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Getting Key must be 128, 192, or 256 bit long twofish

Following code is written to encrypt the plain text, I am using IAIK Twofish encryption/decryption code in java below sample code works fine with 128 bit key but when i try it with 192 and 156 bit key it gives an exception that Key must be 128, 192, or 256 bit long!

private static void doCrypto(int cipherMode, String key, File inputFile, File outputFile) throws CryptoException {
        try {
            SecretKey secretKey = new SecretKeySpec(key.getBytes(), ALGORITHM);
            Cipher cipher = Cipher.getInstance(TRANSFORMATION, "IAIK");
            cipher.init(cipherMode, secretKey); 
            FileInputStream inputStream = new FileInputStream(inputFile);
            byte[] inputBytes = new byte[(int) inputFile.length()];
            byte[] outputBytes = cipher.doFinal(inputBytes);
            FileOutputStream outputStream = new FileOutputStream(outputFile);
        } catch (NoSuchPaddingException | NoSuchAlgorithmException | InvalidKeyException | BadPaddingException
                | IllegalBlockSizeException | IOException ex) {
            throw new CryptoException("Error encrypting/decrypting file", ex);
        } catch (NoSuchProviderException e) {
            // TODO Auto-generated catch block

for above method when I am giving 128 bit key it works fine as below,

    KeyGenerator keyGen = KeyGenerator.getInstance("Twofish", "IAIK");
    SekertKey key = key.generateKey();
    encrypt(txtSecretKey.getText(), inputFile, encryptedFile);
Caused by: Key must be 128, 192, or 256 bit long!
    at Source)
    at Source)
    at Source)
    at javax.crypto.Cipher.init(
    at javax.crypto.Cipher.init(
    at com.opensourse.crypto.twofish.CryptoUtils.doCrypto(



In your main method you’re transforming the SecretKey to a String that is shown in a (GUI) textfield. Printing out the contents of the key looks like:

key in hex: 7b44a1f09136a248a40c8043fa02fbcf
textfield : 7B:44:A1:F0:91:36:A2:48:A4:0C:80:43:FA:02:FB:CF

Converting this String in the textfield back to a byte[] to regenerate the secretKey with “.getBytes” will fail as the colon chars will be decoded as well:

SecretKey secretKey = new SecretKeySpec(key.getBytes(), ALGORITHM)

The IAIK-Util-class provides a “.toByteArray” method that simply ignores other chars than ‘0-9’ and ‘a-f’, see the documentation in

Convert the given string with hex values to a byte array. For example “001122” is turned into {0, 0x11, 0x22}. All characters outside the range of ‘0’-‘9’, ‘a’-‘z’, and ‘A’-‘Z’ or simply ignored.

Simply change the line in doCrypto-method and all is working:

SecretKey secretKey = new SecretKeySpec(iaik.utils.Util.toByteArray(key), ALGORITHM);
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