Example usage for javax.crypto Cipher doFinal

Introduction

In this page you can find the example usage for javax.crypto Cipher doFinal.

Prototype

public final int doFinal(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)
        throws ShortBufferException, IllegalBlockSizeException, BadPaddingException 

Source Link

Document

Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.

Usage

From source file:MainClass.java

public static void main(String[] args) throws Exception {
    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

    SecureRandom random = new SecureRandom();
    IvParameterSpec ivSpec = createCtrIvForAES();
    Key key = createKeyForAES(256, random);
    Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding", "BC");
    String input = "12345678";
    Mac mac = Mac.getInstance("DES", "BC");
    byte[] macKeyBytes = new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 };
    Key macKey = new SecretKeySpec(macKeyBytes, "DES");

    cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec);

    byte[] cipherText = new byte[cipher.getOutputSize(input.length() + mac.getMacLength())];

    int ctLength = cipher.update(input.getBytes(), 0, input.length(), cipherText, 0);

    mac.init(macKey);/*from ww  w.  j  ava 2  s.  c om*/
    mac.update(input.getBytes());

    ctLength += cipher.doFinal(mac.doFinal(), 0, mac.getMacLength(), cipherText, ctLength);

    cipher.init(Cipher.DECRYPT_MODE, key, ivSpec);

    byte[] plainText = cipher.doFinal(cipherText, 0, ctLength);
    int messageLength = plainText.length - mac.getMacLength();

    mac.init(macKey);
    mac.update(plainText, 0, messageLength);

    byte[] messageHash = new byte[mac.getMacLength()];
    System.arraycopy(plainText, messageLength, messageHash, 0, messageHash.length);

    System.out.println("plain : " + new String(plainText) + " verified: "
            + MessageDigest.isEqual(mac.doFinal(), messageHash));

}

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From source file:MainClass.java

public static void main(String[] args) throws Exception {
    Security.addProvider(new BouncyCastleProvider());
    SecureRandom random = new SecureRandom();
    IvParameterSpec ivSpec = createCtrIvForAES(1, random);
    Key key = createKeyForAES(256, random);
    Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding", "BC");
    String input = "www.java2s.com";
    Mac mac = Mac.getInstance("DES", "BC");
    byte[] macKeyBytes = "12345678".getBytes();
    Key macKey = new SecretKeySpec(macKeyBytes, "DES");
    System.out.println("input : " + input);

    // encryption step
    cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec);
    byte[] cipherText = new byte[cipher.getOutputSize(input.length() + mac.getMacLength())];
    int ctLength = cipher.update(input.getBytes(), 0, input.length(), cipherText, 0);
    mac.init(macKey);/* w w  w  .j  av a 2s  .  c o  m*/
    mac.update(input.getBytes());
    ctLength += cipher.doFinal(mac.doFinal(), 0, mac.getMacLength(), cipherText, ctLength);
    System.out.println("cipherText : " + new String(cipherText));

    // decryption step
    cipher.init(Cipher.DECRYPT_MODE, key, ivSpec);
    byte[] plainText = cipher.doFinal(cipherText, 0, ctLength);
    int messageLength = plainText.length - mac.getMacLength();

    mac.init(macKey);
    mac.update(plainText, 0, messageLength);

    byte[] messageHash = new byte[mac.getMacLength()];
    System.arraycopy(plainText, messageLength, messageHash, 0, messageHash.length);

    System.out.println("plain : " + new String(plainText) + " verified: "
            + MessageDigest.isEqual(mac.doFinal(), messageHash));
}

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From source file:Main.java

/**
 * Invokes the Cipher to perform encryption or decryption (depending on the
 * initialized mode)./*w ww. j a va2  s  .  c  o  m*/
 */
public static int doFinal(Cipher cipher, byte[] input, int inputOffSet, int inputLen, byte[] ouput,
        int outputOffSet) {
    try {
        return cipher.doFinal(input, inputOffSet, inputLen, ouput, outputOffSet);
    } catch (IllegalBlockSizeException e) {
        throw new IllegalStateException("Unable to invoke Cipher due to illegal block size", e);
    } catch (BadPaddingException e) {
        throw new IllegalStateException("Unable to invoke Cipher due to bad padding", e);
    } catch (ShortBufferException e) {
        throw new IllegalStateException("Short Buffer Exception", e);
    }
}

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