AES decryption in Java - IvParameterSpec to big
- by user1277269
Im going to decrypt a plaintext with two keys.
As you see in the picture were have one encrypted file wich contains KEY1(128 bytes),KEYIV(128 bytes),key2(128bytes) wich is not used in this case then we have the ciphertext.
The error I get here is "Exception in thread "main" java.security.InvalidAlgorithmParameterException: Wrong IV length: must be 16 bytes long.
but it is 64 bytes."
Picture: http://i264.photobucket.com/albums/ii200/XeniuM05/bg_zps0a523659.png
public class AES {
public static void main(String[] args) throws Exception {
byte[] encKey1 = new byte[128];
byte[] EncIV = new byte[256];
byte[] UnEncIV = new byte[128];
byte[] unCrypKey = new byte[128];
byte[] unCrypText = new byte[1424];
File f = new File("C://ftp//ciphertext.enc");
FileInputStream fis = new FileInputStream(F);
byte[] EncText = new byte[(int) f.length()];
fis.read(encKey1);
fis.read(EncIV);
fis.read(EncText);
EncIV = Arrays.copyOfRange(EncIV, 128, 256);
EncText = Arrays.copyOfRange(EncText, 384, EncText.length);
System.out.println(EncText.length);
KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
char[] password = "lab1StorePass".toCharArray();
java.io.FileInputStream fos = new java.io.FileInputStream(
"C://ftp//lab1Store");
ks.load(fos, password);
char[] passwordkey1 = "lab1KeyPass".toCharArray();
PrivateKey Lab1EncKey = (PrivateKey) ks.getKey("lab1EncKeys",
passwordkey1);
Cipher rsaDec = Cipher.getInstance("RSA"); // set cipher to RSA decryption
rsaDec.init(Cipher.DECRYPT_MODE, Lab1EncKey); // initalize cipher ti lab1key
unCrypKey = rsaDec.doFinal(encKey1); // Decryps first key
UnEncIV = rsaDec.doFinal(EncIV); //decryps encive byte array to undecrypted bytearray---- OBS! Error this is 64 BYTES big, we want 16?
System.out.println("lab1key "+ unCrypKey +" IV " + UnEncIV);
//-------CIPHERTEXT decryption---------
Cipher AESDec = Cipher.getInstance("AES/CBC/PKCS5Padding");
//---------convert decrypted bytearrays to acctual keys
SecretKeySpec unCrypKey1 = new SecretKeySpec(unCrypKey, "AES");
IvParameterSpec ivSpec = new IvParameterSpec(UnEncIV);
AESDec.init(Cipher.DECRYPT_MODE, unCrypKey1, ivSpec );
unCrypText = AESDec.doFinal(EncText);
// Convert decrypted cipher bytearray to string
String deCryptedString = new String(unCrypKey);
System.out.println(deCryptedString);
}
