Esempio n. 1
0
// Reset generates a new distribution with the same min/max based on a new
// seed.
func (w *WeightedDist) Reset(seed *drbg.Seed) {
	// Initialize the deterministic random number generator.
	drbg, _ := drbg.NewHashDrbg(seed)
	rng := rand.New(drbg)

	w.Lock()
	defer w.Unlock()

	w.genValues(rng)
	if w.biased {
		w.genBiasedWeights(rng)
	} else {
		w.genUniformWeights(rng)
	}
	w.genTables()
}
Esempio n. 2
0
// NewDecoder creates a new Decoder instance.  It must be supplied a slice
// containing exactly KeyLength bytes of keying material.
func NewDecoder(key []byte) *Decoder {
	if len(key) != KeyLength {
		panic(fmt.Sprintf("BUG: Invalid decoder key length: %d", len(key)))
	}

	decoder := new(Decoder)
	copy(decoder.key[:], key[0:keyLength])
	decoder.nonce.init(key[keyLength : keyLength+noncePrefixLength])
	seed, err := drbg.SeedFromBytes(key[keyLength+noncePrefixLength:])
	if err != nil {
		panic(fmt.Sprintf("BUG: Failed to initialize DRBG: %s", err))
	}
	decoder.drbg, _ = drbg.NewHashDrbg(seed)

	return decoder
}
Esempio n. 3
0
// ServerFactory returns a new obfs4ServerFactory instance.
func (t *Transport) ServerFactory(stateDir string, args *pt.Args) (base.ServerFactory, error) {
	st, err := serverStateFromArgs(stateDir, args)
	if err != nil {
		return nil, err
	}

	var iatSeed *drbg.Seed
	if st.iatMode != iatNone {
		iatSeedSrc := sha256.Sum256(st.drbgSeed.Bytes()[:])
		var err error
		iatSeed, err = drbg.SeedFromBytes(iatSeedSrc[:])
		if err != nil {
			return nil, err
		}
	}

	// Store the arguments that should appear in our descriptor for the clients.
	ptArgs := pt.Args{}
	ptArgs.Add(certArg, st.cert.String())
	ptArgs.Add(iatArg, strconv.Itoa(st.iatMode))

	// Initialize the replay filter.
	filter, err := replayfilter.New(replayTTL)
	if err != nil {
		return nil, err
	}

	// Initialize the close thresholds for failed connections.
	drbg, err := drbg.NewHashDrbg(st.drbgSeed)
	if err != nil {
		return nil, err
	}
	rng := rand.New(drbg)

	sf := &obfs4ServerFactory{t, &ptArgs, st.nodeID, st.identityKey, st.drbgSeed, iatSeed, st.iatMode, filter, rng.Intn(maxCloseDelayBytes), rng.Intn(maxCloseDelay)}
	return sf, nil
}