mangadex_at_home/src/main/java/mdnet/security/TweetNaclFast.java

// Copyright (c) 2014-present Tom Zhou<appnet.link@gmail.com>

package mdnet.security;

import java.io.UnsupportedEncodingException;
import java.security.SecureRandom;
import java.util.concurrent.atomic.AtomicLong;

/*
 * @description
 *   TweetNacl.c Java porting
 * */
public final class TweetNaclFast {

	private final static String TAG = "TweetNaclFast";

	/*
	 * @description Box algorithm, Public-key authenticated encryption
	 */
	public static final class Box {

		private final static String TAG = "Box";

		private AtomicLong nonce;

		private byte[] theirPublicKey;
		private byte[] mySecretKey;
		private byte[] sharedKey;

		public Box(byte[] theirPublicKey, byte[] mySecretKey) {
			this(theirPublicKey, mySecretKey, 68);
		}

		public Box(byte[] theirPublicKey, byte[] mySecretKey, long nonce) {
			this.theirPublicKey = theirPublicKey;
			this.mySecretKey = mySecretKey;

			this.nonce = new AtomicLong(nonce);

			// generate pre-computed shared key
			before();
		}

		public void setNonce(long nonce) {
			this.nonce.set(nonce);
		}
		public long getNonce() {
			return this.nonce.get();
		}
		public long incrNonce() {
			return this.nonce.incrementAndGet();
		}
		private byte[] generateNonce() {
			// generate nonce
			long nonce = this.nonce.get();

			byte[] n = new byte[nonceLength];
			for (int i = 0; i < nonceLength; i += 8) {
				n[i + 0] = (byte) (nonce >>> 0);
				n[i + 1] = (byte) (nonce >>> 8);
				n[i + 2] = (byte) (nonce >>> 16);
				n[i + 3] = (byte) (nonce >>> 24);
				n[i + 4] = (byte) (nonce >>> 32);
				n[i + 5] = (byte) (nonce >>> 40);
				n[i + 6] = (byte) (nonce >>> 48);
				n[i + 7] = (byte) (nonce >>> 56);
			}

			return n;
		}

		/*
		 * @description Encrypt and authenticates message using peer's public key, our
		 * secret key, and the given nonce, which must be unique for each distinct
		 * message for a key pair.
		 *
		 * Returns an encrypted and authenticated message, which is
		 * nacl.box.overheadLength longer than the original message.
		 */
		public byte[] box(byte[] message) {
			if (message == null)
				return null;
			return box(message, 0, message.length);
		}

		public byte[] box(byte[] message, final int moff) {
			if (!(message != null && message.length > moff))
				return null;
			return box(message, moff, message.length - moff);
		}

		public byte[] box(byte[] message, final int moff, final int mlen) {
			if (!(message != null && message.length >= (moff + mlen)))
				return null;

			// prepare shared key
			if (this.sharedKey == null)
				before();

			return after(message, moff, mlen);
		}

		/*
		 * @description Encrypt and authenticates message using peer's public key, our
		 * secret key, and the given nonce, which must be unique for each distinct
		 * message for a key pair.
		 *
		 * Explicitly pass the nonce
		 *
		 * Returns an encrypted and authenticated message, which is
		 * nacl.box.overheadLength longer than the original message.
		 */
		public byte[] box(byte[] message, byte[] theNonce) {
			if (message == null)
				return null;
			return box(message, 0, message.length, theNonce);
		}

		public byte[] box(byte[] message, final int moff, byte[] theNonce) {
			if (!(message != null && message.length > moff))
				return null;
			return box(message, moff, message.length - moff, theNonce);
		}

		public byte[] box(byte[] message, final int moff, final int mlen, byte[] theNonce) {
			if (!(message != null && message.length >= (moff + mlen) && theNonce != null
					&& theNonce.length == nonceLength))
				return null;

			// prepare shared key
			if (this.sharedKey == null)
				before();

			return after(message, moff, mlen, theNonce);
		}

		/*
		 * @description Authenticates and decrypts the given box with peer's public key,
		 * our secret key, and the given nonce.
		 *
		 * Returns the original message, or null if authentication fails.
		 */
		public byte[] open(byte[] box) {
			if (box == null)
				return null;

			// prepare shared key
			if (this.sharedKey == null)
				before();

			return open_after(box, 0, box.length);
		}
		public byte[] open(byte[] box, final int boxoff) {
			if (!(box != null && box.length > boxoff))
				return null;

			// prepare shared key
			if (this.sharedKey == null)
				before();

			return open_after(box, boxoff, box.length - boxoff);
		}
		public byte[] open(byte[] box, final int boxoff, final int boxlen) {
			if (!(box != null && box.length >= (boxoff + boxlen)))
				return null;

			// prepare shared key
			if (this.sharedKey == null)
				before();

			return open_after(box, boxoff, boxlen);
		}

		/*
		 * @description Authenticates and decrypts the given box with peer's public key,
		 * our secret key, and the given nonce. Explicit passing of nonce Returns the
		 * original message, or null if authentication fails.
		 */
		public byte[] open(byte[] box, byte[] theNonce) {
			if (!(box != null && theNonce != null && theNonce.length == nonceLength))
				return null;

			// prepare shared key
			if (this.sharedKey == null)
				before();

			return open_after(box, 0, box.length, theNonce);
		}
		public byte[] open(byte[] box, final int boxoff, byte[] theNonce) {
			if (!(box != null && box.length > boxoff && theNonce != null && theNonce.length == nonceLength))
				return null;

			// prepare shared key
			if (this.sharedKey == null)
				before();

			return open_after(box, boxoff, box.length - boxoff, theNonce);
		}
		public byte[] open(byte[] box, final int boxoff, final int boxlen, byte[] theNonce) {
			if (!(box != null && box.length >= (boxoff + boxlen) && theNonce != null && theNonce.length == nonceLength))
				return null;

			// prepare shared key
			if (this.sharedKey == null)
				before();

			return open_after(box, boxoff, boxlen, theNonce);
		}

		/*
		 * @description Returns a precomputed shared key which can be used in
		 * nacl.box.after and nacl.box.open.after.
		 */
		public byte[] before() {
			if (this.sharedKey == null) {
				this.sharedKey = new byte[sharedKeyLength];
				crypto_box_beforenm(this.sharedKey, this.theirPublicKey, this.mySecretKey);
			}

			return this.sharedKey;
		}

		/*
		 * @description Same as nacl.box, but uses a shared key precomputed with
		 * nacl.box.before.
		 */
		public byte[] after(byte[] message, final int moff, final int mlen) {
			return after(message, moff, mlen, generateNonce());
		}

		/*
		 * @description Same as nacl.box, but uses a shared key precomputed with
		 * nacl.box.before, and passes a nonce explicitly.
		 */
		public byte[] after(byte[] message, final int moff, final int mlen, byte[] theNonce) {
			// check message
			if (!(message != null && message.length >= (moff + mlen) && theNonce != null
					&& theNonce.length == nonceLength))
				return null;

			// message buffer
			byte[] m = new byte[mlen + zerobytesLength];

			// cipher buffer
			byte[] c = new byte[m.length];

			for (int i = 0; i < mlen; i++)
				m[i + zerobytesLength] = message[i + moff];

			if (0 != crypto_box_afternm(c, m, m.length, theNonce, sharedKey))
				return null;

			// wrap byte_buf_t on c offset@boxzerobytesLength
			/// return new byte_buf_t(c, boxzerobytesLength, c.length-boxzerobytesLength);
			byte[] ret = new byte[c.length - boxzerobytesLength];

			for (int i = 0; i < ret.length; i++)
				ret[i] = c[i + boxzerobytesLength];

			return ret;
		}

		/*
		 * @description Same as nacl.box.open, but uses a shared key pre-computed with
		 * nacl.box.before.
		 */
		public byte[] open_after(byte[] box, final int boxoff, final int boxlen) {
			return open_after(box, boxoff, boxlen, generateNonce());
		}

		public byte[] open_after(byte[] box, final int boxoff, final int boxlen, byte[] theNonce) {
			// check message
			if (!(box != null && box.length >= (boxoff + boxlen) && boxlen >= boxzerobytesLength))
				return null;

			// cipher buffer
			byte[] c = new byte[boxlen + boxzerobytesLength];

			// message buffer
			byte[] m = new byte[c.length];

			for (int i = 0; i < boxlen; i++)
				c[i + boxzerobytesLength] = box[i + boxoff];

			if (crypto_box_open_afternm(m, c, c.length, theNonce, sharedKey) != 0)
				return null;

			// wrap byte_buf_t on m offset@zerobytesLength
			/// return new byte_buf_t(m, zerobytesLength, m.length-zerobytesLength);
			byte[] ret = new byte[m.length - zerobytesLength];

			for (int i = 0; i < ret.length; i++)
				ret[i] = m[i + zerobytesLength];

			return ret;
		}

		/*
		 * @description Length of public key in bytes.
		 */
		public static final int publicKeyLength = 32;

		/*
		 * @description Length of secret key in bytes.
		 */
		public static final int secretKeyLength = 32;

		/*
		 * @description Length of precomputed shared key in bytes.
		 */
		public static final int sharedKeyLength = 32;

		/*
		 * @description Length of nonce in bytes.
		 */
		public static final int nonceLength = 24;

		/*
		 * @description zero bytes in case box
		 */
		public static final int zerobytesLength = 32;
		/*
		 * @description zero bytes in case open box
		 */
		public static final int boxzerobytesLength = 16;

		/*
		 * @description Length of overhead added to box compared to original message.
		 */
		public static final int overheadLength = 16;

		public static class KeyPair {
			private byte[] publicKey;
			private byte[] secretKey;

			public KeyPair() {
				publicKey = new byte[publicKeyLength];
				secretKey = new byte[secretKeyLength];
			}

			public byte[] getPublicKey() {
				return publicKey;
			}

			public byte[] getSecretKey() {
				return secretKey;
			}
		}

		/*
		 * @description Generates a new random key pair for box and returns it as an
		 * object with publicKey and secretKey members:
		 */
		public static KeyPair keyPair() {
			KeyPair kp = new KeyPair();

			crypto_box_keypair(kp.getPublicKey(), kp.getSecretKey());
			return kp;
		}

		public static KeyPair keyPair_fromSecretKey(byte[] secretKey) {
			KeyPair kp = new KeyPair();
			byte[] sk = kp.getSecretKey();
			byte[] pk = kp.getPublicKey();

			// copy sk
			for (int i = 0; i < sk.length; i++)
				sk[i] = secretKey[i];

			crypto_scalarmult_base(pk, sk);
			return kp;
		}

	}

	/*
	 * @description Secret Box algorithm, secret key
	 */
	public static final class SecretBox {

		private final static String TAG = "SecretBox";

		private AtomicLong nonce;

		private byte[] key;

		public SecretBox(byte[] key) {
			this(key, 68);
		}

		public SecretBox(byte[] key, long nonce) {
			this.key = key;

			this.nonce = new AtomicLong(nonce);
		}

		public void setNonce(long nonce) {
			this.nonce.set(nonce);
		}
		public long getNonce() {
			return this.nonce.get();
		}
		public long incrNonce() {
			return this.nonce.incrementAndGet();
		}
		private byte[] generateNonce() {
			// generate nonce
			long nonce = this.nonce.get();

			byte[] n = new byte[nonceLength];
			for (int i = 0; i < nonceLength; i += 8) {
				n[i + 0] = (byte) (nonce >>> 0);
				n[i + 1] = (byte) (nonce >>> 8);
				n[i + 2] = (byte) (nonce >>> 16);
				n[i + 3] = (byte) (nonce >>> 24);
				n[i + 4] = (byte) (nonce >>> 32);
				n[i + 5] = (byte) (nonce >>> 40);
				n[i + 6] = (byte) (nonce >>> 48);
				n[i + 7] = (byte) (nonce >>> 56);
			}

			return n;
		}

		/*
		 * @description Encrypt and authenticates message using the key and the nonce.
		 * The nonce must be unique for each distinct message for this key.
		 *
		 * Returns an encrypted and authenticated message, which is
		 * nacl.secretbox.overheadLength longer than the original message.
		 */
		public byte[] box(byte[] message) {
			if (message == null)
				return null;
			return box(message, 0, message.length);
		}

		public byte[] box(byte[] message, final int moff) {
			if (!(message != null && message.length > moff))
				return null;
			return box(message, moff, message.length - moff);
		}

		public byte[] box(byte[] message, final int moff, final int mlen) {
			// check message
			if (!(message != null && message.length >= (moff + mlen)))
				return null;
			return box(message, moff, message.length - moff, generateNonce());
		}

		public byte[] box(byte[] message, byte[] theNonce) {
			if (message == null)
				return null;
			return box(message, 0, message.length, theNonce);
		}

		public byte[] box(byte[] message, final int moff, byte[] theNonce) {
			if (!(message != null && message.length > moff))
				return null;
			return box(message, moff, message.length - moff, theNonce);
		}

		public byte[] box(byte[] message, final int moff, final int mlen, byte[] theNonce) {
			// check message
			if (!(message != null && message.length >= (moff + mlen) && theNonce != null
					&& theNonce.length == nonceLength))
				return null;

			// message buffer
			byte[] m = new byte[mlen + zerobytesLength];

			// cipher buffer
			byte[] c = new byte[m.length];

			for (int i = 0; i < mlen; i++)
				m[i + zerobytesLength] = message[i + moff];

			if (0 != crypto_secretbox(c, m, m.length, theNonce, key))
				return null;

			// TBD optimizing ...
			// wrap byte_buf_t on c offset@boxzerobytesLength
			/// return new byte_buf_t(c, boxzerobytesLength, c.length-boxzerobytesLength);
			byte[] ret = new byte[c.length - boxzerobytesLength];

			for (int i = 0; i < ret.length; i++)
				ret[i] = c[i + boxzerobytesLength];

			return ret;
		}

		/*
		 * @description Authenticates and decrypts the given secret box using the key
		 * and the nonce.
		 *
		 * Returns the original message, or null if authentication fails.
		 */
		public byte[] open(byte[] box) {
			if (box == null)
				return null;
			return open(box, 0, box.length);
		}

		public byte[] open(byte[] box, final int boxoff) {
			if (!(box != null && box.length > boxoff))
				return null;
			return open(box, boxoff, box.length - boxoff);
		}

		public byte[] open(byte[] box, final int boxoff, final int boxlen) {
			// check message
			if (!(box != null && box.length >= (boxoff + boxlen) && boxlen >= boxzerobytesLength))
				return null;
			return open(box, boxoff, box.length - boxoff, generateNonce());
		}

		public byte[] open(byte[] box, byte[] theNonce) {
			if (box == null)
				return null;
			return open(box, 0, box.length, theNonce);
		}

		public byte[] open(byte[] box, final int boxoff, byte[] theNonce) {
			if (!(box != null && box.length > boxoff))
				return null;
			return open(box, boxoff, box.length - boxoff, theNonce);
		}

		public byte[] open(byte[] box, final int boxoff, final int boxlen, byte[] theNonce) {
			// check message
			if (!(box != null && box.length >= (boxoff + boxlen) && boxlen >= boxzerobytesLength && theNonce != null
					&& theNonce.length == nonceLength))
				return null;

			// cipher buffer
			byte[] c = new byte[boxlen + boxzerobytesLength];

			// message buffer
			byte[] m = new byte[c.length];

			for (int i = 0; i < boxlen; i++)
				c[i + boxzerobytesLength] = box[i + boxoff];

			if (0 != crypto_secretbox_open(m, c, c.length, theNonce, key))
				return null;

			// wrap byte_buf_t on m offset@zerobytesLength
			/// return new byte_buf_t(m, zerobytesLength, m.length-zerobytesLength);
			byte[] ret = new byte[m.length - zerobytesLength];

			for (int i = 0; i < ret.length; i++)
				ret[i] = m[i + zerobytesLength];

			return ret;
		}

		/*
		 * @description Length of key in bytes.
		 */
		public static final int keyLength = 32;

		/*
		 * @description Length of nonce in bytes.
		 */
		public static final int nonceLength = 24;

		/*
		 * @description Length of overhead added to secret box compared to original
		 * message.
		 */
		public static final int overheadLength = 16;

		/*
		 * @description zero bytes in case box
		 */
		public static final int zerobytesLength = 32;
		/*
		 * @description zero bytes in case open box
		 */
		public static final int boxzerobytesLength = 16;

	}

	/*
	 * @description Scalar multiplication, Implements curve25519.
	 */
	public static final class ScalarMult {

		private final static String TAG = "ScalarMult";

		/*
		 * @description Multiplies an integer n by a group element p and returns the
		 * resulting group element.
		 */
		public static byte[] scalseMult(byte[] n, byte[] p) {
			if (!(n.length == scalarLength && p.length == groupElementLength))
				return null;

			byte[] q = new byte[scalarLength];

			crypto_scalarmult(q, n, p);

			return q;
		}

		/*
		 * @description Multiplies an integer n by a standard group element and returns
		 * the resulting group element.
		 */
		public static byte[] scalseMult_base(byte[] n) {
			if (!(n.length == scalarLength))
				return null;

			byte[] q = new byte[scalarLength];

			crypto_scalarmult_base(q, n);

			return q;
		}

		/*
		 * @description Length of scalar in bytes.
		 */
		public static final int scalarLength = 32;

		/*
		 * @description Length of group element in bytes.
		 */
		public static final int groupElementLength = 32;

	}

	/*
	 * @description Hash algorithm, Implements SHA-512.
	 */
	public static final class Hash {

		private final static String TAG = "Hash";

		/*
		 * @description Returns SHA-512 hash of the message.
		 */
		public static byte[] sha512(byte[] message) {
			if (!(message != null && message.length > 0))
				return null;

			byte[] out = new byte[hashLength];

			crypto_hash(out, message);

			return out;
		}
		public static byte[] sha512(String message) throws UnsupportedEncodingException {
			return sha512(message.getBytes("utf-8"));
		}

		/*
		 * @description Length of hash in bytes.
		 */
		public static final int hashLength = 64;

	}

	/*
	 * @description Signature algorithm, Implements ed25519.
	 */
	public static final class Signature {

		private final static String TAG = "Signature";

		private byte[] theirPublicKey;
		private byte[] mySecretKey;

		public Signature(byte[] theirPublicKey, byte[] mySecretKey) {
			this.theirPublicKey = theirPublicKey;
			this.mySecretKey = mySecretKey;
		}

		/*
		 * @description Signs the message using the secret key and returns a signed
		 * message.
		 */
		public byte[] sign(byte[] message) {
			if (message == null)
				return null;

			return sign(message, 0, message.length);
		}
		public byte[] sign(byte[] message, final int moff) {
			if (!(message != null && message.length > moff))
				return null;

			return sign(message, moff, message.length - moff);
		}
		public byte[] sign(byte[] message, final int moff, final int mlen) {
			// check message
			if (!(message != null && message.length >= (moff + mlen)))
				return null;

			// signed message
			byte[] sm = new byte[mlen + signatureLength];

			crypto_sign(sm, -1, message, moff, mlen, mySecretKey);

			return sm;
		}

		/*
		 * @description Verifies the signed message and returns the message without
		 * signature. Returns null if verification failed.
		 */
		public byte[] open(byte[] signedMessage) {
			if (signedMessage == null)
				return null;

			return open(signedMessage, 0, signedMessage.length);
		}
		public byte[] open(byte[] signedMessage, final int smoff) {
			if (!(signedMessage != null && signedMessage.length > smoff))
				return null;

			return open(signedMessage, smoff, signedMessage.length - smoff);
		}
		public byte[] open(byte[] signedMessage, final int smoff, final int smlen) {
			// check sm length
			if (!(signedMessage != null && signedMessage.length >= (smoff + smlen) && smlen >= signatureLength))
				return null;

			// temp buffer
			byte[] tmp = new byte[smlen];

			if (0 != crypto_sign_open(tmp, -1, signedMessage, smoff, smlen, theirPublicKey))
				return null;

			// message
			byte[] msg = new byte[smlen - signatureLength];
			for (int i = 0; i < msg.length; i++)
				msg[i] = signedMessage[smoff + i + signatureLength];

			return msg;
		}

		/*
		 * @description Signs the message using the secret key and returns a signature.
		 */
		public byte[] detached(byte[] message) {
			byte[] signedMsg = this.sign(message);
			byte[] sig = new byte[signatureLength];
			for (int i = 0; i < sig.length; i++)
				sig[i] = signedMsg[i];
			return sig;
		}

		/*
		 * @description Verifies the signature for the message and returns true if
		 * verification succeeded or false if it failed.
		 */
		public boolean detached_verify(byte[] message, byte[] signature) {
			if (signature.length != signatureLength)
				return false;
			if (theirPublicKey.length != publicKeyLength)
				return false;
			byte[] sm = new byte[signatureLength + message.length];
			byte[] m = new byte[signatureLength + message.length];
			for (int i = 0; i < signatureLength; i++)
				sm[i] = signature[i];
			for (int i = 0; i < message.length; i++)
				sm[i + signatureLength] = message[i];
			return (crypto_sign_open(m, -1, sm, 0, sm.length, theirPublicKey) >= 0);
		}

		/*
		 * @description Generates new random key pair for signing and returns it as an
		 * object with publicKey and secretKey members
		 */
		public static class KeyPair {
			private byte[] publicKey;
			private byte[] secretKey;

			public KeyPair() {
				publicKey = new byte[publicKeyLength];
				secretKey = new byte[secretKeyLength];
			}

			public byte[] getPublicKey() {
				return publicKey;
			}

			public byte[] getSecretKey() {
				return secretKey;
			}
		}

		/*
		 * @description Signs the message using the secret key and returns a signed
		 * message.
		 */
		public static KeyPair keyPair() {
			KeyPair kp = new KeyPair();

			crypto_sign_keypair(kp.getPublicKey(), kp.getSecretKey(), false);
			return kp;
		}
		public static KeyPair keyPair_fromSecretKey(byte[] secretKey) {
			KeyPair kp = new KeyPair();
			byte[] pk = kp.getPublicKey();
			byte[] sk = kp.getSecretKey();

			// copy sk
			for (int i = 0; i < kp.getSecretKey().length; i++)
				sk[i] = secretKey[i];

			// copy pk from sk
			for (int i = 0; i < kp.getPublicKey().length; i++)
				pk[i] = secretKey[32 + i]; // hard-copy

			return kp;
		}

		public static KeyPair keyPair_fromSeed(byte[] seed) {
			KeyPair kp = new KeyPair();
			byte[] pk = kp.getPublicKey();
			byte[] sk = kp.getSecretKey();

			// copy sk
			for (int i = 0; i < seedLength; i++)
				sk[i] = seed[i];

			// generate pk from sk
			crypto_sign_keypair(pk, sk, true);

			return kp;
		}

		/*
		 * @description Length of signing public key in bytes.
		 */
		public static final int publicKeyLength = 32;

		/*
		 * @description Length of signing secret key in bytes.
		 */
		public static final int secretKeyLength = 64;

		/*
		 * @description Length of seed for nacl.sign.keyPair.fromSeed in bytes.
		 */
		public static final int seedLength = 32;

		/*
		 * @description Length of signature in bytes.
		 */
		public static final int signatureLength = 64;
	}

	////////////////////////////////////////////////////////////////////////////////////
	/*
	 * @description Codes below are ported tweetnacl-fast.js from
	 * TweetNacl.c/TweetNacl.h
	 */

	private static final byte[] _0 = new byte[16];
	private static final byte[] _9 = new byte[32];
	static {
		/// for (int i = 0; i < _0.length; i ++) _0[i] = 0;

		/// for (int i = 0; i < _9.length; i ++) _9[i] = 0;
		_9[0] = 9;
	}

	private static final long[] gf0 = new long[16];
	private static final long[] gf1 = new long[16];
	private static final long[] _121665 = new long[16];
	static {
		/// for (int i = 0; i < gf0.length; i ++) gf0[i] = 0;

		/// for (int i = 0; i < gf1.length; i ++) gf1[i] = 0;
		gf1[0] = 1;

		/// for (int i = 0; i < _121665.length; i ++) _121665[i] = 0;
		_121665[0] = 0xDB41;
		_121665[1] = 1;
	}

	private static final long[] D = new long[]{0x78a3, 0x1359, 0x4dca, 0x75eb, 0xd8ab, 0x4141, 0x0a4d, 0x0070, 0xe898,
			0x7779, 0x4079, 0x8cc7, 0xfe73, 0x2b6f, 0x6cee, 0x5203};
	private static final long[] D2 = new long[]{0xf159, 0x26b2, 0x9b94, 0xebd6, 0xb156, 0x8283, 0x149a, 0x00e0, 0xd130,
			0xeef3, 0x80f2, 0x198e, 0xfce7, 0x56df, 0xd9dc, 0x2406};
	private static final long[] X = new long[]{0xd51a, 0x8f25, 0x2d60, 0xc956, 0xa7b2, 0x9525, 0xc760, 0x692c, 0xdc5c,
			0xfdd6, 0xe231, 0xc0a4, 0x53fe, 0xcd6e, 0x36d3, 0x2169};
	private static final long[] Y = new long[]{0x6658, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666,
			0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666};
	private static final long[] I = new long[]{0xa0b0, 0x4a0e, 0x1b27, 0xc4ee, 0xe478, 0xad2f, 0x1806, 0x2f43, 0xd7a7,
			0x3dfb, 0x0099, 0x2b4d, 0xdf0b, 0x4fc1, 0x2480, 0x2b83};

	private static void ts64(byte[] x, final int xoff, long u) {
		/// int i;
		/// for (i = 7;i >= 0;--i) { x[i+xoff] = (byte)(u&0xff); u >>>= 8; }

		x[7 + xoff] = (byte) (u & 0xff);
		u >>>= 8;
		x[6 + xoff] = (byte) (u & 0xff);
		u >>>= 8;
		x[5 + xoff] = (byte) (u & 0xff);
		u >>>= 8;
		x[4 + xoff] = (byte) (u & 0xff);
		u >>>= 8;
		x[3 + xoff] = (byte) (u & 0xff);
		u >>>= 8;
		x[2 + xoff] = (byte) (u & 0xff);
		u >>>= 8;
		x[1 + xoff] = (byte) (u & 0xff);
		u >>>= 8;
		x[0 + xoff] = (byte) (u & 0xff); /// u >>>= 8;
	}

	private static int vn(byte[] x, final int xoff, byte[] y, final int yoff, int n) {
		int i, d = 0;
		for (i = 0; i < n; i++)
			d |= (x[i + xoff] ^ y[i + yoff]) & 0xff;
		return (1 & ((d - 1) >>> 8)) - 1;
	}

	private static int crypto_verify_16(byte[] x, final int xoff, byte[] y, final int yoff) {
		return vn(x, xoff, y, yoff, 16);
	}
	public static int crypto_verify_16(byte[] x, byte[] y) {
		return crypto_verify_16(x, 0, y, 0);
	}

	private static int crypto_verify_32(byte[] x, final int xoff, byte[] y, final int yoff) {
		return vn(x, xoff, y, yoff, 32);
	}
	public static int crypto_verify_32(byte[] x, byte[] y) {
		return crypto_verify_32(x, 0, y, 0);
	}

	private static void core_salsa20(byte[] o, byte[] p, byte[] k, byte[] c) {
		int j0 = c[0] & 0xff | (c[1] & 0xff) << 8 | (c[2] & 0xff) << 16 | (c[3] & 0xff) << 24,
				j1 = k[0] & 0xff | (k[1] & 0xff) << 8 | (k[2] & 0xff) << 16 | (k[3] & 0xff) << 24,
				j2 = k[4] & 0xff | (k[5] & 0xff) << 8 | (k[6] & 0xff) << 16 | (k[7] & 0xff) << 24,
				j3 = k[8] & 0xff | (k[9] & 0xff) << 8 | (k[10] & 0xff) << 16 | (k[11] & 0xff) << 24,
				j4 = k[12] & 0xff | (k[13] & 0xff) << 8 | (k[14] & 0xff) << 16 | (k[15] & 0xff) << 24,
				j5 = c[4] & 0xff | (c[5] & 0xff) << 8 | (c[6] & 0xff) << 16 | (c[7] & 0xff) << 24,
				j6 = p[0] & 0xff | (p[1] & 0xff) << 8 | (p[2] & 0xff) << 16 | (p[3] & 0xff) << 24,
				j7 = p[4] & 0xff | (p[5] & 0xff) << 8 | (p[6] & 0xff) << 16 | (p[7] & 0xff) << 24,
				j8 = p[8] & 0xff | (p[9] & 0xff) << 8 | (p[10] & 0xff) << 16 | (p[11] & 0xff) << 24,
				j9 = p[12] & 0xff | (p[13] & 0xff) << 8 | (p[14] & 0xff) << 16 | (p[15] & 0xff) << 24,
				j10 = c[8] & 0xff | (c[9] & 0xff) << 8 | (c[10] & 0xff) << 16 | (c[11] & 0xff) << 24,
				j11 = k[16] & 0xff | (k[17] & 0xff) << 8 | (k[18] & 0xff) << 16 | (k[19] & 0xff) << 24,
				j12 = k[20] & 0xff | (k[21] & 0xff) << 8 | (k[22] & 0xff) << 16 | (k[23] & 0xff) << 24,
				j13 = k[24] & 0xff | (k[25] & 0xff) << 8 | (k[26] & 0xff) << 16 | (k[27] & 0xff) << 24,
				j14 = k[28] & 0xff | (k[29] & 0xff) << 8 | (k[30] & 0xff) << 16 | (k[31] & 0xff) << 24,
				j15 = c[12] & 0xff | (c[13] & 0xff) << 8 | (c[14] & 0xff) << 16 | (c[15] & 0xff) << 24;

		int x0 = j0, x1 = j1, x2 = j2, x3 = j3, x4 = j4, x5 = j5, x6 = j6, x7 = j7, x8 = j8, x9 = j9, x10 = j10,
				x11 = j11, x12 = j12, x13 = j13, x14 = j14, x15 = j15, u;

		for (int i = 0; i < 20; i += 2) {
			u = x0 + x12 | 0;
			x4 ^= u << 7 | u >>> (32 - 7);
			u = x4 + x0 | 0;
			x8 ^= u << 9 | u >>> (32 - 9);
			u = x8 + x4 | 0;
			x12 ^= u << 13 | u >>> (32 - 13);
			u = x12 + x8 | 0;
			x0 ^= u << 18 | u >>> (32 - 18);

			u = x5 + x1 | 0;
			x9 ^= u << 7 | u >>> (32 - 7);
			u = x9 + x5 | 0;
			x13 ^= u << 9 | u >>> (32 - 9);
			u = x13 + x9 | 0;
			x1 ^= u << 13 | u >>> (32 - 13);
			u = x1 + x13 | 0;
			x5 ^= u << 18 | u >>> (32 - 18);

			u = x10 + x6 | 0;
			x14 ^= u << 7 | u >>> (32 - 7);
			u = x14 + x10 | 0;
			x2 ^= u << 9 | u >>> (32 - 9);
			u = x2 + x14 | 0;
			x6 ^= u << 13 | u >>> (32 - 13);
			u = x6 + x2 | 0;
			x10 ^= u << 18 | u >>> (32 - 18);

			u = x15 + x11 | 0;
			x3 ^= u << 7 | u >>> (32 - 7);
			u = x3 + x15 | 0;
			x7 ^= u << 9 | u >>> (32 - 9);
			u = x7 + x3 | 0;
			x11 ^= u << 13 | u >>> (32 - 13);
			u = x11 + x7 | 0;
			x15 ^= u << 18 | u >>> (32 - 18);

			u = x0 + x3 | 0;
			x1 ^= u << 7 | u >>> (32 - 7);
			u = x1 + x0 | 0;
			x2 ^= u << 9 | u >>> (32 - 9);
			u = x2 + x1 | 0;
			x3 ^= u << 13 | u >>> (32 - 13);
			u = x3 + x2 | 0;
			x0 ^= u << 18 | u >>> (32 - 18);

			u = x5 + x4 | 0;
			x6 ^= u << 7 | u >>> (32 - 7);
			u = x6 + x5 | 0;
			x7 ^= u << 9 | u >>> (32 - 9);
			u = x7 + x6 | 0;
			x4 ^= u << 13 | u >>> (32 - 13);
			u = x4 + x7 | 0;
			x5 ^= u << 18 | u >>> (32 - 18);

			u = x10 + x9 | 0;
			x11 ^= u << 7 | u >>> (32 - 7);
			u = x11 + x10 | 0;
			x8 ^= u << 9 | u >>> (32 - 9);
			u = x8 + x11 | 0;
			x9 ^= u << 13 | u >>> (32 - 13);
			u = x9 + x8 | 0;
			x10 ^= u << 18 | u >>> (32 - 18);

			u = x15 + x14 | 0;
			x12 ^= u << 7 | u >>> (32 - 7);
			u = x12 + x15 | 0;
			x13 ^= u << 9 | u >>> (32 - 9);
			u = x13 + x12 | 0;
			x14 ^= u << 13 | u >>> (32 - 13);
			u = x14 + x13 | 0;
			x15 ^= u << 18 | u >>> (32 - 18);
		}
		x0 = x0 + j0 | 0;
		x1 = x1 + j1 | 0;
		x2 = x2 + j2 | 0;
		x3 = x3 + j3 | 0;
		x4 = x4 + j4 | 0;
		x5 = x5 + j5 | 0;
		x6 = x6 + j6 | 0;
		x7 = x7 + j7 | 0;
		x8 = x8 + j8 | 0;
		x9 = x9 + j9 | 0;
		x10 = x10 + j10 | 0;
		x11 = x11 + j11 | 0;
		x12 = x12 + j12 | 0;
		x13 = x13 + j13 | 0;
		x14 = x14 + j14 | 0;
		x15 = x15 + j15 | 0;

		o[0] = (byte) (x0 >>> 0 & 0xff);
		o[1] = (byte) (x0 >>> 8 & 0xff);
		o[2] = (byte) (x0 >>> 16 & 0xff);
		o[3] = (byte) (x0 >>> 24 & 0xff);

		o[4] = (byte) (x1 >>> 0 & 0xff);
		o[5] = (byte) (x1 >>> 8 & 0xff);
		o[6] = (byte) (x1 >>> 16 & 0xff);
		o[7] = (byte) (x1 >>> 24 & 0xff);

		o[8] = (byte) (x2 >>> 0 & 0xff);
		o[9] = (byte) (x2 >>> 8 & 0xff);
		o[10] = (byte) (x2 >>> 16 & 0xff);
		o[11] = (byte) (x2 >>> 24 & 0xff);

		o[12] = (byte) (x3 >>> 0 & 0xff);
		o[13] = (byte) (x3 >>> 8 & 0xff);
		o[14] = (byte) (x3 >>> 16 & 0xff);
		o[15] = (byte) (x3 >>> 24 & 0xff);

		o[16] = (byte) (x4 >>> 0 & 0xff);
		o[17] = (byte) (x4 >>> 8 & 0xff);
		o[18] = (byte) (x4 >>> 16 & 0xff);
		o[19] = (byte) (x4 >>> 24 & 0xff);

		o[20] = (byte) (x5 >>> 0 & 0xff);
		o[21] = (byte) (x5 >>> 8 & 0xff);
		o[22] = (byte) (x5 >>> 16 & 0xff);
		o[23] = (byte) (x5 >>> 24 & 0xff);

		o[24] = (byte) (x6 >>> 0 & 0xff);
		o[25] = (byte) (x6 >>> 8 & 0xff);
		o[26] = (byte) (x6 >>> 16 & 0xff);
		o[27] = (byte) (x6 >>> 24 & 0xff);

		o[28] = (byte) (x7 >>> 0 & 0xff);
		o[29] = (byte) (x7 >>> 8 & 0xff);
		o[30] = (byte) (x7 >>> 16 & 0xff);
		o[31] = (byte) (x7 >>> 24 & 0xff);

		o[32] = (byte) (x8 >>> 0 & 0xff);
		o[33] = (byte) (x8 >>> 8 & 0xff);
		o[34] = (byte) (x8 >>> 16 & 0xff);
		o[35] = (byte) (x8 >>> 24 & 0xff);

		o[36] = (byte) (x9 >>> 0 & 0xff);
		o[37] = (byte) (x9 >>> 8 & 0xff);
		o[38] = (byte) (x9 >>> 16 & 0xff);
		o[39] = (byte) (x9 >>> 24 & 0xff);

		o[40] = (byte) (x10 >>> 0 & 0xff);
		o[41] = (byte) (x10 >>> 8 & 0xff);
		o[42] = (byte) (x10 >>> 16 & 0xff);
		o[43] = (byte) (x10 >>> 24 & 0xff);

		o[44] = (byte) (x11 >>> 0 & 0xff);
		o[45] = (byte) (x11 >>> 8 & 0xff);
		o[46] = (byte) (x11 >>> 16 & 0xff);
		o[47] = (byte) (x11 >>> 24 & 0xff);

		o[48] = (byte) (x12 >>> 0 & 0xff);
		o[49] = (byte) (x12 >>> 8 & 0xff);
		o[50] = (byte) (x12 >>> 16 & 0xff);
		o[51] = (byte) (x12 >>> 24 & 0xff);

		o[52] = (byte) (x13 >>> 0 & 0xff);
		o[53] = (byte) (x13 >>> 8 & 0xff);
		o[54] = (byte) (x13 >>> 16 & 0xff);
		o[55] = (byte) (x13 >>> 24 & 0xff);

		o[56] = (byte) (x14 >>> 0 & 0xff);
		o[57] = (byte) (x14 >>> 8 & 0xff);
		o[58] = (byte) (x14 >>> 16 & 0xff);
		o[59] = (byte) (x14 >>> 24 & 0xff);

		o[60] = (byte) (x15 >>> 0 & 0xff);
		o[61] = (byte) (x15 >>> 8 & 0xff);
		o[62] = (byte) (x15 >>> 16 & 0xff);
		o[63] = (byte) (x15 >>> 24 & 0xff);

		/*
		 * String dbgt = ""; for (int dbg = 0; dbg < o.length; dbg ++) dbgt +=
		 * " "+o[dbg]; Log.d(TAG, "core_salsa20 -> "+dbgt);
		 */
	}

	private static void core_hsalsa20(byte[] o, byte[] p, byte[] k, byte[] c) {
		int j0 = c[0] & 0xff | (c[1] & 0xff) << 8 | (c[2] & 0xff) << 16 | (c[3] & 0xff) << 24,
				j1 = k[0] & 0xff | (k[1] & 0xff) << 8 | (k[2] & 0xff) << 16 | (k[3] & 0xff) << 24,
				j2 = k[4] & 0xff | (k[5] & 0xff) << 8 | (k[6] & 0xff) << 16 | (k[7] & 0xff) << 24,
				j3 = k[8] & 0xff | (k[9] & 0xff) << 8 | (k[10] & 0xff) << 16 | (k[11] & 0xff) << 24,
				j4 = k[12] & 0xff | (k[13] & 0xff) << 8 | (k[14] & 0xff) << 16 | (k[15] & 0xff) << 24,
				j5 = c[4] & 0xff | (c[5] & 0xff) << 8 | (c[6] & 0xff) << 16 | (c[7] & 0xff) << 24,
				j6 = p[0] & 0xff | (p[1] & 0xff) << 8 | (p[2] & 0xff) << 16 | (p[3] & 0xff) << 24,
				j7 = p[4] & 0xff | (p[5] & 0xff) << 8 | (p[6] & 0xff) << 16 | (p[7] & 0xff) << 24,
				j8 = p[8] & 0xff | (p[9] & 0xff) << 8 | (p[10] & 0xff) << 16 | (p[11] & 0xff) << 24,
				j9 = p[12] & 0xff | (p[13] & 0xff) << 8 | (p[14] & 0xff) << 16 | (p[15] & 0xff) << 24,
				j10 = c[8] & 0xff | (c[9] & 0xff) << 8 | (c[10] & 0xff) << 16 | (c[11] & 0xff) << 24,
				j11 = k[16] & 0xff | (k[17] & 0xff) << 8 | (k[18] & 0xff) << 16 | (k[19] & 0xff) << 24,
				j12 = k[20] & 0xff | (k[21] & 0xff) << 8 | (k[22] & 0xff) << 16 | (k[23] & 0xff) << 24,
				j13 = k[24] & 0xff | (k[25] & 0xff) << 8 | (k[26] & 0xff) << 16 | (k[27] & 0xff) << 24,
				j14 = k[28] & 0xff | (k[29] & 0xff) << 8 | (k[30] & 0xff) << 16 | (k[31] & 0xff) << 24,
				j15 = c[12] & 0xff | (c[13] & 0xff) << 8 | (c[14] & 0xff) << 16 | (c[15] & 0xff) << 24;

		int x0 = j0, x1 = j1, x2 = j2, x3 = j3, x4 = j4, x5 = j5, x6 = j6, x7 = j7, x8 = j8, x9 = j9, x10 = j10,
				x11 = j11, x12 = j12, x13 = j13, x14 = j14, x15 = j15, u;

		for (int i = 0; i < 20; i += 2) {
			u = x0 + x12 | 0;
			x4 ^= u << 7 | u >>> (32 - 7);
			u = x4 + x0 | 0;
			x8 ^= u << 9 | u >>> (32 - 9);
			u = x8 + x4 | 0;
			x12 ^= u << 13 | u >>> (32 - 13);
			u = x12 + x8 | 0;
			x0 ^= u << 18 | u >>> (32 - 18);

			u = x5 + x1 | 0;
			x9 ^= u << 7 | u >>> (32 - 7);
			u = x9 + x5 | 0;
			x13 ^= u << 9 | u >>> (32 - 9);
			u = x13 + x9 | 0;
			x1 ^= u << 13 | u >>> (32 - 13);
			u = x1 + x13 | 0;
			x5 ^= u << 18 | u >>> (32 - 18);

			u = x10 + x6 | 0;
			x14 ^= u << 7 | u >>> (32 - 7);
			u = x14 + x10 | 0;
			x2 ^= u << 9 | u >>> (32 - 9);
			u = x2 + x14 | 0;
			x6 ^= u << 13 | u >>> (32 - 13);
			u = x6 + x2 | 0;
			x10 ^= u << 18 | u >>> (32 - 18);

			u = x15 + x11 | 0;
			x3 ^= u << 7 | u >>> (32 - 7);
			u = x3 + x15 | 0;
			x7 ^= u << 9 | u >>> (32 - 9);
			u = x7 + x3 | 0;
			x11 ^= u << 13 | u >>> (32 - 13);
			u = x11 + x7 | 0;
			x15 ^= u << 18 | u >>> (32 - 18);

			u = x0 + x3 | 0;
			x1 ^= u << 7 | u >>> (32 - 7);
			u = x1 + x0 | 0;
			x2 ^= u << 9 | u >>> (32 - 9);
			u = x2 + x1 | 0;
			x3 ^= u << 13 | u >>> (32 - 13);
			u = x3 + x2 | 0;
			x0 ^= u << 18 | u >>> (32 - 18);

			u = x5 + x4 | 0;
			x6 ^= u << 7 | u >>> (32 - 7);
			u = x6 + x5 | 0;
			x7 ^= u << 9 | u >>> (32 - 9);
			u = x7 + x6 | 0;
			x4 ^= u << 13 | u >>> (32 - 13);
			u = x4 + x7 | 0;
			x5 ^= u << 18 | u >>> (32 - 18);

			u = x10 + x9 | 0;
			x11 ^= u << 7 | u >>> (32 - 7);
			u = x11 + x10 | 0;
			x8 ^= u << 9 | u >>> (32 - 9);
			u = x8 + x11 | 0;
			x9 ^= u << 13 | u >>> (32 - 13);
			u = x9 + x8 | 0;
			x10 ^= u << 18 | u >>> (32 - 18);

			u = x15 + x14 | 0;
			x12 ^= u << 7 | u >>> (32 - 7);
			u = x12 + x15 | 0;
			x13 ^= u << 9 | u >>> (32 - 9);
			u = x13 + x12 | 0;
			x14 ^= u << 13 | u >>> (32 - 13);
			u = x14 + x13 | 0;
			x15 ^= u << 18 | u >>> (32 - 18);
		}

		o[0] = (byte) (x0 >>> 0 & 0xff);
		o[1] = (byte) (x0 >>> 8 & 0xff);
		o[2] = (byte) (x0 >>> 16 & 0xff);
		o[3] = (byte) (x0 >>> 24 & 0xff);

		o[4] = (byte) (x5 >>> 0 & 0xff);
		o[5] = (byte) (x5 >>> 8 & 0xff);
		o[6] = (byte) (x5 >>> 16 & 0xff);
		o[7] = (byte) (x5 >>> 24 & 0xff);

		o[8] = (byte) (x10 >>> 0 & 0xff);
		o[9] = (byte) (x10 >>> 8 & 0xff);
		o[10] = (byte) (x10 >>> 16 & 0xff);
		o[11] = (byte) (x10 >>> 24 & 0xff);

		o[12] = (byte) (x15 >>> 0 & 0xff);
		o[13] = (byte) (x15 >>> 8 & 0xff);
		o[14] = (byte) (x15 >>> 16 & 0xff);
		o[15] = (byte) (x15 >>> 24 & 0xff);

		o[16] = (byte) (x6 >>> 0 & 0xff);
		o[17] = (byte) (x6 >>> 8 & 0xff);
		o[18] = (byte) (x6 >>> 16 & 0xff);
		o[19] = (byte) (x6 >>> 24 & 0xff);

		o[20] = (byte) (x7 >>> 0 & 0xff);
		o[21] = (byte) (x7 >>> 8 & 0xff);
		o[22] = (byte) (x7 >>> 16 & 0xff);
		o[23] = (byte) (x7 >>> 24 & 0xff);

		o[24] = (byte) (x8 >>> 0 & 0xff);
		o[25] = (byte) (x8 >>> 8 & 0xff);
		o[26] = (byte) (x8 >>> 16 & 0xff);
		o[27] = (byte) (x8 >>> 24 & 0xff);

		o[28] = (byte) (x9 >>> 0 & 0xff);
		o[29] = (byte) (x9 >>> 8 & 0xff);
		o[30] = (byte) (x9 >>> 16 & 0xff);
		o[31] = (byte) (x9 >>> 24 & 0xff);

		/*
		 * String dbgt = ""; for (int dbg = 0; dbg < o.length; dbg ++) dbgt +=
		 * " "+o[dbg]; Log.d(TAG, "core_hsalsa20 -> "+dbgt);
		 */
	}

	public static int crypto_core_salsa20(byte[] out, byte[] in, byte[] k, byte[] c) {
		/// core(out,in,k,c,0);
		core_salsa20(out, in, k, c);

		/// String dbgt = "";
		/// for (int dbg = 0; dbg < out.length; dbg ++) dbgt += " "+out[dbg];
		/// L/og.d(TAG, "crypto_core_salsa20 -> "+dbgt);

		return 0;
	}

	public static int crypto_core_hsalsa20(byte[] out, byte[] in, byte[] k, byte[] c) {
		/// core(out,in,k,c,1);
		core_hsalsa20(out, in, k, c);

		/// String dbgt = "";
		/// for (int dbg = 0; dbg < out.length; dbg ++) dbgt += " "+out[dbg];
		/// L/og.d(TAG, "crypto_core_hsalsa20 -> "+dbgt);

		return 0;
	}

	// "expand 32-byte k"
	private static final byte[] sigma = {101, 120, 112, 97, 110, 100, 32, 51, 50, 45, 98, 121, 116, 101, 32, 107};

	/*
	 * static { try { sigma = "expand 32-byte k".getBytes("utf-8"); } catch
	 * (UnsupportedEncodingException e) { e.printStackTrace(); } }
	 */

	private static int crypto_stream_salsa20_xor(byte[] c, int cpos, byte[] m, int mpos, long b, byte[] n, byte[] k) {
		byte[] z = new byte[16], x = new byte[64];
		int u, i;
		for (i = 0; i < 16; i++)
			z[i] = 0;
		for (i = 0; i < 8; i++)
			z[i] = n[i];
		while (b >= 64) {
			crypto_core_salsa20(x, z, k, sigma);
			for (i = 0; i < 64; i++)
				c[cpos + i] = (byte) ((m[mpos + i] ^ x[i]) & 0xff);
			u = 1;
			for (i = 8; i < 16; i++) {
				u = u + (z[i] & 0xff) | 0;
				z[i] = (byte) (u & 0xff);
				u >>>= 8;
			}
			b -= 64;
			cpos += 64;
			mpos += 64;
		}
		if (b > 0) {
			crypto_core_salsa20(x, z, k, sigma);
			for (i = 0; i < b; i++)
				c[cpos + i] = (byte) ((m[mpos + i] ^ x[i]) & 0xff);
		}

		/// String dbgt = "";
		/// for (int dbg = 0; dbg < c.length-cpos; dbg ++) dbgt += " "+c[dbg +cpos];
		/// Log.d(TAG, "crypto_stream_salsa20_xor, c -> "+dbgt);

		return 0;
	}

	public static int crypto_stream_salsa20(byte[] c, int cpos, long b, byte[] n, byte[] k) {
		byte[] z = new byte[16], x = new byte[64];
		int u, i;
		for (i = 0; i < 16; i++)
			z[i] = 0;
		for (i = 0; i < 8; i++)
			z[i] = n[i];
		while (b >= 64) {
			crypto_core_salsa20(x, z, k, sigma);
			for (i = 0; i < 64; i++)
				c[cpos + i] = x[i];
			u = 1;
			for (i = 8; i < 16; i++) {
				u = u + (z[i] & 0xff) | 0;
				z[i] = (byte) (u & 0xff);
				u >>>= 8;
			}
			b -= 64;
			cpos += 64;
		}
		if (b > 0) {
			crypto_core_salsa20(x, z, k, sigma);
			for (i = 0; i < b; i++)
				c[cpos + i] = x[i];
		}

		/// String dbgt = "";
		/// for (int dbg = 0; dbg < c.length-cpos; dbg ++) dbgt += " "+c[dbg +cpos];
		/// Log.d(TAG, "crypto_stream_salsa20, c -> "+dbgt);

		return 0;
	}

	public static int crypto_stream(byte[] c, int cpos, long d, byte[] n, byte[] k) {
		byte[] s = new byte[32];
		crypto_core_hsalsa20(s, n, k, sigma);
		byte[] sn = new byte[8];
		for (int i = 0; i < 8; i++)
			sn[i] = n[i + 16];
		return crypto_stream_salsa20(c, cpos, d, sn, s);
	}

	public static int crypto_stream_xor(byte[] c, int cpos, byte[] m, int mpos, long d, byte[] n, byte[] k) {
		byte[] s = new byte[32];

		/*
		 * String dbgt = ""; for (int dbg = 0; dbg < n.length; dbg ++) dbgt +=
		 * " "+n[dbg]; Log.d(TAG, "crypto_stream_xor, nonce -> "+dbgt);
		 *
		 * dbgt = ""; for (int dbg = 0; dbg < k.length; dbg ++) dbgt += " "+k[dbg];
		 * Log.d(TAG, "crypto_stream_xor, shk -> "+dbgt);
		 */

		crypto_core_hsalsa20(s, n, k, sigma);
		byte[] sn = new byte[8];
		for (int i = 0; i < 8; i++)
			sn[i] = n[i + 16];
		return crypto_stream_salsa20_xor(c, cpos, m, mpos, d, sn, s);
	}

	/*
	 * Port of Andrew Moon's Poly1305-donna-16. Public domain.
	 * https://github.com/floodyberry/poly1305-donna
	 */
	public static final class poly1305 {

		private byte[] buffer;
		private int[] r;
		private int[] h;
		private int[] pad;
		private int leftover;
		private int fin;

		public poly1305(byte[] key) {
			this.buffer = new byte[16];
			this.r = new int[10];
			this.h = new int[10];
			this.pad = new int[8];
			this.leftover = 0;
			this.fin = 0;

			int t0, t1, t2, t3, t4, t5, t6, t7;

			t0 = key[0] & 0xff | (key[1] & 0xff) << 8;
			this.r[0] = (t0) & 0x1fff;
			t1 = key[2] & 0xff | (key[3] & 0xff) << 8;
			this.r[1] = ((t0 >>> 13) | (t1 << 3)) & 0x1fff;
			t2 = key[4] & 0xff | (key[5] & 0xff) << 8;
			this.r[2] = ((t1 >>> 10) | (t2 << 6)) & 0x1f03;
			t3 = key[6] & 0xff | (key[7] & 0xff) << 8;
			this.r[3] = ((t2 >>> 7) | (t3 << 9)) & 0x1fff;
			t4 = key[8] & 0xff | (key[9] & 0xff) << 8;
			this.r[4] = ((t3 >>> 4) | (t4 << 12)) & 0x00ff;
			this.r[5] = ((t4 >>> 1)) & 0x1ffe;
			t5 = key[10] & 0xff | (key[11] & 0xff) << 8;
			this.r[6] = ((t4 >>> 14) | (t5 << 2)) & 0x1fff;
			t6 = key[12] & 0xff | (key[13] & 0xff) << 8;
			this.r[7] = ((t5 >>> 11) | (t6 << 5)) & 0x1f81;
			t7 = key[14] & 0xff | (key[15] & 0xff) << 8;
			this.r[8] = ((t6 >>> 8) | (t7 << 8)) & 0x1fff;
			this.r[9] = ((t7 >>> 5)) & 0x007f;

			this.pad[0] = key[16] & 0xff | (key[17] & 0xff) << 8;
			this.pad[1] = key[18] & 0xff | (key[19] & 0xff) << 8;
			this.pad[2] = key[20] & 0xff | (key[21] & 0xff) << 8;
			this.pad[3] = key[22] & 0xff | (key[23] & 0xff) << 8;
			this.pad[4] = key[24] & 0xff | (key[25] & 0xff) << 8;
			this.pad[5] = key[26] & 0xff | (key[27] & 0xff) << 8;
			this.pad[6] = key[28] & 0xff | (key[29] & 0xff) << 8;
			this.pad[7] = key[30] & 0xff | (key[31] & 0xff) << 8;
		}

		public poly1305 blocks(byte[] m, int mpos, int bytes) {
			int hibit = this.fin != 0 ? 0 : (1 << 11);
			int t0, t1, t2, t3, t4, t5, t6, t7, c;
			int d0, d1, d2, d3, d4, d5, d6, d7, d8, d9;

			int h0 = this.h[0], h1 = this.h[1], h2 = this.h[2], h3 = this.h[3], h4 = this.h[4], h5 = this.h[5],
					h6 = this.h[6], h7 = this.h[7], h8 = this.h[8], h9 = this.h[9];

			int r0 = this.r[0], r1 = this.r[1], r2 = this.r[2], r3 = this.r[3], r4 = this.r[4], r5 = this.r[5],
					r6 = this.r[6], r7 = this.r[7], r8 = this.r[8], r9 = this.r[9];

			while (bytes >= 16) {
				t0 = m[mpos + 0] & 0xff | (m[mpos + 1] & 0xff) << 8;
				h0 += (t0) & 0x1fff;
				t1 = m[mpos + 2] & 0xff | (m[mpos + 3] & 0xff) << 8;
				h1 += ((t0 >>> 13) | (t1 << 3)) & 0x1fff;
				t2 = m[mpos + 4] & 0xff | (m[mpos + 5] & 0xff) << 8;
				h2 += ((t1 >>> 10) | (t2 << 6)) & 0x1fff;
				t3 = m[mpos + 6] & 0xff | (m[mpos + 7] & 0xff) << 8;
				h3 += ((t2 >>> 7) | (t3 << 9)) & 0x1fff;
				t4 = m[mpos + 8] & 0xff | (m[mpos + 9] & 0xff) << 8;
				h4 += ((t3 >>> 4) | (t4 << 12)) & 0x1fff;
				h5 += ((t4 >>> 1)) & 0x1fff;
				t5 = m[mpos + 10] & 0xff | (m[mpos + 11] & 0xff) << 8;
				h6 += ((t4 >>> 14) | (t5 << 2)) & 0x1fff;
				t6 = m[mpos + 12] & 0xff | (m[mpos + 13] & 0xff) << 8;
				h7 += ((t5 >>> 11) | (t6 << 5)) & 0x1fff;
				t7 = m[mpos + 14] & 0xff | (m[mpos + 15] & 0xff) << 8;
				h8 += ((t6 >>> 8) | (t7 << 8)) & 0x1fff;
				h9 += ((t7 >>> 5)) | hibit;

				c = 0;

				d0 = c;
				d0 += h0 * r0;
				d0 += h1 * (5 * r9);
				d0 += h2 * (5 * r8);
				d0 += h3 * (5 * r7);
				d0 += h4 * (5 * r6);
				c = (d0 >>> 13);
				d0 &= 0x1fff;
				d0 += h5 * (5 * r5);
				d0 += h6 * (5 * r4);
				d0 += h7 * (5 * r3);
				d0 += h8 * (5 * r2);
				d0 += h9 * (5 * r1);
				c += (d0 >>> 13);
				d0 &= 0x1fff;

				d1 = c;
				d1 += h0 * r1;
				d1 += h1 * r0;
				d1 += h2 * (5 * r9);
				d1 += h3 * (5 * r8);
				d1 += h4 * (5 * r7);
				c = (d1 >>> 13);
				d1 &= 0x1fff;
				d1 += h5 * (5 * r6);
				d1 += h6 * (5 * r5);
				d1 += h7 * (5 * r4);
				d1 += h8 * (5 * r3);
				d1 += h9 * (5 * r2);
				c += (d1 >>> 13);
				d1 &= 0x1fff;

				d2 = c;
				d2 += h0 * r2;
				d2 += h1 * r1;
				d2 += h2 * r0;
				d2 += h3 * (5 * r9);
				d2 += h4 * (5 * r8);
				c = (d2 >>> 13);
				d2 &= 0x1fff;
				d2 += h5 * (5 * r7);
				d2 += h6 * (5 * r6);
				d2 += h7 * (5 * r5);
				d2 += h8 * (5 * r4);
				d2 += h9 * (5 * r3);
				c += (d2 >>> 13);
				d2 &= 0x1fff;

				d3 = c;
				d3 += h0 * r3;
				d3 += h1 * r2;
				d3 += h2 * r1;
				d3 += h3 * r0;
				d3 += h4 * (5 * r9);
				c = (d3 >>> 13);
				d3 &= 0x1fff;
				d3 += h5 * (5 * r8);
				d3 += h6 * (5 * r7);
				d3 += h7 * (5 * r6);
				d3 += h8 * (5 * r5);
				d3 += h9 * (5 * r4);
				c += (d3 >>> 13);
				d3 &= 0x1fff;

				d4 = c;
				d4 += h0 * r4;
				d4 += h1 * r3;
				d4 += h2 * r2;
				d4 += h3 * r1;
				d4 += h4 * r0;
				c = (d4 >>> 13);
				d4 &= 0x1fff;
				d4 += h5 * (5 * r9);
				d4 += h6 * (5 * r8);
				d4 += h7 * (5 * r7);
				d4 += h8 * (5 * r6);
				d4 += h9 * (5 * r5);
				c += (d4 >>> 13);
				d4 &= 0x1fff;

				d5 = c;
				d5 += h0 * r5;
				d5 += h1 * r4;
				d5 += h2 * r3;
				d5 += h3 * r2;
				d5 += h4 * r1;
				c = (d5 >>> 13);
				d5 &= 0x1fff;
				d5 += h5 * r0;
				d5 += h6 * (5 * r9);
				d5 += h7 * (5 * r8);
				d5 += h8 * (5 * r7);
				d5 += h9 * (5 * r6);
				c += (d5 >>> 13);
				d5 &= 0x1fff;

				d6 = c;
				d6 += h0 * r6;
				d6 += h1 * r5;
				d6 += h2 * r4;
				d6 += h3 * r3;
				d6 += h4 * r2;
				c = (d6 >>> 13);
				d6 &= 0x1fff;
				d6 += h5 * r1;
				d6 += h6 * r0;
				d6 += h7 * (5 * r9);
				d6 += h8 * (5 * r8);
				d6 += h9 * (5 * r7);
				c += (d6 >>> 13);
				d6 &= 0x1fff;

				d7 = c;
				d7 += h0 * r7;
				d7 += h1 * r6;
				d7 += h2 * r5;
				d7 += h3 * r4;
				d7 += h4 * r3;
				c = (d7 >>> 13);
				d7 &= 0x1fff;
				d7 += h5 * r2;
				d7 += h6 * r1;
				d7 += h7 * r0;
				d7 += h8 * (5 * r9);
				d7 += h9 * (5 * r8);
				c += (d7 >>> 13);
				d7 &= 0x1fff;

				d8 = c;
				d8 += h0 * r8;
				d8 += h1 * r7;
				d8 += h2 * r6;
				d8 += h3 * r5;
				d8 += h4 * r4;
				c = (d8 >>> 13);
				d8 &= 0x1fff;
				d8 += h5 * r3;
				d8 += h6 * r2;
				d8 += h7 * r1;
				d8 += h8 * r0;
				d8 += h9 * (5 * r9);
				c += (d8 >>> 13);
				d8 &= 0x1fff;

				d9 = c;
				d9 += h0 * r9;
				d9 += h1 * r8;
				d9 += h2 * r7;
				d9 += h3 * r6;
				d9 += h4 * r5;
				c = (d9 >>> 13);
				d9 &= 0x1fff;
				d9 += h5 * r4;
				d9 += h6 * r3;
				d9 += h7 * r2;
				d9 += h8 * r1;
				d9 += h9 * r0;
				c += (d9 >>> 13);
				d9 &= 0x1fff;

				c = (((c << 2) + c)) | 0;
				c = (c + d0) | 0;
				d0 = c & 0x1fff;
				c = (c >>> 13);
				d1 += c;

				h0 = d0;
				h1 = d1;
				h2 = d2;
				h3 = d3;
				h4 = d4;
				h5 = d5;
				h6 = d6;
				h7 = d7;
				h8 = d8;
				h9 = d9;

				mpos += 16;
				bytes -= 16;
			}
			this.h[0] = h0;
			this.h[1] = h1;
			this.h[2] = h2;
			this.h[3] = h3;
			this.h[4] = h4;
			this.h[5] = h5;
			this.h[6] = h6;
			this.h[7] = h7;
			this.h[8] = h8;
			this.h[9] = h9;

			return this;
		}

		public poly1305 finish(byte[] mac, int macpos) {
			int[] g = new int[10];
			int c, mask, f, i;

			if (this.leftover != 0) {
				i = this.leftover;
				this.buffer[i++] = 1;
				for (; i < 16; i++)
					this.buffer[i] = 0;
				this.fin = 1;
				this.blocks(this.buffer, 0, 16);
			}

			c = this.h[1] >>> 13;
			this.h[1] &= 0x1fff;
			for (i = 2; i < 10; i++) {
				this.h[i] += c;
				c = this.h[i] >>> 13;
				this.h[i] &= 0x1fff;
			}
			this.h[0] += (c * 5);
			c = this.h[0] >>> 13;
			this.h[0] &= 0x1fff;
			this.h[1] += c;
			c = this.h[1] >>> 13;
			this.h[1] &= 0x1fff;
			this.h[2] += c;

			g[0] = this.h[0] + 5;
			c = g[0] >>> 13;
			g[0] &= 0x1fff;
			for (i = 1; i < 10; i++) {
				g[i] = this.h[i] + c;
				c = g[i] >>> 13;
				g[i] &= 0x1fff;
			}
			g[9] -= (1 << 13);
			g[9] &= 0xffff;

			/*
			 * backport from tweetnacl-fast.js
			 * https://github.com/dchest/tweetnacl-js/releases/tag/v0.14.3 <<< "The issue
			 * was not properly detecting if st->h was >= 2^130 - 5, coupled with [testing
			 * mistake] not catching the failure. The chance of the bug affecting anything
			 * in the real world is essentially zero luckily, but it's good to have it
			 * fixed." >>>
			 */
			/// change mask = (g[9] >>> ((2 * 8) - 1)) - 1; to as
			mask = (c ^ 1) - 1;
			mask &= 0xffff;
			///////////////////////////////////////

			for (i = 0; i < 10; i++)
				g[i] &= mask;
			mask = ~mask;
			for (i = 0; i < 10; i++)
				this.h[i] = (this.h[i] & mask) | g[i];

			this.h[0] = ((this.h[0]) | (this.h[1] << 13)) & 0xffff;
			this.h[1] = ((this.h[1] >>> 3) | (this.h[2] << 10)) & 0xffff;
			this.h[2] = ((this.h[2] >>> 6) | (this.h[3] << 7)) & 0xffff;
			this.h[3] = ((this.h[3] >>> 9) | (this.h[4] << 4)) & 0xffff;
			this.h[4] = ((this.h[4] >>> 12) | (this.h[5] << 1) | (this.h[6] << 14)) & 0xffff;
			this.h[5] = ((this.h[6] >>> 2) | (this.h[7] << 11)) & 0xffff;
			this.h[6] = ((this.h[7] >>> 5) | (this.h[8] << 8)) & 0xffff;
			this.h[7] = ((this.h[8] >>> 8) | (this.h[9] << 5)) & 0xffff;

			f = this.h[0] + this.pad[0];
			this.h[0] = f & 0xffff;
			for (i = 1; i < 8; i++) {
				f = (((this.h[i] + this.pad[i]) | 0) + (f >>> 16)) | 0;
				this.h[i] = f & 0xffff;
			}

			mac[macpos + 0] = (byte) ((this.h[0] >>> 0) & 0xff);
			mac[macpos + 1] = (byte) ((this.h[0] >>> 8) & 0xff);
			mac[macpos + 2] = (byte) ((this.h[1] >>> 0) & 0xff);
			mac[macpos + 3] = (byte) ((this.h[1] >>> 8) & 0xff);
			mac[macpos + 4] = (byte) ((this.h[2] >>> 0) & 0xff);
			mac[macpos + 5] = (byte) ((this.h[2] >>> 8) & 0xff);
			mac[macpos + 6] = (byte) ((this.h[3] >>> 0) & 0xff);
			mac[macpos + 7] = (byte) ((this.h[3] >>> 8) & 0xff);
			mac[macpos + 8] = (byte) ((this.h[4] >>> 0) & 0xff);
			mac[macpos + 9] = (byte) ((this.h[4] >>> 8) & 0xff);
			mac[macpos + 10] = (byte) ((this.h[5] >>> 0) & 0xff);
			mac[macpos + 11] = (byte) ((this.h[5] >>> 8) & 0xff);
			mac[macpos + 12] = (byte) ((this.h[6] >>> 0) & 0xff);
			mac[macpos + 13] = (byte) ((this.h[6] >>> 8) & 0xff);
			mac[macpos + 14] = (byte) ((this.h[7] >>> 0) & 0xff);
			mac[macpos + 15] = (byte) ((this.h[7] >>> 8) & 0xff);

			return this;
		}

		public poly1305 update(byte[] m, int mpos, int bytes) {
			int i, want;

			if (this.leftover != 0) {
				want = (16 - this.leftover);
				if (want > bytes)
					want = bytes;
				for (i = 0; i < want; i++)
					this.buffer[this.leftover + i] = m[mpos + i];
				bytes -= want;
				mpos += want;
				this.leftover += want;
				if (this.leftover < 16)
					return this;
				this.blocks(buffer, 0, 16);
				this.leftover = 0;
			}

			if (bytes >= 16) {
				want = bytes - (bytes % 16);
				this.blocks(m, mpos, want);
				mpos += want;
				bytes -= want;
			}

			if (bytes != 0) {
				for (i = 0; i < bytes; i++)
					this.buffer[this.leftover + i] = m[mpos + i];
				this.leftover += bytes;
			}

			return this;
		}

	}

	private static int crypto_onetimeauth(byte[] out, final int outpos, byte[] m, final int mpos, int n, byte[] k) {
		poly1305 s = new poly1305(k);
		s.update(m, mpos, n);
		s.finish(out, outpos);

		/*
		 * String dbgt = ""; for (int dbg = 0; dbg < out.length-outpos; dbg ++) dbgt +=
		 * " "+out[dbg+outpos]; Log.d(TAG, "crypto_onetimeauth -> "+dbgt);
		 */

		return 0;
	}
	public static int crypto_onetimeauth(byte[] out, byte[] m, int /* long */ n, byte[] k) {
		return crypto_onetimeauth(out, 0, m, 0, n, k);
	}

	private static int crypto_onetimeauth_verify(byte[] h, final int hoff, byte[] m, final int moff, int /* long */ n,
			byte[] k) {
		byte[] x = new byte[16];
		crypto_onetimeauth(x, 0, m, moff, n, k);
		return crypto_verify_16(h, hoff, x, 0);
	}
	public static int crypto_onetimeauth_verify(byte[] h, byte[] m, int /* long */ n, byte[] k) {
		return crypto_onetimeauth_verify(h, 0, m, 0, n, k);
	}
	public static int crypto_onetimeauth_verify(byte[] h, byte[] m, byte[] k) {
		return crypto_onetimeauth_verify(h, m, m != null ? m.length : 0, k);
	}

	public static int crypto_secretbox(byte[] c, byte[] m, int /* long */ d, byte[] n, byte[] k) {
		int i;
		if (d < 32)
			return -1;
		crypto_stream_xor(c, 0, m, 0, d, n, k);
		crypto_onetimeauth(c, 16, c, 32, d - 32, c);
		/// for (i = 0; i < 16; i++) c[i] = 0;
		return 0;
	}

	public static int crypto_secretbox_open(byte[] m, byte[] c, int /* long */ d, byte[] n, byte[] k) {
		int i;
		byte[] x = new byte[32];
		if (d < 32)
			return -1;
		crypto_stream(x, 0, 32, n, k);
		if (crypto_onetimeauth_verify(c, 16, c, 32, d - 32, x) != 0)
			return -1;
		crypto_stream_xor(m, 0, c, 0, d, n, k);
		/// for (i = 0; i < 32; i++) m[i] = 0;
		return 0;
	}

	private static void set25519(long[] r, long[] a) {
		int i;
		for (i = 0; i < 16; i++)
			r[i] = a[i];
	}

	private static void car25519(long[] o) {
		int i;
		long v, c = 1;
		for (i = 0; i < 16; i++) {
			v = o[i] + c + 65535;
			c = v >> 16;
			o[i] = v - c * 65536;
		}
		o[0] += c - 1 + 37 * (c - 1);
	}

	private static void sel25519(long[] p, long[] q, int b) {
		sel25519(p, 0, q, 0, b);
	}
	private static void sel25519(long[] p, final int poff, long[] q, final int qoff, int b) {
		long t, c = ~(b - 1);
		for (int i = 0; i < 16; i++) {
			t = c & (p[i + poff] ^ q[i + qoff]);
			p[i + poff] ^= t;
			q[i + qoff] ^= t;
		}
	}

	private static void pack25519(byte[] o, long[] n, final int noff) {
		int i, j, b;
		long[] m = new long[16], t = new long[16];
		for (i = 0; i < 16; i++)
			t[i] = n[i + noff];
		car25519(t);
		car25519(t);
		car25519(t);
		for (j = 0; j < 2; j++) {
			m[0] = t[0] - 0xffed;
			for (i = 1; i < 15; i++) {
				m[i] = t[i] - 0xffff - ((m[i - 1] >> 16) & 1);
				m[i - 1] &= 0xffff;
			}
			m[15] = t[15] - 0x7fff - ((m[14] >> 16) & 1);
			b = (int) ((m[15] >> 16) & 1);
			m[14] &= 0xffff;
			sel25519(t, 0, m, 0, 1 - b);
		}
		for (i = 0; i < 16; i++) {
			o[2 * i] = (byte) (t[i] & 0xff);
			o[2 * i + 1] = (byte) (t[i] >> 8);
		}
	}

	private static int neq25519(long[] a, long[] b) {
		return neq25519(a, 0, b, 0);
	}
	private static int neq25519(long[] a, final int aoff, long[] b, final int boff) {
		byte[] c = new byte[32], d = new byte[32];
		pack25519(c, a, aoff);
		pack25519(d, b, boff);
		return crypto_verify_32(c, 0, d, 0);
	}

	private static byte par25519(long[] a) {
		return par25519(a, 0);
	}
	private static byte par25519(long[] a, final int aoff) {
		byte[] d = new byte[32];
		pack25519(d, a, aoff);
		return (byte) (d[0] & 1);
	}

	private static void unpack25519(long[] o, byte[] n) {
		int i;
		for (i = 0; i < 16; i++)
			o[i] = (n[2 * i] & 0xff) + ((long) ((n[2 * i + 1] << 8) & 0xffff));
		o[15] &= 0x7fff;
	}

	private static void A(long[] o, long[] a, long[] b) {
		A(o, 0, a, 0, b, 0);
	}
	private static void A(long[] o, final int ooff, long[] a, final int aoff, long[] b, final int boff) {
		int i;
		for (i = 0; i < 16; i++)
			o[i + ooff] = a[i + aoff] + b[i + boff];
	}

	private static void Z(long[] o, long[] a, long[] b) {
		Z(o, 0, a, 0, b, 0);
	}
	private static void Z(long[] o, final int ooff, long[] a, final int aoff, long[] b, final int boff) {
		int i;
		for (i = 0; i < 16; i++)
			o[i + ooff] = a[i + aoff] - b[i + boff];
	}

	private static void M(long[] o, long[] a, long[] b) {
		M(o, 0, a, 0, b, 0);
	}
	private static void M(long[] o, final int ooff, long[] a, final int aoff, long[] b, final int boff) {
		long v, c, t0 = 0, t1 = 0, t2 = 0, t3 = 0, t4 = 0, t5 = 0, t6 = 0, t7 = 0, t8 = 0, t9 = 0, t10 = 0, t11 = 0,
				t12 = 0, t13 = 0, t14 = 0, t15 = 0, t16 = 0, t17 = 0, t18 = 0, t19 = 0, t20 = 0, t21 = 0, t22 = 0,
				t23 = 0, t24 = 0, t25 = 0, t26 = 0, t27 = 0, t28 = 0, t29 = 0, t30 = 0, b0 = b[0 + boff],
				b1 = b[1 + boff], b2 = b[2 + boff], b3 = b[3 + boff], b4 = b[4 + boff], b5 = b[5 + boff],
				b6 = b[6 + boff], b7 = b[7 + boff], b8 = b[8 + boff], b9 = b[9 + boff], b10 = b[10 + boff],
				b11 = b[11 + boff], b12 = b[12 + boff], b13 = b[13 + boff], b14 = b[14 + boff], b15 = b[15 + boff];

		v = a[0 + aoff];
		t0 += v * b0;
		t1 += v * b1;
		t2 += v * b2;
		t3 += v * b3;
		t4 += v * b4;
		t5 += v * b5;
		t6 += v * b6;
		t7 += v * b7;
		t8 += v * b8;
		t9 += v * b9;
		t10 += v * b10;
		t11 += v * b11;
		t12 += v * b12;
		t13 += v * b13;
		t14 += v * b14;
		t15 += v * b15;
		v = a[1 + aoff];
		t1 += v * b0;
		t2 += v * b1;
		t3 += v * b2;
		t4 += v * b3;
		t5 += v * b4;
		t6 += v * b5;
		t7 += v * b6;
		t8 += v * b7;
		t9 += v * b8;
		t10 += v * b9;
		t11 += v * b10;
		t12 += v * b11;
		t13 += v * b12;
		t14 += v * b13;
		t15 += v * b14;
		t16 += v * b15;
		v = a[2 + aoff];
		t2 += v * b0;
		t3 += v * b1;
		t4 += v * b2;
		t5 += v * b3;
		t6 += v * b4;
		t7 += v * b5;
		t8 += v * b6;
		t9 += v * b7;
		t10 += v * b8;
		t11 += v * b9;
		t12 += v * b10;
		t13 += v * b11;
		t14 += v * b12;
		t15 += v * b13;
		t16 += v * b14;
		t17 += v * b15;
		v = a[3 + aoff];
		t3 += v * b0;
		t4 += v * b1;
		t5 += v * b2;
		t6 += v * b3;
		t7 += v * b4;
		t8 += v * b5;
		t9 += v * b6;
		t10 += v * b7;
		t11 += v * b8;
		t12 += v * b9;
		t13 += v * b10;
		t14 += v * b11;
		t15 += v * b12;
		t16 += v * b13;
		t17 += v * b14;
		t18 += v * b15;
		v = a[4 + aoff];
		t4 += v * b0;
		t5 += v * b1;
		t6 += v * b2;
		t7 += v * b3;
		t8 += v * b4;
		t9 += v * b5;
		t10 += v * b6;
		t11 += v * b7;
		t12 += v * b8;
		t13 += v * b9;
		t14 += v * b10;
		t15 += v * b11;
		t16 += v * b12;
		t17 += v * b13;
		t18 += v * b14;
		t19 += v * b15;
		v = a[5 + aoff];
		t5 += v * b0;
		t6 += v * b1;
		t7 += v * b2;
		t8 += v * b3;
		t9 += v * b4;
		t10 += v * b5;
		t11 += v * b6;
		t12 += v * b7;
		t13 += v * b8;
		t14 += v * b9;
		t15 += v * b10;
		t16 += v * b11;
		t17 += v * b12;
		t18 += v * b13;
		t19 += v * b14;
		t20 += v * b15;
		v = a[6 + aoff];
		t6 += v * b0;
		t7 += v * b1;
		t8 += v * b2;
		t9 += v * b3;
		t10 += v * b4;
		t11 += v * b5;
		t12 += v * b6;
		t13 += v * b7;
		t14 += v * b8;
		t15 += v * b9;
		t16 += v * b10;
		t17 += v * b11;
		t18 += v * b12;
		t19 += v * b13;
		t20 += v * b14;
		t21 += v * b15;
		v = a[7 + aoff];
		t7 += v * b0;
		t8 += v * b1;
		t9 += v * b2;
		t10 += v * b3;
		t11 += v * b4;
		t12 += v * b5;
		t13 += v * b6;
		t14 += v * b7;
		t15 += v * b8;
		t16 += v * b9;
		t17 += v * b10;
		t18 += v * b11;
		t19 += v * b12;
		t20 += v * b13;
		t21 += v * b14;
		t22 += v * b15;
		v = a[8 + aoff];
		t8 += v * b0;
		t9 += v * b1;
		t10 += v * b2;
		t11 += v * b3;
		t12 += v * b4;
		t13 += v * b5;
		t14 += v * b6;
		t15 += v * b7;
		t16 += v * b8;
		t17 += v * b9;
		t18 += v * b10;
		t19 += v * b11;
		t20 += v * b12;
		t21 += v * b13;
		t22 += v * b14;
		t23 += v * b15;
		v = a[9 + aoff];
		t9 += v * b0;
		t10 += v * b1;
		t11 += v * b2;
		t12 += v * b3;
		t13 += v * b4;
		t14 += v * b5;
		t15 += v * b6;
		t16 += v * b7;
		t17 += v * b8;
		t18 += v * b9;
		t19 += v * b10;
		t20 += v * b11;
		t21 += v * b12;
		t22 += v * b13;
		t23 += v * b14;
		t24 += v * b15;
		v = a[10 + aoff];
		t10 += v * b0;
		t11 += v * b1;
		t12 += v * b2;
		t13 += v * b3;
		t14 += v * b4;
		t15 += v * b5;
		t16 += v * b6;
		t17 += v * b7;
		t18 += v * b8;
		t19 += v * b9;
		t20 += v * b10;
		t21 += v * b11;
		t22 += v * b12;
		t23 += v * b13;
		t24 += v * b14;
		t25 += v * b15;
		v = a[11 + aoff];
		t11 += v * b0;
		t12 += v * b1;
		t13 += v * b2;
		t14 += v * b3;
		t15 += v * b4;
		t16 += v * b5;
		t17 += v * b6;
		t18 += v * b7;
		t19 += v * b8;
		t20 += v * b9;
		t21 += v * b10;
		t22 += v * b11;
		t23 += v * b12;
		t24 += v * b13;
		t25 += v * b14;
		t26 += v * b15;
		v = a[12 + aoff];
		t12 += v * b0;
		t13 += v * b1;
		t14 += v * b2;
		t15 += v * b3;
		t16 += v * b4;
		t17 += v * b5;
		t18 += v * b6;
		t19 += v * b7;
		t20 += v * b8;
		t21 += v * b9;
		t22 += v * b10;
		t23 += v * b11;
		t24 += v * b12;
		t25 += v * b13;
		t26 += v * b14;
		t27 += v * b15;
		v = a[13 + aoff];
		t13 += v * b0;
		t14 += v * b1;
		t15 += v * b2;
		t16 += v * b3;
		t17 += v * b4;
		t18 += v * b5;
		t19 += v * b6;
		t20 += v * b7;
		t21 += v * b8;
		t22 += v * b9;
		t23 += v * b10;
		t24 += v * b11;
		t25 += v * b12;
		t26 += v * b13;
		t27 += v * b14;
		t28 += v * b15;
		v = a[14 + aoff];
		t14 += v * b0;
		t15 += v * b1;
		t16 += v * b2;
		t17 += v * b3;
		t18 += v * b4;
		t19 += v * b5;
		t20 += v * b6;
		t21 += v * b7;
		t22 += v * b8;
		t23 += v * b9;
		t24 += v * b10;
		t25 += v * b11;
		t26 += v * b12;
		t27 += v * b13;
		t28 += v * b14;
		t29 += v * b15;
		v = a[15 + aoff];
		t15 += v * b0;
		t16 += v * b1;
		t17 += v * b2;
		t18 += v * b3;
		t19 += v * b4;
		t20 += v * b5;
		t21 += v * b6;
		t22 += v * b7;
		t23 += v * b8;
		t24 += v * b9;
		t25 += v * b10;
		t26 += v * b11;
		t27 += v * b12;
		t28 += v * b13;
		t29 += v * b14;
		t30 += v * b15;

		t0 += 38 * t16;
		t1 += 38 * t17;
		t2 += 38 * t18;
		t3 += 38 * t19;
		t4 += 38 * t20;
		t5 += 38 * t21;
		t6 += 38 * t22;
		t7 += 38 * t23;
		t8 += 38 * t24;
		t9 += 38 * t25;
		t10 += 38 * t26;
		t11 += 38 * t27;
		t12 += 38 * t28;
		t13 += 38 * t29;
		t14 += 38 * t30;
		// t15 left as is

		// first car
		c = 1;
		v = t0 + c + 65535;
		c = v >> 16;
		t0 = v - c * 65536;
		v = t1 + c + 65535;
		c = v >> 16;
		t1 = v - c * 65536;
		v = t2 + c + 65535;
		c = v >> 16;
		t2 = v - c * 65536;
		v = t3 + c + 65535;
		c = v >> 16;
		t3 = v - c * 65536;
		v = t4 + c + 65535;
		c = v >> 16;
		t4 = v - c * 65536;
		v = t5 + c + 65535;
		c = v >> 16;
		t5 = v - c * 65536;
		v = t6 + c + 65535;
		c = v >> 16;
		t6 = v - c * 65536;
		v = t7 + c + 65535;
		c = v >> 16;
		t7 = v - c * 65536;
		v = t8 + c + 65535;
		c = v >> 16;
		t8 = v - c * 65536;
		v = t9 + c + 65535;
		c = v >> 16;
		t9 = v - c * 65536;
		v = t10 + c + 65535;
		c = v >> 16;
		t10 = v - c * 65536;
		v = t11 + c + 65535;
		c = v >> 16;
		t11 = v - c * 65536;
		v = t12 + c + 65535;
		c = v >> 16;
		t12 = v - c * 65536;
		v = t13 + c + 65535;
		c = v >> 16;
		t13 = v - c * 65536;
		v = t14 + c + 65535;
		c = v >> 16;
		t14 = v - c * 65536;
		v = t15 + c + 65535;
		c = v >> 16;
		t15 = v - c * 65536;
		t0 += c - 1 + 37 * (c - 1);

		// second car
		c = 1;
		v = t0 + c + 65535;
		c = v >> 16;
		t0 = v - c * 65536;
		v = t1 + c + 65535;
		c = v >> 16;
		t1 = v - c * 65536;
		v = t2 + c + 65535;
		c = v >> 16;
		t2 = v - c * 65536;
		v = t3 + c + 65535;
		c = v >> 16;
		t3 = v - c * 65536;
		v = t4 + c + 65535;
		c = v >> 16;
		t4 = v - c * 65536;
		v = t5 + c + 65535;
		c = v >> 16;
		t5 = v - c * 65536;
		v = t6 + c + 65535;
		c = v >> 16;
		t6 = v - c * 65536;
		v = t7 + c + 65535;
		c = v >> 16;
		t7 = v - c * 65536;
		v = t8 + c + 65535;
		c = v >> 16;
		t8 = v - c * 65536;
		v = t9 + c + 65535;
		c = v >> 16;
		t9 = v - c * 65536;
		v = t10 + c + 65535;
		c = v >> 16;
		t10 = v - c * 65536;
		v = t11 + c + 65535;
		c = v >> 16;
		t11 = v - c * 65536;
		v = t12 + c + 65535;
		c = v >> 16;
		t12 = v - c * 65536;
		v = t13 + c + 65535;
		c = v >> 16;
		t13 = v - c * 65536;
		v = t14 + c + 65535;
		c = v >> 16;
		t14 = v - c * 65536;
		v = t15 + c + 65535;
		c = v >> 16;
		t15 = v - c * 65536;
		t0 += c - 1 + 37 * (c - 1);

		o[0 + ooff] = t0;
		o[1 + ooff] = t1;
		o[2 + ooff] = t2;
		o[3 + ooff] = t3;
		o[4 + ooff] = t4;
		o[5 + ooff] = t5;
		o[6 + ooff] = t6;
		o[7 + ooff] = t7;
		o[8 + ooff] = t8;
		o[9 + ooff] = t9;
		o[10 + ooff] = t10;
		o[11 + ooff] = t11;
		o[12 + ooff] = t12;
		o[13 + ooff] = t13;
		o[14 + ooff] = t14;
		o[15 + ooff] = t15;
	}

	private static void S(long[] o, long[] a) {
		S(o, 0, a, 0);
	}
	private static void S(long[] o, final int ooff, long[] a, final int aoff) {
		M(o, ooff, a, aoff, a, aoff);
	}

	private static void inv25519(long[] o, final int ooff, long[] i, final int ioff) {
		long[] c = new long[16];
		int a;
		for (a = 0; a < 16; a++)
			c[a] = i[a + ioff];
		for (a = 253; a >= 0; a--) {
			S(c, 0, c, 0);
			if (a != 2 && a != 4)
				M(c, 0, c, 0, i, ioff);
		}
		for (a = 0; a < 16; a++)
			o[a + ooff] = c[a];
	}

	private static void pow2523(long[] o, long[] i) {
		long[] c = new long[16];
		int a;

		for (a = 0; a < 16; a++)
			c[a] = i[a];

		for (a = 250; a >= 0; a--) {
			S(c, 0, c, 0);
			if (a != 1)
				M(c, 0, c, 0, i, 0);
		}

		for (a = 0; a < 16; a++)
			o[a] = c[a];
	}

	public static int crypto_scalarmult(byte[] q, byte[] n, byte[] p) {
		byte[] z = new byte[32];
		long[] x = new long[80];
		int r, i;
		long[] a = new long[16], b = new long[16], c = new long[16], d = new long[16], e = new long[16],
				f = new long[16];
		for (i = 0; i < 31; i++)
			z[i] = n[i];
		z[31] = (byte) (((n[31] & 127) | 64) & 0xff);
		z[0] &= 248;
		unpack25519(x, p);
		for (i = 0; i < 16; i++) {
			b[i] = x[i];
			d[i] = a[i] = c[i] = 0;
		}
		a[0] = d[0] = 1;
		for (i = 254; i >= 0; --i) {
			r = (z[i >>> 3] >>> (i & 7)) & 1;
			sel25519(a, b, r);
			sel25519(c, d, r);
			A(e, a, c);
			Z(a, a, c);
			A(c, b, d);
			Z(b, b, d);
			S(d, e);
			S(f, a);
			M(a, c, a);
			M(c, b, e);
			A(e, a, c);
			Z(a, a, c);
			S(b, a);
			Z(c, d, f);
			M(a, c, _121665);
			A(a, a, d);
			M(c, c, a);
			M(a, d, f);
			M(d, b, x);
			S(b, e);
			sel25519(a, b, r);
			sel25519(c, d, r);
		}
		for (i = 0; i < 16; i++) {
			x[i + 16] = a[i];
			x[i + 32] = c[i];
			x[i + 48] = b[i];
			x[i + 64] = d[i];
		}
		inv25519(x, 32, x, 32);
		M(x, 16, x, 16, x, 32);
		pack25519(q, x, 16);

		return 0;
	}

	public static int crypto_scalarmult_base(byte[] q, byte[] n) {
		return crypto_scalarmult(q, n, _9);
	}

	public static int crypto_box_keypair(byte[] y, byte[] x) {
		randombytes(x, 32);
		return crypto_scalarmult_base(y, x);
	}

	public static int crypto_box_beforenm(byte[] k, byte[] y, byte[] x) {
		byte[] s = new byte[32];
		crypto_scalarmult(s, x, y);

		/*
		 * String dbgt = ""; for (int dbg = 0; dbg < s.length; dbg ++) dbgt +=
		 * " "+s[dbg]; Log.d(TAG, "crypto_box_beforenm -> "+dbgt);
		 *
		 * dbgt = ""; for (int dbg = 0; dbg < x.length; dbg ++) dbgt += " "+x[dbg];
		 * Log.d(TAG, "crypto_box_beforenm, x -> "+dbgt);
		 *
		 * dbgt = ""; for (int dbg = 0; dbg < y.length; dbg ++) dbgt += " "+y[dbg];
		 * Log.d(TAG, "crypto_box_beforenm, y -> "+dbgt);
		 */

		return crypto_core_hsalsa20(k, _0, s, sigma);
	}

	public static int crypto_box_afternm(byte[] c, byte[] m, int /* long */ d, byte[] n, byte[] k) {
		return crypto_secretbox(c, m, d, n, k);
	}

	public static int crypto_box_open_afternm(byte[] m, byte[] c, int /* long */ d, byte[] n, byte[] k) {
		return crypto_secretbox_open(m, c, d, n, k);
	}

	public static int crypto_box(byte[] c, byte[] m, int /* long */ d, byte[] n, byte[] y, byte[] x) {
		byte[] k = new byte[32];

		/// L/og.d(TAG, "crypto_box start ...");

		crypto_box_beforenm(k, y, x);
		return crypto_box_afternm(c, m, d, n, k);
	}

	public static int crypto_box_open(byte[] m, byte[] c, int /* long */ d, byte[] n, byte[] y, byte[] x) {
		byte[] k = new byte[32];
		crypto_box_beforenm(k, y, x);
		return crypto_box_open_afternm(m, c, d, n, k);
	}

	private static final long K[] = {0x428a2f98d728ae22L, 0x7137449123ef65cdL, 0xb5c0fbcfec4d3b2fL, 0xe9b5dba58189dbbcL,
			0x3956c25bf348b538L, 0x59f111f1b605d019L, 0x923f82a4af194f9bL, 0xab1c5ed5da6d8118L, 0xd807aa98a3030242L,
			0x12835b0145706fbeL, 0x243185be4ee4b28cL, 0x550c7dc3d5ffb4e2L, 0x72be5d74f27b896fL, 0x80deb1fe3b1696b1L,
			0x9bdc06a725c71235L, 0xc19bf174cf692694L, 0xe49b69c19ef14ad2L, 0xefbe4786384f25e3L, 0x0fc19dc68b8cd5b5L,
			0x240ca1cc77ac9c65L, 0x2de92c6f592b0275L, 0x4a7484aa6ea6e483L, 0x5cb0a9dcbd41fbd4L, 0x76f988da831153b5L,
			0x983e5152ee66dfabL, 0xa831c66d2db43210L, 0xb00327c898fb213fL, 0xbf597fc7beef0ee4L, 0xc6e00bf33da88fc2L,
			0xd5a79147930aa725L, 0x06ca6351e003826fL, 0x142929670a0e6e70L, 0x27b70a8546d22ffcL, 0x2e1b21385c26c926L,
			0x4d2c6dfc5ac42aedL, 0x53380d139d95b3dfL, 0x650a73548baf63deL, 0x766a0abb3c77b2a8L, 0x81c2c92e47edaee6L,
			0x92722c851482353bL, 0xa2bfe8a14cf10364L, 0xa81a664bbc423001L, 0xc24b8b70d0f89791L, 0xc76c51a30654be30L,
			0xd192e819d6ef5218L, 0xd69906245565a910L, 0xf40e35855771202aL, 0x106aa07032bbd1b8L, 0x19a4c116b8d2d0c8L,
			0x1e376c085141ab53L, 0x2748774cdf8eeb99L, 0x34b0bcb5e19b48a8L, 0x391c0cb3c5c95a63L, 0x4ed8aa4ae3418acbL,
			0x5b9cca4f7763e373L, 0x682e6ff3d6b2b8a3L, 0x748f82ee5defb2fcL, 0x78a5636f43172f60L, 0x84c87814a1f0ab72L,
			0x8cc702081a6439ecL, 0x90befffa23631e28L, 0xa4506cebde82bde9L, 0xbef9a3f7b2c67915L, 0xc67178f2e372532bL,
			0xca273eceea26619cL, 0xd186b8c721c0c207L, 0xeada7dd6cde0eb1eL, 0xf57d4f7fee6ed178L, 0x06f067aa72176fbaL,
			0x0a637dc5a2c898a6L, 0x113f9804bef90daeL, 0x1b710b35131c471bL, 0x28db77f523047d84L, 0x32caab7b40c72493L,
			0x3c9ebe0a15c9bebcL, 0x431d67c49c100d4cL, 0x4cc5d4becb3e42b6L, 0x597f299cfc657e2aL, 0x5fcb6fab3ad6faecL,
			0x6c44198c4a475817L};

	private static int crypto_hashblocks_hl(int[] hh, int[] hl, byte[] m, final int moff, int n) {

		/// String dbgt = "";
		/// for (int dbg = 0; dbg < n; dbg ++) dbgt += " "+m[dbg+moff];
		/// Log.d(TAG, "crypto_hashblocks_hl m/"+n + "-> "+dbgt);

		int[] wh = new int[16], wl = new int[16];
		int bh0, bh1, bh2, bh3, bh4, bh5, bh6, bh7, bl0, bl1, bl2, bl3, bl4, bl5, bl6, bl7, th, tl, h, l, i, j, a, b, c,
				d;

		int ah0 = hh[0], ah1 = hh[1], ah2 = hh[2], ah3 = hh[3], ah4 = hh[4], ah5 = hh[5], ah6 = hh[6], ah7 = hh[7],

				al0 = hl[0], al1 = hl[1], al2 = hl[2], al3 = hl[3], al4 = hl[4], al5 = hl[5], al6 = hl[6], al7 = hl[7];

		int pos = 0;
		while (n >= 128) {
			for (i = 0; i < 16; i++) {
				j = 8 * i + pos;
				wh[i] = ((m[j + 0 + moff] & 0xff) << 24) | ((m[j + 1 + moff] & 0xff) << 16)
						| ((m[j + 2 + moff] & 0xff) << 8) | ((m[j + 3 + moff] & 0xff) << 0);
				wl[i] = ((m[j + 4 + moff] & 0xff) << 24) | ((m[j + 5 + moff] & 0xff) << 16)
						| ((m[j + 6 + moff] & 0xff) << 8) | ((m[j + 7 + moff] & 0xff) << 0);
			}
			for (i = 0; i < 80; i++) {
				bh0 = ah0;
				bh1 = ah1;
				bh2 = ah2;
				bh3 = ah3;
				bh4 = ah4;
				bh5 = ah5;
				bh6 = ah6;
				bh7 = ah7;

				bl0 = al0;
				bl1 = al1;
				bl2 = al2;
				bl3 = al3;
				bl4 = al4;
				bl5 = al5;
				bl6 = al6;
				bl7 = al7;

				// add
				h = ah7;
				l = al7;

				a = l & 0xffff;
				b = l >>> 16;
				c = h & 0xffff;
				d = h >>> 16;

				// Sigma1
				h = ((ah4 >>> 14) | (al4 << (32 - 14))) ^ ((ah4 >>> 18) | (al4 << (32 - 18)))
						^ ((al4 >>> (41 - 32)) | (ah4 << (32 - (41 - 32))));
				l = ((al4 >>> 14) | (ah4 << (32 - 14))) ^ ((al4 >>> 18) | (ah4 << (32 - 18)))
						^ ((ah4 >>> (41 - 32)) | (al4 << (32 - (41 - 32))));

				a += l & 0xffff;
				b += l >>> 16;
				c += h & 0xffff;
				d += h >>> 16;

				// Ch
				h = (ah4 & ah5) ^ (~ah4 & ah6);
				l = (al4 & al5) ^ (~al4 & al6);

				a += l & 0xffff;
				b += l >>> 16;
				c += h & 0xffff;
				d += h >>> 16;

				// K
				/// h = K[i*2];
				/// l = K[i*2+1];
				h = (int) ((K[i] >>> 32) & 0xffffffff);
				l = (int) ((K[i] >>> 0) & 0xffffffff);

				/// Log.d(TAG, "i"+i + ",h:0x"+Integer.toHexString(h) +
				/// ",l:0x"+Integer.toHexString(l));

				a += l & 0xffff;
				b += l >>> 16;
				c += h & 0xffff;
				d += h >>> 16;

				// w
				h = wh[i % 16];
				l = wl[i % 16];

				a += l & 0xffff;
				b += l >>> 16;
				c += h & 0xffff;
				d += h >>> 16;

				b += a >>> 16;
				c += b >>> 16;
				d += c >>> 16;

				th = c & 0xffff | d << 16;
				tl = a & 0xffff | b << 16;

				// add
				h = th;
				l = tl;

				a = l & 0xffff;
				b = l >>> 16;
				c = h & 0xffff;
				d = h >>> 16;

				// Sigma0
				h = ((ah0 >>> 28) | (al0 << (32 - 28))) ^ ((al0 >>> (34 - 32)) | (ah0 << (32 - (34 - 32))))
						^ ((al0 >>> (39 - 32)) | (ah0 << (32 - (39 - 32))));
				l = ((al0 >>> 28) | (ah0 << (32 - 28))) ^ ((ah0 >>> (34 - 32)) | (al0 << (32 - (34 - 32))))
						^ ((ah0 >>> (39 - 32)) | (al0 << (32 - (39 - 32))));

				a += l & 0xffff;
				b += l >>> 16;
				c += h & 0xffff;
				d += h >>> 16;

				// Maj
				h = (ah0 & ah1) ^ (ah0 & ah2) ^ (ah1 & ah2);
				l = (al0 & al1) ^ (al0 & al2) ^ (al1 & al2);

				a += l & 0xffff;
				b += l >>> 16;
				c += h & 0xffff;
				d += h >>> 16;

				b += a >>> 16;
				c += b >>> 16;
				d += c >>> 16;

				bh7 = (c & 0xffff) | (d << 16);
				bl7 = (a & 0xffff) | (b << 16);

				// add
				h = bh3;
				l = bl3;

				a = l & 0xffff;
				b = l >>> 16;
				c = h & 0xffff;
				d = h >>> 16;

				h = th;
				l = tl;

				a += l & 0xffff;
				b += l >>> 16;
				c += h & 0xffff;
				d += h >>> 16;

				b += a >>> 16;
				c += b >>> 16;
				d += c >>> 16;

				bh3 = (c & 0xffff) | (d << 16);
				bl3 = (a & 0xffff) | (b << 16);

				ah1 = bh0;
				ah2 = bh1;
				ah3 = bh2;
				ah4 = bh3;
				ah5 = bh4;
				ah6 = bh5;
				ah7 = bh6;
				ah0 = bh7;

				al1 = bl0;
				al2 = bl1;
				al3 = bl2;
				al4 = bl3;
				al5 = bl4;
				al6 = bl5;
				al7 = bl6;
				al0 = bl7;

				if (i % 16 == 15) {
					for (j = 0; j < 16; j++) {
						// add
						h = wh[j];
						l = wl[j];

						a = l & 0xffff;
						b = l >>> 16;
						c = h & 0xffff;
						d = h >>> 16;

						h = wh[(j + 9) % 16];
						l = wl[(j + 9) % 16];

						a += l & 0xffff;
						b += l >>> 16;
						c += h & 0xffff;
						d += h >>> 16;

						// sigma0
						th = wh[(j + 1) % 16];
						tl = wl[(j + 1) % 16];
						h = ((th >>> 1) | (tl << (32 - 1))) ^ ((th >>> 8) | (tl << (32 - 8))) ^ (th >>> 7);
						l = ((tl >>> 1) | (th << (32 - 1))) ^ ((tl >>> 8) | (th << (32 - 8)))
								^ ((tl >>> 7) | (th << (32 - 7)));

						a += l & 0xffff;
						b += l >>> 16;
						c += h & 0xffff;
						d += h >>> 16;

						// sigma1
						th = wh[(j + 14) % 16];
						tl = wl[(j + 14) % 16];
						h = ((th >>> 19) | (tl << (32 - 19))) ^ ((tl >>> (61 - 32)) | (th << (32 - (61 - 32))))
								^ (th >>> 6);
						l = ((tl >>> 19) | (th << (32 - 19))) ^ ((th >>> (61 - 32)) | (tl << (32 - (61 - 32))))
								^ ((tl >>> 6) | (th << (32 - 6)));

						a += l & 0xffff;
						b += l >>> 16;
						c += h & 0xffff;
						d += h >>> 16;

						b += a >>> 16;
						c += b >>> 16;
						d += c >>> 16;

						wh[j] = (c & 0xffff) | (d << 16);
						wl[j] = (a & 0xffff) | (b << 16);
					}
				}
			}

			// add
			h = ah0;
			l = al0;

			a = l & 0xffff;
			b = l >>> 16;
			c = h & 0xffff;
			d = h >>> 16;

			h = hh[0];
			l = hl[0];

			a += l & 0xffff;
			b += l >>> 16;
			c += h & 0xffff;
			d += h >>> 16;

			b += a >>> 16;
			c += b >>> 16;
			d += c >>> 16;

			hh[0] = ah0 = (c & 0xffff) | (d << 16);
			hl[0] = al0 = (a & 0xffff) | (b << 16);

			h = ah1;
			l = al1;

			a = l & 0xffff;
			b = l >>> 16;
			c = h & 0xffff;
			d = h >>> 16;

			h = hh[1];
			l = hl[1];

			a += l & 0xffff;
			b += l >>> 16;
			c += h & 0xffff;
			d += h >>> 16;

			b += a >>> 16;
			c += b >>> 16;
			d += c >>> 16;

			hh[1] = ah1 = (c & 0xffff) | (d << 16);
			hl[1] = al1 = (a & 0xffff) | (b << 16);

			h = ah2;
			l = al2;

			a = l & 0xffff;
			b = l >>> 16;
			c = h & 0xffff;
			d = h >>> 16;

			h = hh[2];
			l = hl[2];

			a += l & 0xffff;
			b += l >>> 16;
			c += h & 0xffff;
			d += h >>> 16;

			b += a >>> 16;
			c += b >>> 16;
			d += c >>> 16;

			hh[2] = ah2 = (c & 0xffff) | (d << 16);
			hl[2] = al2 = (a & 0xffff) | (b << 16);

			h = ah3;
			l = al3;

			a = l & 0xffff;
			b = l >>> 16;
			c = h & 0xffff;
			d = h >>> 16;

			h = hh[3];
			l = hl[3];

			a += l & 0xffff;
			b += l >>> 16;
			c += h & 0xffff;
			d += h >>> 16;

			b += a >>> 16;
			c += b >>> 16;
			d += c >>> 16;

			hh[3] = ah3 = (c & 0xffff) | (d << 16);
			hl[3] = al3 = (a & 0xffff) | (b << 16);

			h = ah4;
			l = al4;

			a = l & 0xffff;
			b = l >>> 16;
			c = h & 0xffff;
			d = h >>> 16;

			h = hh[4];
			l = hl[4];

			a += l & 0xffff;
			b += l >>> 16;
			c += h & 0xffff;
			d += h >>> 16;

			b += a >>> 16;
			c += b >>> 16;
			d += c >>> 16;

			hh[4] = ah4 = (c & 0xffff) | (d << 16);
			hl[4] = al4 = (a & 0xffff) | (b << 16);

			h = ah5;
			l = al5;

			a = l & 0xffff;
			b = l >>> 16;
			c = h & 0xffff;
			d = h >>> 16;

			h = hh[5];
			l = hl[5];

			a += l & 0xffff;
			b += l >>> 16;
			c += h & 0xffff;
			d += h >>> 16;

			b += a >>> 16;
			c += b >>> 16;
			d += c >>> 16;

			hh[5] = ah5 = (c & 0xffff) | (d << 16);
			hl[5] = al5 = (a & 0xffff) | (b << 16);

			h = ah6;
			l = al6;

			a = l & 0xffff;
			b = l >>> 16;
			c = h & 0xffff;
			d = h >>> 16;

			h = hh[6];
			l = hl[6];

			a += l & 0xffff;
			b += l >>> 16;
			c += h & 0xffff;
			d += h >>> 16;

			b += a >>> 16;
			c += b >>> 16;
			d += c >>> 16;

			hh[6] = ah6 = (c & 0xffff) | (d << 16);
			hl[6] = al6 = (a & 0xffff) | (b << 16);

			h = ah7;
			l = al7;

			a = l & 0xffff;
			b = l >>> 16;
			c = h & 0xffff;
			d = h >>> 16;

			h = hh[7];
			l = hl[7];

			a += l & 0xffff;
			b += l >>> 16;
			c += h & 0xffff;
			d += h >>> 16;

			b += a >>> 16;
			c += b >>> 16;
			d += c >>> 16;

			hh[7] = ah7 = (c & 0xffff) | (d << 16);
			hl[7] = al7 = (a & 0xffff) | (b << 16);

			pos += 128;
			n -= 128;

			/*
			 * dbgt = ""; for (int dbg = 0; dbg < hh.length; dbg ++) dbgt += " "+hh[dbg];
			 * Log.d(TAG, "\ncrypto_hashblocks_hl hh -> "+dbgt);
			 *
			 * dbgt = ""; for (int dbg = 0; dbg < hl.length; dbg ++) dbgt += " "+hl[dbg];
			 * Log.d(TAG, "\ncrypto_hashblocks_hl hl -> "+dbgt);
			 */
		}

		return n;
	}

	// TBD 64bits of n
	/// int crypto_hash(byte [] out, byte [] m, long n)
	public static int crypto_hash(byte[] out, byte[] m, final int moff, int n) {
		int[] hh = new int[8], hl = new int[8];
		byte[] x = new byte[256];
		int i, b = n;
		long u;

		hh[0] = 0x6a09e667;
		hh[1] = 0xbb67ae85;
		hh[2] = 0x3c6ef372;
		hh[3] = 0xa54ff53a;
		hh[4] = 0x510e527f;
		hh[5] = 0x9b05688c;
		hh[6] = 0x1f83d9ab;
		hh[7] = 0x5be0cd19;

		hl[0] = 0xf3bcc908;
		hl[1] = 0x84caa73b;
		hl[2] = 0xfe94f82b;
		hl[3] = 0x5f1d36f1;
		hl[4] = 0xade682d1;
		hl[5] = 0x2b3e6c1f;
		hl[6] = 0xfb41bd6b;
		hl[7] = 0x137e2179;

		if (n >= 128) {
			crypto_hashblocks_hl(hh, hl, m, moff, n);
			n %= 128;
		}

		for (i = 0; i < n; i++)
			x[i] = m[b - n + i + moff];
		x[n] = (byte) 128;

		n = 256 - 128 * (n < 112 ? 1 : 0);
		x[n - 9] = 0;

		ts64(x, n - 8, b << 3/* (b / 0x20000000) | 0, b << 3 */);

		crypto_hashblocks_hl(hh, hl, x, 0, n);

		for (i = 0; i < 8; i++) {
			u = hh[i];
			u <<= 32;
			u |= hl[i] & 0xffffffffL;
			ts64(out, 8 * i, u);
		}

		return 0;
	}
	public static int crypto_hash(byte[] out, byte[] m) {
		return crypto_hash(out, m, 0, m != null ? m.length : 0);
	}

	// gf: long[16]
	/// private static void add(gf p[4],gf q[4])
	private static void add(long[] p[], long[] q[]) {
		long[] a = new long[16];
		long[] b = new long[16];
		long[] c = new long[16];
		long[] d = new long[16];
		long[] t = new long[16];
		long[] e = new long[16];
		long[] f = new long[16];
		long[] g = new long[16];
		long[] h = new long[16];

		long[] p0 = p[0];
		long[] p1 = p[1];
		long[] p2 = p[2];
		long[] p3 = p[3];

		long[] q0 = q[0];
		long[] q1 = q[1];
		long[] q2 = q[2];
		long[] q3 = q[3];

		Z(a, 0, p1, 0, p0, 0);
		Z(t, 0, q1, 0, q0, 0);
		M(a, 0, a, 0, t, 0);
		A(b, 0, p0, 0, p1, 0);
		A(t, 0, q0, 0, q1, 0);
		M(b, 0, b, 0, t, 0);
		M(c, 0, p3, 0, q3, 0);
		M(c, 0, c, 0, D2, 0);
		M(d, 0, p2, 0, q2, 0);

		A(d, 0, d, 0, d, 0);
		Z(e, 0, b, 0, a, 0);
		Z(f, 0, d, 0, c, 0);
		A(g, 0, d, 0, c, 0);
		A(h, 0, b, 0, a, 0);

		M(p0, 0, e, 0, f, 0);
		M(p1, 0, h, 0, g, 0);
		M(p2, 0, g, 0, f, 0);
		M(p3, 0, e, 0, h, 0);
	}

	private static void cswap(long[] p[], long[] q[], byte b) {
		int i;

		for (i = 0; i < 4; i++)
			sel25519(p[i], 0, q[i], 0, b);
	}

	private static void pack(byte[] r, long[] p[]) {
		long[] tx = new long[16];
		long[] ty = new long[16];
		long[] zi = new long[16];

		inv25519(zi, 0, p[2], 0);

		M(tx, 0, p[0], 0, zi, 0);
		M(ty, 0, p[1], 0, zi, 0);

		pack25519(r, ty, 0);

		r[31] ^= par25519(tx, 0) << 7;
	}

	private static void scalarmult(long[] p[], long[] q[], byte[] s, final int soff) {
		int i;

		set25519(p[0], gf0);
		set25519(p[1], gf1);
		set25519(p[2], gf1);
		set25519(p[3], gf0);

		for (i = 255; i >= 0; --i) {
			byte b = (byte) ((s[i / 8 + soff] >>> (i & 7)) & 1);

			cswap(p, q, b);
			add(q, p);
			add(p, p);
			cswap(p, q, b);
		}

		/// String dbgt = "";
		/// for (int dbg = 0; dbg < p.length; dbg ++) for (int dd = 0; dd <
		/// p[dbg].length; dd ++) dbgt += " "+p[dbg][dd];
		/// L/og.d(TAG, "scalarmult -> "+dbgt);
	}

	private static void scalarbase(long[] p[], byte[] s, final int soff) {
		long[][] q = new long[4][];

		q[0] = new long[16];
		q[1] = new long[16];
		q[2] = new long[16];
		q[3] = new long[16];

		set25519(q[0], X);
		set25519(q[1], Y);
		set25519(q[2], gf1);
		M(q[3], 0, X, 0, Y, 0);
		scalarmult(p, q, s, soff);
	}

	public static int crypto_sign_keypair(byte[] pk, byte[] sk, boolean seeded) {
		byte[] d = new byte[64];
		long[][] p = new long[4][];

		p[0] = new long[16];
		p[1] = new long[16];
		p[2] = new long[16];
		p[3] = new long[16];

		int i;

		if (!seeded)
			randombytes(sk, 32);
		crypto_hash(d, sk, 0, 32);
		d[0] &= 248;
		d[31] &= 127;
		d[31] |= 64;

		scalarbase(p, d, 0);
		pack(pk, p);

		for (i = 0; i < 32; i++)
			sk[i + 32] = pk[i];
		return 0;
	}

	private static final long L[] = {0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58, 0xd6, 0x9c, 0xf7, 0xa2, 0xde, 0xf9,
			0xde, 0x14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x10};

	private static void modL(byte[] r, final int roff, long x[]) {
		long carry;
		int i, j;

		for (i = 63; i >= 32; --i) {
			carry = 0;
			for (j = i - 32; j < i - 12; ++j) {
				x[j] += carry - 16 * x[i] * L[j - (i - 32)];
				carry = (x[j] + 128) >> 8;
				x[j] -= carry << 8;
			}
			x[j] += carry;
			x[i] = 0;
		}
		carry = 0;

		for (j = 0; j < 32; j++) {
			x[j] += carry - (x[31] >> 4) * L[j];
			carry = x[j] >> 8;
			x[j] &= 255;
		}

		for (j = 0; j < 32; j++)
			x[j] -= carry * L[j];

		for (i = 0; i < 32; i++) {
			x[i + 1] += x[i] >> 8;
			r[i + roff] = (byte) (x[i] & 255);
		}
	}

	private static void reduce(byte[] r) {
		long[] x = new long[64];
		int i;

		for (i = 0; i < 64; i++)
			x[i] = (long) (r[i] & 0xff);

		for (i = 0; i < 64; i++)
			r[i] = 0;

		modL(r, 0, x);
	}

	// TBD... 64bits of n
	/// int crypto_sign(byte [] sm, long * smlen, byte [] m, long n, byte [] sk)
	public static int crypto_sign(byte[] sm, long dummy /* *smlen not used */, byte[] m, final int moff,
			int/* long */ n, byte[] sk) {
		byte[] d = new byte[64], h = new byte[64], r = new byte[64];

		int i, j;
		long[] x = new long[64];

		long[][] p = new long[4][];
		p[0] = new long[16];
		p[1] = new long[16];
		p[2] = new long[16];
		p[3] = new long[16];

		crypto_hash(d, sk, 0, 32);
		d[0] &= 248;
		d[31] &= 127;
		d[31] |= 64;

		/// *smlen = n+64;

		for (i = 0; i < n; i++)
			sm[64 + i] = m[i + moff];

		for (i = 0; i < 32; i++)
			sm[32 + i] = d[32 + i];

		crypto_hash(r, sm, 32, n + 32);
		reduce(r);
		scalarbase(p, r, 0);
		pack(sm, p);

		for (i = 0; i < 32; i++)
			sm[i + 32] = sk[i + 32];
		crypto_hash(h, sm, 0, n + 64);
		reduce(h);

		for (i = 0; i < 64; i++)
			x[i] = 0;

		for (i = 0; i < 32; i++)
			x[i] = (long) (r[i] & 0xff);

		for (i = 0; i < 32; i++)
			for (j = 0; j < 32; j++)
				x[i + j] += (h[i] & 0xff) * (long) (d[j] & 0xff);

		modL(sm, 32, x);

		return 0;
	}

	private static int unpackneg(long[] r[], byte p[]) {
		long[] t = new long[16];
		long[] chk = new long[16];
		long[] num = new long[16];
		long[] den = new long[16];
		long[] den2 = new long[16];
		long[] den4 = new long[16];
		long[] den6 = new long[16];

		set25519(r[2], gf1);
		unpack25519(r[1], p);
		S(num, r[1]);
		M(den, num, D);
		Z(num, num, r[2]);
		A(den, r[2], den);

		S(den2, den);
		S(den4, den2);
		M(den6, den4, den2);
		M(t, den6, num);
		M(t, t, den);

		pow2523(t, t);
		M(t, t, num);
		M(t, t, den);
		M(t, t, den);
		M(r[0], t, den);

		S(chk, r[0]);
		M(chk, chk, den);
		if (neq25519(chk, num) != 0)
			M(r[0], r[0], I);

		S(chk, r[0]);
		M(chk, chk, den);
		if (neq25519(chk, num) != 0)
			return -1;

		if (par25519(r[0]) == ((p[31] & 0xFF) >>> 7))
			Z(r[0], gf0, r[0]);

		M(r[3], r[0], r[1]);

		return 0;
	}

	/// TBD 64bits of mlen
	/// int crypto_sign_open(byte []m,long *mlen,byte []sm,long n,byte []pk)
	public static int crypto_sign_open(byte[] m, long dummy /* *mlen not used */, byte[] sm, final int smoff,
			int/* long */ n, byte[] pk) {
		int i;
		byte[] t = new byte[32], h = new byte[64];

		long[][] p = new long[4][];
		p[0] = new long[16];
		p[1] = new long[16];
		p[2] = new long[16];
		p[3] = new long[16];

		long[][] q = new long[4][];
		q[0] = new long[16];
		q[1] = new long[16];
		q[2] = new long[16];
		q[3] = new long[16];

		/// *mlen = -1;

		if (n < 64)
			return -1;

		if (unpackneg(q, pk) != 0)
			return -1;

		for (i = 0; i < n; i++)
			m[i] = sm[i + smoff];

		for (i = 0; i < 32; i++)
			m[i + 32] = pk[i];

		crypto_hash(h, m, 0, n);

		reduce(h);
		scalarmult(p, q, h, 0);

		scalarbase(q, sm, 32 + smoff);
		add(p, q);
		pack(t, p);

		n -= 64;
		if (crypto_verify_32(sm, smoff, t, 0) != 0) {
			// optimizing it
			/// for (i = 0; i < n; i ++) m[i] = 0;
			return -1;
		}

		// TBD optimizing ...
		/// for (i = 0; i < n; i ++) m[i] = sm[i + 64 + smoff];
		/// *mlen = n;

		return 0;
	}

	/*
	 * @description Java SecureRandom generator
	 */
	private static final SecureRandom jrandom = new SecureRandom();

	public static byte[] randombytes(byte[] x) {
		jrandom.nextBytes(x);
		return x;
	}

	public static byte[] randombytes(int len) {
		return randombytes(new byte[len]);
	}

	public static byte[] randombytes(byte[] x, int len) {
		byte[] b = randombytes(len);
		System.arraycopy(b, 0, x, 0, len);
		return x;
	}

	/*
	 * public static byte[] randombytes(byte [] x, int len) { int ret = len % 8;
	 * long rnd;
	 *
	 * for (int i = 0; i < len-ret; i += 8) { rnd = jrandom.nextLong();
	 *
	 * x[i+0] = (byte) (rnd >>> 0); x[i+1] = (byte) (rnd >>> 8); x[i+2] = (byte)
	 * (rnd >>> 16); x[i+3] = (byte) (rnd >>> 24); x[i+4] = (byte) (rnd >>> 32);
	 * x[i+5] = (byte) (rnd >>> 40); x[i+6] = (byte) (rnd >>> 48); x[i+7] = (byte)
	 * (rnd >>> 56); }
	 *
	 * if (ret > 0) { rnd = jrandom.nextLong(); for (int i = len-ret; i < len; i ++)
	 * x[i] = (byte) (rnd >>> 8*i); } return x; }
	 */

	public static byte[] makeBoxNonce() {
		return randombytes(Box.nonceLength);
	}

	public static byte[] makeSecretBoxNonce() {
		return randombytes(SecretBox.nonceLength);
	}

	public static String hexEncodeToString(byte[] raw) {
		String HEXES = "0123456789ABCDEF";
		final StringBuilder hex = new StringBuilder(2 * raw.length);
		for (final byte b : raw) {
			hex.append(HEXES.charAt((b & 0xF0) >> 4)).append(HEXES.charAt((b & 0x0F)));
		}
		return hex.toString();
	}

	public static byte[] hexDecode(String s) {
		byte[] b = new byte[s.length() / 2];
		for (int i = 0; i < s.length(); i += 2) {
			b[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character.digit(s.charAt(i + 1), 16));
		}
		return b;
	}

	// public static boolean java.util.Arrays.equals(array1, array2);

}