Example usage for org.bouncycastle.crypto.engines XSalsa20Engine XSalsa20Engine

Introduction

In this page you can find the example usage for org.bouncycastle.crypto.engines XSalsa20Engine XSalsa20Engine.

Prototype

XSalsa20Engine

Source Link

Usage

From source file:com.github.capone.protocol.crypto.SymmetricKey.java

License:Open Source License

public byte[] encrypt(Nonce nonce, byte[] message) throws EncryptionException {
    try {/*from  w  w  w.j a v  a 2  s  .com*/
        byte[] subkey = new byte[SUBKEYBYTES];
        byte[] encrypted = new byte[message.length + MACBYTES];

        StreamCipher cipher = new XSalsa20Engine();
        cipher.init(true, new ParametersWithIV(key, nonce.nonce));
        cipher.processBytes(subkey, 0, subkey.length, subkey, 0);
        cipher.processBytes(message, 0, message.length, encrypted, MACBYTES);

        Mac auth = new Poly1305();
        auth.init(new KeyParameter(subkey));
        auth.update(encrypted, MACBYTES, message.length);
        auth.doFinal(encrypted, 0);

        return encrypted;
    } catch (Exception e) {
        throw new EncryptionException();
    }
}

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From source file:com.github.capone.protocol.crypto.SymmetricKey.java

License:Open Source License

public byte[] decrypt(Nonce nonce, byte[] encrypted) throws DecryptionException {
    byte[] subkey = new byte[SUBKEYBYTES];
    byte[] mac = new byte[MACBYTES];
    byte[] plain = new byte[encrypted.length - MACBYTES];

    if (encrypted.length < MACBYTES) {
        throw new DecryptionException();
    }//from   w  ww  . j ava  2 s. c  o  m

    StreamCipher cipher = new XSalsa20Engine();
    cipher.init(true, new ParametersWithIV(key, nonce.nonce));
    cipher.processBytes(subkey, 0, subkey.length, subkey, 0);

    Mac auth = new Poly1305();
    auth.init(new KeyParameter(subkey));
    auth.update(encrypted, MACBYTES, encrypted.length - MACBYTES);
    auth.doFinal(mac, 0);

    boolean validMac = true;
    for (int i = 0; i < MACBYTES; i++) {
        validMac &= mac[i] == encrypted[i];
    }
    if (!validMac) {
        throw new DecryptionException();
    }

    cipher.processBytes(encrypted, MACBYTES, encrypted.length - MACBYTES, plain, 0);

    return plain;
}

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