Develop Reference

How to resolve Invalid key exception in java?

I am trying to encrypt a file and i am using the following:
public class AESFileEncryption {
public static void main(String[] args) throws Exception {
// file to be encrypted
FileInputStream inFile = new FileInputStream("plainfile.txt");
// encrypted file
FileOutputStream outFile = new FileOutputStream("encryptedfile.des");
// password to encrypt the file
String password = "javapapers";
// password, iv and salt should be transferred to the other end
// in a secure manner
// salt is used for encoding
// writing it to a file
// salt should be transferred to the recipient securely
// for decryption
byte[] salt = new byte[8];
SecureRandom secureRandom = new SecureRandom();
secureRandom.nextBytes(salt);
FileOutputStream saltOutFile = new FileOutputStream("salt.enc");
saltOutFile.write(salt);
saltOutFile.close();
SecretKeyFactory factory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
KeySpec keySpec = new PBEKeySpec(password.toCharArray(), salt, 65536,
256);
SecretKey secretKey = factory.generateSecret(keySpec);
SecretKey secret = new SecretKeySpec(secretKey.getEncoded(), "AES");
//
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secret);
AlgorithmParameters params = cipher.getParameters();
// iv adds randomness to the text and just makes the mechanism more
// secure
// used while initializing the cipher
// file to store the iv
FileOutputStream ivOutFile = new FileOutputStream("iv.enc");
byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
ivOutFile.write(iv);
ivOutFile.close();
//file encryption
byte[] input = new byte[64];
int bytesRead;
while ((bytesRead = inFile.read(input)) != -1) {
byte[] output = cipher.update(input, 0, bytesRead);
if (output != null)
outFile.write(output);
}
byte[] output = cipher.doFinal();
if (output != null)
outFile.write(output);
inFile.close();
outFile.flush();
outFile.close();
System.out.println("File Encrypted.");
}
}
but I am getting the following error:
Exception in thread "main" java.security.InvalidKeyException: Illegal key size or default parameters
Can someone please help?

Decrypting of AES/CBC/PKCS5Padding Error: Given final block not properly padded

I'm getting Given final block not properly padded error while decrypting AES/CBC/PKCS5Padding cipher on large encrypted file.
I think this issue is caused by adding wrong initialization vector in cipher.init() method.
I can't read whole file at runtime, so i need to encrypt fixed-size blocks. At this point I'm creating IV and storing it to .txt file. But in decrypting method I'm using the same IV every decryption cycle. How should I change this?
Encryption:
void encrypt() throws Exception{
char[] password = passwordText.getText().toCharArray();
byte[] salt = new byte[8];
/* Creating and saving salt */
salt = saveSalt(salt);
/* Securing password */
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
KeySpec spec = new PBEKeySpec(password, salt, 65536, 128);
SecretKey tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");
if (choosedFile != null) {
/* Choosing algorithm for decryption */
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
/* Getting plain file */
CipherInputStream fis = new CipherInputStream(new FileInputStream(choosedFile), cipher);
CipherOutputStream fos = new CipherOutputStream(new FileOutputStream(choosedFile+".encrypted"), cipher);
/* Encrypting and Measuring */
long startTime = System.currentTimeMillis();
cipher.init(Cipher.ENCRYPT_MODE, secret);
byte[] rawText = new byte[128];
int count;
while((count = fis.read(rawText)) > 0) {
System.out.println(count);
byte[] encryptedText = cipher.doFinal(rawText);
fos.write(encryptedText, 0, count);
}
long stopTime = System.currentTimeMillis();
fis.close();
fos.close();
/* Creating initialization vector and storing*/
byte[] iVector = cipher.getIV();
saveIVector(iVector);
text.setText(text.getText() + "File was encrypted in " + (stopTime - startTime) + "ms.\n");
}
}
Decryption:
void decrypt() throws Exception {
/* Getting salt */
byte[] salt = getSalt();
/* Getting initialization vector */
byte[] iVector = getIVector();
/* Getting user password */
char[] password = passwordText.getText().toCharArray();
/* Securing password */
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
KeySpec spec = new PBEKeySpec(password, salt, 65536, 128);
SecretKey tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");
if (choosedFile != null) {
/* Choosing algorithm for decryption */
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
/* Getting ciphered file */
CipherInputStream fis = new CipherInputStream(new FileInputStream(choosedFile), cipher);
CipherOutputStream fos = new CipherOutputStream(new FileOutputStream(choosedFile+".decrypted"), cipher);
/* Decrypting and Measuring */
long startTime = System.currentTimeMillis();
cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iVector));
byte[] rawText = new byte[128];
int count;
while((count = fis.read(rawText)) > 0) {
byte[] encryptedText = cipher.doFinal(rawText);
fos.write(encryptedText, 0, count);
}
long stopTime = System.currentTimeMillis();
fis.close();
fos.close();

When using CipherInputStream and CipherOutputStream, the streams handle all the calls to the cipher (that's why you pass the cipher to it on initialization). You just need to initialize it correctly, and stream the data through the stream, and the cipher stream will do the needed calls to update() and doFinal(). Remember to close the steams to trigger the doFinal().
Currently your code passes the data through the cipher several times in an uncontrolled way, and the data is messed up.
Also, you only need a CipherInputStream for decrypt, and a CipherOutputStream for encrypt. In your current code you use both for both encrypt and decrypt.
Encrypt could be something like this (this don't handle the iv ..):
...
cipher.init(Cipher.ENCRYPT_MODE, secret);
InputStream is = new FileInputStream(choosedFile);
OutputStream os = new CipherOutputStream(new FileOutputStream(choosedFile+".encrypted"), cipher);
byte[] buffer = new byte[1024];
int len;
while ((len = is.read(buffer)) != -1) {
os.write(buffer, 0, len);
}
is.close();
os.close();
...

Worried about "until I had to cut large file into fixed-size blocks".
Using "chunk" in place of "block" above because "block"has a specific meaning in block ciphers such as AES.
What are toy doing with the chunks, concatenating them?
With CBC mode, after the first block the the previous encrypted block value is effectively used as the IV for the next block. So when splitting and then concatenating the chunks the value of the last block of the previous chunk is the IV for the next chunk.
See CBC mode.
Or are you doing something completely different?

incomplete RSA decryption with large XML file type - JAVA

I have a problem when decrypting XML type my file my returns incomplete data algorithm and rare symbols.
public File decryptFile(File fileInput, X509Certificate certificate) throws BadPaddingException, Exception {
try (DataInputStream dis = new DataInputStream(new FileInputStream(fileInput))) {
byte[] encryptedKeyBytes = new byte[dis.readInt()];
dis.readFully(encryptedKeyBytes);
PublicKey publicKey = certificate.getPublicKey();
rsaCipher.init(Cipher.DECRYPT_MODE, publicKey);
byte[] rijndaelKeyBytes = rsaCipher.doFinal(encryptedKeyBytes);
SecretKey rijndaelKey = new SecretKeySpec(rijndaelKeyBytes, "Rijndael");
byte[] iv = new byte[16];
dis.read(iv);
IvParameterSpec spec = new IvParameterSpec(iv);
Cipher cipher = Cipher.getInstance("Rijndael/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, rijndaelKey, spec);
try (CipherInputStream cis = new CipherInputStream(dis, cipher)) {
try (FileOutputStream fos = new FileOutputStream(fileInput.getAbsolutePath() + ".xml")) {
byte[] data = new byte[16];
int theByte;
while ((theByte = cis.read(data)) != -1) {
System.out.print(new String(data));
fos.write(data, 0, theByte);
}
System.out.println("\n\n");
}
}
}
return new File(fileInput.getAbsolutePath() + ".xml");
}
this code returns me the data
</ctaAbonBenef><distPago>00000</distPago><item>00000</item><pagoPoder>N</p�|���[�[W�Z�5��Q�
I think this has to do with UTF-8, but I can not solve.
Now I can also believe that it is the encryption algorithm to use, I leave just in case.
public static void generateFileEncrypt(File fileInput, PrivateKey privateKey, String folderSave) throws Exception {
String fileOutput = folderSave + "\" + fileInput.getName() + ENCRYPTED_FILENAME_SUFFIX;
DataOutputStream output = new DataOutputStream(new FileOutputStream(fileOutput));
Cipher rsaCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
rsaCipher.init(Cipher.ENCRYPT_MODE, privateKey);
KeyGenerator rijndaelKeyGenerator = KeyGenerator.getInstance("Rijndael");
rijndaelKeyGenerator.init(128);
Key rijndaelKey = rijndaelKeyGenerator.generateKey();
byte[] encodedKeyBytes = rsaCipher.doFinal(rijndaelKey.getEncoded());
output.writeInt(encodedKeyBytes.length);
output.write(encodedKeyBytes);
SecureRandom random = new SecureRandom();
byte[] iv = new byte[16];
random.nextBytes(iv);
output.write(iv);
IvParameterSpec spec = new IvParameterSpec(iv);
Cipher symmetricCipher = Cipher.getInstance("Rijndael/CBC/PKCS5Padding");
symmetricCipher.init(Cipher.ENCRYPT_MODE, rijndaelKey, spec);
try (
CipherOutputStream cos = new CipherOutputStream(output, symmetricCipher);
FileInputStream fis = new FileInputStream(fileInput)) {
int theByte;
byte[] data = new byte[16];
while ((theByte = fis.read(data)) != -1) {
System.out.print(new String(data));
cos.write(data, 0, theByte);
}
System.out.println("\n\n");
cos.flush();
}
}
Thanks in advance.

I haven't digested all your code; I stopped when I saw you trying to decrypt with the public key, and encrypting with the private key. That's sort of like a digital signature, but your padding will be all wrong and you should use the Signature class if that is what your really want to do.
The public key is used to encrypt, or to verify a digital signature. Use the private key to decrypt, and see if that resolves your problem.
You are still doing it wrong. Don't call it "encryption" if the key isn't private.
But anyway, I think the printing to stdout looks wrong because you are converting the entire buffer to text. The last block is likely to be padded, so it won't decode to valid text—it's padding; it wasn't part of the input file, and you aren't writing it to the decrypted file, but you are printing it.
Change to encrypt with the public key, decrypt with the private key, and then change your printing to this:
System.out.print(new String(data, 0, theByte));
Even better would be to specify the character set of the data (probably UTF-8, since it's the default for XML).

I think u should do the opposite. encrypt with the public key and decrypt with the private key..

cipher.getInstance() with blowfish in java

Hello My code does not give me any error but also does not work.
I do not know what it is problem but I think it is in Cipher.getInstance
private static void createKey(char[] password) throws Exception {
System.out.println("Generating a Blowfish key...");
// Create a blowfish key
KeyGenerator keyGenerator = KeyGenerator.getInstance("Blowfish");
keyGenerator.init(256);
Key key = keyGenerator.generateKey();
System.out.println("Done generating the key.");
// Now we need to create the file with the key,
// encrypting it with a password.
byte[] salt = new byte[8];
SecureRandom random = new SecureRandom();
random.nextBytes(salt);
PBEKeySpec pbeKeySpec = new PBEKeySpec(password);
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithSHAAndTwofish-CBC");
SecretKey pbeKey = keyFactory.generateSecret(pbeKeySpec);
PBEParameterSpec pbeParamSpec = new PBEParameterSpec(salt, ITERATIONS);
//Cipher cipher = Cipher.getInstance("PBEWithMD5AndDES-CBC");
//Cipher cipher = Cipher.getInstance("PBEWithSHAAndTwofish-CBC");
Cipher cipher = Cipher.getInstance("PBEWithSHAAndTwofish-CBC");
cipher.init(Cipher.ENCRYPT_MODE, pbeKey, pbeParamSpec);
// Encrypt the key
byte[] encryptedKeyBytes = cipher.doFinal(key.getEncoded());
// Write out the salt, and then the encrypted key bytes
FileOutputStream fos = new FileOutputStream(KEY_FILENAME);
fos.write(salt);
fos.write(encryptedKeyBytes);
fos.close();
}

RSA encryption in Android

I am writing a program which employs RSA in Android. I have the following problem:
I am getting the RSA keys:
KeyPair kp = kpg.genKeyPair();
publicKey = kp.getPublic();
privateKey = kp.getPrivate();
Using the encryption function to encrypt a test string:
String test ="test";
byte[] testbytes = test.getBytes();
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] cipherData = cipher.doFinal(testbytes);
String s = new String(cipherData);
Log.d("testbytes after encryption",s);
In the decryption function i am decrypting the data back to get the original string
Cipher cipher2 = Cipher.getInstance("RSA");
cipher2.init(Cipher.DECRYPT_MODE, privateKey);
byte[] plainData = cipher.doFinal(cipherData);
String p = new String(plainData);
Log.d("decrypted data is:",p);
The data in 'p' printed out in the log does not match the original string "test" . Where am I going wrong in this?

Here an example on how to do it, BUT in practice,
You can't really encrypt and decrypt whole files with just RSA. The
RSA algorithm can only encrypt a single block, and it is rather slow
for doing a whole file.
You can encrypt the file using
3DES or AES, and then encrypt the AES key using intended recipient's
RSA public key.
Some code:
public static void main(String[] args) throws Exception {
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
kpg.initialize(1024);
KeyPair keyPair = kpg.generateKeyPair();
PrivateKey privKey = keyPair.getPrivate();
PublicKey pubKey = keyPair.getPublic();
// Encrypt
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
String test = "My test string";
String ciphertextFile = "ciphertextRSA.txt";
InputStream fis = new ByteArrayInputStream(test.getBytes("UTF-8"));
FileOutputStream fos = new FileOutputStream(ciphertextFile);
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
byte[] block = new byte[32];
int i;
while ((i = fis.read(block)) != -1) {
cos.write(block, 0, i);
}
cos.close();
// Decrypt
String cleartextAgainFile = "cleartextAgainRSA.txt";
cipher.init(Cipher.DECRYPT_MODE, privKey);
fis = new FileInputStream(ciphertextFile);
CipherInputStream cis = new CipherInputStream(fis, cipher);
fos = new FileOutputStream(cleartextAgainFile);
while ((i = cis.read(block)) != -1) {
fos.write(block, 0, i);
}
fos.close();
}