spec.EncodedKeySpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
public class HybridAesRsa
{
private Cipher cipher;
// RSA keys will be generated when the client and server connect
private PrivateKey myPrivateKey;
private byte[] myPublicKey;
private byte[] interlocutorPublicKey = null;
// Strings are encoded / decoded in BASE64
private BASE64Decoder b64decoder = new BASE64Decoder();
private BASE64Encoder b64encoder = new BASE64Encoder();
public HybridAesRsa()
{
try
{
cipher = Cipher.getInstance("RSA");
Security.addProvider(new BouncyCastleProvider());
}
catch (Exception ex){
Logger.getLogger(HybridAesRsa.class.getName()).log(Level.SEVERE,null,ex);
}
}
// Generate the pair of public and private keys using 1024 bytes
public KeyPair generateKey() throws Exception
{
KeyPair keyPair = null;
try{
//generate RSA key pair
KeyPairGenerator rsaKeyGen = KeyPairGenerator.getInstance("RSA");
rsaKeyGen.initialize(1024);
keyPair = rsaKeyGen.generateKeyPair();
//RSA public and private key
PublicKey publicKey = keyPair.getPublic();
PrivateKey privateKey = keyPair.getPrivate();
//System.out.println("RSA public key 1 ---> "+publicKey);
//System.out.println("RSA private key 1 ---> " +privateKey);
//for Chatting
myPublicKey = publicKey.getEncoded();
setMyPrivateKey(privateKey);
//Generating a random key symmetrical algorithm AES
KeyGenerator aesKeyGenerator = KeyGenerator.getInstance("AES");
SecureRandom random = new SecureRandom();
aesKeyGenerator.init(random);
SecretKey aesSecretKey = aesKeyGenerator.generateKey();
/*//The key is presented in a byte array
byte[] symmetricKey = aesSecretKey.getEncoded();
//Printing out the generated key
System.out.println("\nAES symmetric key --> " + symmetricKey); */
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(HybridAesRsa.class.getName()).log(Level.SEVERE,null,ex);
}
return keyPair;
}
// Encrypts text using public key
public String encrypt(String text, PublicKey publicKey, SecretKey aesSecretKey ) throws Exception
{
//Creating an AES cipher in order to encrypt a text string with the AES key
Cipher aesCipher = Cipher.getInstance("AES");
aesCipher.init(Cipher.ENCRYPT_MODE, aesSecretKey);
//Now that the text is encrypted with the AES key, then the AES key needs to be encrypted with the RSA public key
Cipher rsaCipher = Cipher.getInstance("RSA");
rsaCipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] encryptedAESkey = rsaCipher.doFinal(aesSecretKey.getEncoded());
//Printing out the encrypted AES key
System.out.println("\nAES key encrypted with RSA --> " + encryptedAESkey);
return text;
}
// Use the public key to encrypt the interlocutor
public String encrypt(String text) throws Exception
{
return encrypt(text, bytesToPublicKey(interlocutorPublicKey), null);
}
// Decrypts text using private key
public String decrypt(String text, PrivateKey privatekey) throws Exception
{
// Now the encrypted AES key needs to be decrypted with the RSA private key
Cipher rsaCipher2 = Cipher.getInstance("RSA");
rsaCipher2.init(Cipher.DECRYPT_MODE, privatekey);
byte[] encryptedAESkey = null;
byte[] decryptedAESkey = rsaCipher2.doFinal(encryptedAESkey);
//Print out the decrypted AES key
System.out.println("AES key decrypted with RSA private key --> " + decryptedAESkey);
//And finally decrypt the text message entered with AES key in order to read the message.
Cipher aesCipher2 = Cipher.getInstance("AES");
Key aesSecretKey = null;
aesCipher2.init(Cipher.DECRYPT_MODE,aesSecretKey);
byte[] encrypt = null;
byte [] decrypt = aesCipher2.doFinal(encrypt);
return text;
}
// Use my private key to decrypt
public String decrypt(String text) throws Exception
{
return decrypt(text, myPrivateKey);
}
// Public Key the caller is sent in byte [ ] and converted into a PublicKey object
public static PublicKey bytesToPublicKey(byte[] publicKeybytes)
{
PublicKey publicKey = null;
try {
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(publicKeybytes);
publicKey = keyFactory.generatePublic(publicKeySpec);
}
catch (InvalidKeySpecException ex) {
Logger.getLogger(HybridAesRsa.class.getName()).log(Level.SEVERE, null, ex);
}
catch (NoSuchAlgorithmException ex){
Logger.getLogger(HybridAesRsa.class.getName()).log(Level.SEVERE, null, ex);
}
return publicKey;
}
// Test
public static void main(String[] args){
try {
HybridAesRsa crypto = new HybridAesRsa();
KeyPair keyPair = crypto.generateKey();
PublicKey publicKey = keyPair.getPublic();
PrivateKey privateKey = keyPair.getPrivate();
KeyGenerator aesKeyGenerator = KeyGenerator.getInstance("AES");
SecretKey aesSecretKey = aesKeyGenerator.generateKey();
byte[] publicKeyBytes = publicKey.getEncoded();
byte[] privateKeyBytes = privateKey.getEncoded();
byte[] symmetricKey = aesSecretKey.getEncoded();
System.out.println("RSA Public key: " + new BigInteger(publicKeyBytes));
System.out.println("RSA Private key: " + new BigInteger(privateKeyBytes));
System.out.println("AES symmetric key --> " + new BigInteger(symmetricKey));
Cipher aesCipher = Cipher.getInstance("AES");
aesCipher.init(Cipher.ENCRYPT_MODE, aesSecretKey);
String testeMsg = "As a seed knows how to make a flower ? I love you.";
byte[] encrypt = aesCipher.doFinal(testeMsg.getBytes());
Cipher rsaCipher = Cipher.getInstance("RSA");
rsaCipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] encryptedAESkey = rsaCipher.doFinal(aesSecretKey.getEncoded());
String encrypted = crypto.encrypt(testeMsg, bytesToPublicKey(publicKeyBytes), aesSecretKey);
System.out.println("Encrypted Text: " + encrypted);
String decrypted = crypto.decrypt(encrypted, keyPair.getPrivate());
System.out.println("Decrypted Text: " + decrypted);
}
catch (Exception ex)
{
Logger.getLogger(HybridAesRsa.class.getName()).log(Level.SEVERE, null, ex);
}
}
public byte[] getMyPublicKey(){
return myPublicKey;
}
public void setMyPublicKey(byte[] myPublicKey) {
this.myPublicKey = myPublicKey;
}
public PrivateKey getMyPrivateKey(){
return myPrivateKey;
}
public byte[] getInterlocutorPublicKey(){
return interlocutorPublicKey;
}
public boolean hasInterlocutorPublicKey(){
return interlocutorPublicKey!=null;
}
public void setInterlocutorPublicKey(byte[] interlocutorPublicKey){
this.interlocutorPublicKey = interlocutorPublicKey;
}
public void setMyPrivateKey(PrivateKey aMyPrivateKey){
myPrivateKey = aMyPrivateKey;
}
}
Here the error for this code
Jun 19, 2016 5:50:14 PM HybridAesRsa main
SEVERE: null
java.lang.IllegalArgumentException: Null input buffer
at javax.crypto.Cipher.doFinal(Cipher.java:2117)
at HybridAesRsa.decrypt(HybridAesRsa.java:125)
at HybridAesRsa.main(HybridAesRsa.java:204)

You have this code:
byte[] encrypt = null;
byte [] decrypt = aesCipher2.doFinal(encrypt);
where you try to encrypt with a buffer that's initialised to null .. that is not possible.
The exception is quite clear:
java.lang.IllegalArgumentException: Null input buffer

AES-256 Password Based Encryption/Decryption in Java

I found a guide for implementing AES encryption/decryption in Java and tried to understand each line as I put it into my own solution. However, I don't fully understand it and am having issues as a result. The end goal is to have passphrase based encryption/decryption. I've read other articles/stackoverflow posts about this, but most do not provide enough explanation (I am very new to crypto in Java)
My main issues right now are that even when I set byte[] saltBytes = "Hello".getBytes();
I still get a different Base64 result in the end (char[] password is random each time, but I read that it is safer to leave passwords in char[] form. My other problem is that when the program gets to decrypt(), I get a NullPointerException at
byte[] saltBytes = salt.getBytes("UTF-8");
Thank you in advance for any help/advice you can give me.
The code in question:
import java.security.AlgorithmParameters;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;
public class EncryptionDecryption {
private static String salt;
private static int iterations = 65536 ;
private static int keySize = 256;
private static byte[] ivBytes;
public static void main(String []args) throws Exception {
char[] message = "PasswordToEncrypt".toCharArray();
System.out.println("Message: " + message.toString());
System.out.println("Encrypted: " + encrypt(message));
System.out.println("Decrypted: " + decrypt(encrypt(message).toCharArray()));
}
public static String encrypt(char[] plaintext) throws Exception {
salt = getSalt();
byte[] saltBytes = salt.getBytes();
SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
PBEKeySpec spec = new PBEKeySpec(plaintext, saltBytes, iterations, keySize);
SecretKey secretKey = skf.generateSecret(spec);
SecretKeySpec secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secretSpec);
AlgorithmParameters params = cipher.getParameters();
ivBytes = params.getParameterSpec(IvParameterSpec.class).getIV();
byte[] encryptedTextBytes = cipher.doFinal(plaintext.toString().getBytes("UTF-8"));
return DatatypeConverter.printBase64Binary(encryptedTextBytes);
}
public static String decrypt(char[] encryptedText) throws Exception {
byte[] saltBytes = salt.getBytes("UTF-8");
byte[] encryptedTextBytes = DatatypeConverter.parseBase64Binary(encryptedText.toString());
SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
PBEKeySpec spec = new PBEKeySpec(encryptedText, saltBytes, iterations, keySize);
SecretKey secretkey = skf.generateSecret(spec);
SecretKeySpec secretSpec = new SecretKeySpec(secretkey.getEncoded(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secretSpec, new IvParameterSpec(ivBytes));
byte[] decryptedTextBytes = null;
try {
decryptedTextBytes = cipher.doFinal(encryptedTextBytes);
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
return decryptedTextBytes.toString();
}
public static String getSalt() throws Exception {
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
byte[] salt = new byte[20];
sr.nextBytes(salt);
return salt.toString();
}
}

I think that you are making two mistakes :)
I've corrected your sample code to make it work :
import java.security.AlgorithmParameters;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;
public class EncryptionDecryption {
private static String salt;
private static int iterations = 65536 ;
private static int keySize = 256;
private static byte[] ivBytes;
private static SecretKey secretKey;
public static void main(String []args) throws Exception {
salt = getSalt();
char[] message = "PasswordToEncrypt".toCharArray();
System.out.println("Message: " + String.valueOf(message));
System.out.println("Encrypted: " + encrypt(message));
System.out.println("Decrypted: " + decrypt(encrypt(message).toCharArray()));
}
public static String encrypt(char[] plaintext) throws Exception {
byte[] saltBytes = salt.getBytes();
SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
PBEKeySpec spec = new PBEKeySpec(plaintext, saltBytes, iterations, keySize);
secretKey = skf.generateSecret(spec);
SecretKeySpec secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secretSpec);
AlgorithmParameters params = cipher.getParameters();
ivBytes = params.getParameterSpec(IvParameterSpec.class).getIV();
byte[] encryptedTextBytes = cipher.doFinal(String.valueOf(plaintext).getBytes("UTF-8"));
return DatatypeConverter.printBase64Binary(encryptedTextBytes);
}
public static String decrypt(char[] encryptedText) throws Exception {
System.out.println(encryptedText);
byte[] encryptedTextBytes = DatatypeConverter.parseBase64Binary(new String(encryptedText));
SecretKeySpec secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secretSpec, new IvParameterSpec(ivBytes));
byte[] decryptedTextBytes = null;
try {
decryptedTextBytes = cipher.doFinal(encryptedTextBytes);
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
return new String(decryptedTextBytes);
}
public static String getSalt() throws Exception {
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
byte[] salt = new byte[20];
sr.nextBytes(salt);
return new String(salt);
}
}
The first mistake is that you generate 2 different salts (when using the encrypt method), so encrypted/decrypted logs were differents (logical, but the decryption would still work because you are calling the decryption directly after encryption).
The second mistake was for the secret key. You need to generate a secret key when you are encrypting, but not decrypting. To put it more simply, it is as if i was encrypting with the password "encrypt" and that you are trying to decrypt it with the password "decrypt".
I would advise you to generate every random stuff (such as private key, salt etc on startup). But beware that when you'll stop your app, you won't be able to decrypt old stuff unless getting the exact same random stuff.
Hope I helped :)
Regards,

Encrypt Decrypt my own key not generated java

I am new to cryptography, so I have a question:
How can I create my own key (let`s say like a string "1234"). Because I need to encrypt a string with a key (defined by me), save the encrypted string in a database and when I want to use it, take it from the database and decrypt it with the key known by me.
I have this code :
import java.security.InvalidKeyException;
import java.security.*;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
public class LocalEncrypter {
private static String algorithm = "PBEWithMD5AndDES";
//private static Key key = null;
private static Cipher cipher = null;
private static SecretKey key;
private static void setUp() throws Exception {
///key = KeyGenerator.getInstance(algorithm).generateKey();
SecretKeyFactory factory = SecretKeyFactory.getInstance(algorithm);
String pass1 = "thisIsTheSecretKeyProvidedByMe";
byte[] pass = pass1.getBytes();
SecretKey key = factory.generateSecret(new DESedeKeySpec(pass));
cipher = Cipher.getInstance(algorithm);
}
public static void main(String[] args)
throws Exception {
setUp();
byte[] encryptionBytes = null;
String input = "1234";
System.out.println("Entered: " + input);
encryptionBytes = encrypt(input);
System.out.println(
"Recovered: " + decrypt(encryptionBytes));
}
private static byte[] encrypt(String input)
throws InvalidKeyException,
BadPaddingException,
IllegalBlockSizeException {
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] inputBytes = input.getBytes();
return cipher.doFinal(inputBytes);
}
private static String decrypt(byte[] encryptionBytes)
throws InvalidKeyException,
BadPaddingException,
IllegalBlockSizeException {
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] recoveredBytes =
cipher.doFinal(encryptionBytes);
String recovered =
new String(recoveredBytes);
return recovered;
}
}
Exception in thread "main" java.security.spec.InvalidKeySpecException: Invalid key spec
at com.sun.crypto.provider.PBEKeyFactory.engineGenerateSecret(PBEKeyFactory.java:114)
at javax.crypto.SecretKeyFactory.generateSecret(SecretKeyFactory.java:335)
at LocalEncrypter.setUp(LocalEncrypter.java:22)
at LocalEncrypter.main(LocalEncrypter.java:28)

A KeyGenerator generates random keys. Since you know the secret key, what you need is a SecretKeyFactory. Get an instance for your algorithm (DESede), and then call its generateSecret méthode with an instance of DESedeKeySpec as argument:
SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");
SecretKey key = factory.generateSecret(new DESedeKeySpec(someByteArrayContainingAtLeast24Bytes));
Here is a complete example that works. As I said, DESedeKeySpec must be used with the DESede algorithm. Using a DESede key with PBEWithMD5AndDES makes no sense.
public class EncryptionTest {
public static void main(String[] args) throws Exception {
byte[] keyBytes = "1234567890azertyuiopqsdf".getBytes("ASCII");
DESedeKeySpec keySpec = new DESedeKeySpec(keyBytes);
SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");
SecretKey key = factory.generateSecret(keySpec);
byte[] text = "Hello world".getBytes("ASCII");
Cipher cipher = Cipher.getInstance("DESede");
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] encrypted = cipher.doFinal(text);
cipher = Cipher.getInstance("DESede");
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] decrypted = cipher.doFinal(encrypted);
System.out.println(new String(decrypted, "ASCII"));
}
}

Well, I found the solution after combining from here and there. The encrypted result will be formatted as Base64 String for safe saving as xml file.
package cmdCrypto;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import javax.xml.bind.DatatypeConverter;
public class CmdCrypto {
public static void main(String[] args) {
try{
final String strPassPhrase = "123456789012345678901234"; //min 24 chars
String param = "No body can see me";
System.out.println("Text : " + param);
SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");
SecretKey key = factory.generateSecret(new DESedeKeySpec(strPassPhrase.getBytes()));
Cipher cipher = Cipher.getInstance("DESede");
cipher.init(Cipher.ENCRYPT_MODE, key);
String str = DatatypeConverter.printBase64Binary(cipher.doFinal(param.getBytes()));
System.out.println("Text Encryted : " + str);
cipher.init(Cipher.DECRYPT_MODE, key);
String str2 = new String(cipher.doFinal(DatatypeConverter.parseBase64Binary(str)));
System.out.println("Text Decryted : " + str2);
} catch(Exception e) {
e.printStackTrace();
}
}
}