Golang Int.Bytes方法代码示例

// bigIntToNetIPv6 is a helper function that correctly returns a net.IP with the
// correctly padded values.
func bigIntToNetIPv6(bi *big.Int) *net.IP {
	x := make(net.IP, IPv6len)
	ipv6Bytes := bi.Bytes()

	// It's possibe for ipv6Bytes to be less than IPv6len bytes in size.  If
	// they are different sizes we to pad the size of response.
	if len(ipv6Bytes) < IPv6len {
		buf := new(bytes.Buffer)
		buf.Grow(IPv6len)

		for i := len(ipv6Bytes); i < IPv6len; i++ {
			if err := binary.Write(buf, binary.BigEndian, byte(0)); err != nil {
				panic(fmt.Sprintf("Unable to pad byte %d of input %v: %v", i, bi, err))
			}
		}

		for _, b := range ipv6Bytes {
			if err := binary.Write(buf, binary.BigEndian, b); err != nil {
				panic(fmt.Sprintf("Unable to preserve endianness of input %v: %v", bi, err))
			}
		}

		ipv6Bytes = buf.Bytes()
	}
	i := copy(x, ipv6Bytes)
	if i != IPv6len {
		panic("IPv6 wrong size")
	}
	return &x
}

// privateEncrypt implements OpenSSL's RSA_private_encrypt function
func privateEncrypt(key *rsa.PrivateKey, data []byte) (enc []byte, err error) {
	k := (key.N.BitLen() + 7) / 8
	tLen := len(data)

	// rfc2313, section 8:
	// The length of the data D shall not be more than k-11 octets
	if tLen > k-11 {
		err = errors.New("Data too long")
		return
	}
	em := make([]byte, k)
	em[1] = 1
	for i := 2; i < k-tLen-1; i++ {
		em[i] = 0xff
	}
	copy(em[k-tLen:k], data)
	c := new(big.Int).SetBytes(em)
	if c.Cmp(key.N) > 0 {
		err = nil
		return
	}
	var m *big.Int
	var ir *big.Int
	if key.Precomputed.Dp == nil {
		m = new(big.Int).Exp(c, key.D, key.N)
	} else {
		// We have the precalculated values needed for the CRT.
		m = new(big.Int).Exp(c, key.Precomputed.Dp, key.Primes[0])
		m2 := new(big.Int).Exp(c, key.Precomputed.Dq, key.Primes[1])
		m.Sub(m, m2)
		if m.Sign() < 0 {
			m.Add(m, key.Primes[0])
		}
		m.Mul(m, key.Precomputed.Qinv)
		m.Mod(m, key.Primes[0])
		m.Mul(m, key.Primes[1])
		m.Add(m, m2)

		for i, values := range key.Precomputed.CRTValues {
			prime := key.Primes[2+i]
			m2.Exp(c, values.Exp, prime)
			m2.Sub(m2, m)
			m2.Mul(m2, values.Coeff)
			m2.Mod(m2, prime)
			if m2.Sign() < 0 {
				m2.Add(m2, prime)
			}
			m2.Mul(m2, values.R)
			m.Add(m, m2)
		}
	}

	if ir != nil {
		// Unblind.
		m.Mul(m, ir)
		m.Mod(m, key.N)
	}
	enc = m.Bytes()
	return
}

// Appends to data the first (len(data) / 32)bits of the result of sha256(data)
// Currently only supports data up to 32 bytes
func addChecksum(data []byte) []byte {
	// Get first byte of sha256
	hasher := sha256.New()
	hasher.Write(data)
	hash := hasher.Sum(nil)
	firstChecksumByte := hash[0]

	// len() is in bytes so we divide by 4
	checksumBitLength := uint(len(data) / 4)

	// For each bit of check sum we want we shift the data one the left
	// and then set the (new) right most bit equal to checksum bit at that index
	// staring from the left
	dataBigInt := new(big.Int).SetBytes(data)
	for i := uint(0); i < checksumBitLength; i++ {
		// Bitshift 1 left
		dataBigInt.Mul(dataBigInt, BigTwo)

		// Set rightmost bit if leftmost checksum bit is set
		if uint8(firstChecksumByte&(1<<(7-i))) > 0 {
			dataBigInt.Or(dataBigInt, BigOne)
		}
	}

	return dataBigInt.Bytes()
}

func (ka *dheKeyAgreement) generateServerKeyExchange(config *Config, cert *Certificate, clientHello *clientHelloMsg, hello *serverHelloMsg) (*serverKeyExchangeMsg, error) {
	var q *big.Int
	if p := config.Bugs.DHGroupPrime; p != nil {
		ka.p = p
		ka.g = big.NewInt(2)
		q = p
	} else {
		// 2048-bit MODP Group with 256-bit Prime Order Subgroup (RFC
		// 5114, Section 2.3)
		ka.p, _ = new(big.Int).SetString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
		ka.g, _ = new(big.Int).SetString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
		q, _ = new(big.Int).SetString("8CF83642A709A097B447997640129DA299B1A47D1EB3750BA308B0FE64F5FBD3", 16)
	}

	var err error
	ka.xOurs, err = rand.Int(config.rand(), q)
	if err != nil {
		return nil, err
	}
	yOurs := new(big.Int).Exp(ka.g, ka.xOurs, ka.p)

	// http://tools.ietf.org/html/rfc5246#section-7.4.3
	pBytes := ka.p.Bytes()
	gBytes := ka.g.Bytes()
	yBytes := yOurs.Bytes()
	serverDHParams := make([]byte, 0, 2+len(pBytes)+2+len(gBytes)+2+len(yBytes))
	serverDHParams = append(serverDHParams, byte(len(pBytes)>>8), byte(len(pBytes)))
	serverDHParams = append(serverDHParams, pBytes...)
	serverDHParams = append(serverDHParams, byte(len(gBytes)>>8), byte(len(gBytes)))
	serverDHParams = append(serverDHParams, gBytes...)
	serverDHParams = append(serverDHParams, byte(len(yBytes)>>8), byte(len(yBytes)))
	serverDHParams = append(serverDHParams, yBytes...)

	return ka.auth.signParameters(config, cert, clientHello, hello, serverDHParams)
}

// Sign signs an arbitrary length hash (which should be the result of hashing a
// larger message) using the private key, priv. It returns the signature as a
// pair of integers. The security of the private key depends on the entropy of
// rand.
func Sign(rand io.Reader, priv *PrivateKey, hash []byte) (r, s *big.Int, err error) {
	// See [NSA] 3.4.1
	c := priv.PublicKey.Curve
	N := c.Params().N

	var k, kInv *big.Int
	for {
		for {
			k, err = randFieldElement(c, rand)
			if err != nil {
				r = nil
				return
			}

			kInv = new(big.Int).ModInverse(k, N)
			r, _ = priv.Curve.ScalarBaseMult(k.Bytes())
			r.Mod(r, N)
			if r.Sign() != 0 {
				break
			}
		}

		e := hashToInt(hash, c)
		s = new(big.Int).Mul(priv.D, r)
		s.Add(s, e)
		s.Mul(s, kInv)
		s.Mod(s, N)
		if s.Sign() != 0 {
			break
		}
	}

	return
}

func makeBigInt(n *big.Int) (encoder, error) {
	if n == nil {
		return nil, StructuralError{"empty integer"}
	}

	if n.Sign() < 0 {
		// A negative number has to be converted to two's-complement
		// form. So we'll invert and subtract 1. If the
		// most-significant-bit isn't set then we'll need to pad the
		// beginning with 0xff in order to keep the number negative.
		nMinus1 := new(big.Int).Neg(n)
		nMinus1.Sub(nMinus1, bigOne)
		bytes := nMinus1.Bytes()
		for i := range bytes {
			bytes[i] ^= 0xff
		}
		if len(bytes) == 0 || bytes[0]&0x80 == 0 {
			return multiEncoder([]encoder{byteFFEncoder, bytesEncoder(bytes)}), nil
		}
		return bytesEncoder(bytes), nil
	} else if n.Sign() == 0 {
		// Zero is written as a single 0 zero rather than no bytes.
		return byte00Encoder, nil
	} else {
		bytes := n.Bytes()
		if len(bytes) > 0 && bytes[0]&0x80 != 0 {
			// We'll have to pad this with 0x00 in order to stop it
			// looking like a negative number.
			return multiEncoder([]encoder{byte00Encoder, bytesEncoder(bytes)}), nil
		}
		return bytesEncoder(bytes), nil
	}
}

/*公钥解密*/
func pubKeyDecrypt(pub *rsa.PublicKey, data []byte) ([]byte, error) {
	k := (pub.N.BitLen() + 7) / 8
	if k != len(data) {
		return nil, ErrDataLen
	}
	m := new(big.Int).SetBytes(data)
	if m.Cmp(pub.N) > 0 {
		return nil, ErrDataToLarge
	}
	m.Exp(m, big.NewInt(int64(pub.E)), pub.N)
	d := leftPad(m.Bytes(), k)
	if d[0] != 0 {
		return nil, ErrDataBroken
	}
	if d[1] != 0 && d[1] != 1 {
		return nil, ErrKeyPairDismatch
	}
	var i = 2
	for ; i < len(d); i++ {
		if d[i] == 0 {
			break
		}
	}
	i++
	if i == len(d) {
		return nil, nil
	}
	return d[i:], nil
}

func TestP256BaseMult(t *testing.T) {
	p256 := P256()
	p256Generic := p256.Params()

	scalars := make([]*big.Int, 0, len(p224BaseMultTests)+1)
	for _, e := range p224BaseMultTests {
		k, _ := new(big.Int).SetString(e.k, 10)
		scalars = append(scalars, k)
	}
	k := new(big.Int).SetInt64(1)
	k.Lsh(k, 500)
	scalars = append(scalars, k)

	for i, k := range scalars {
		x, y := p256.ScalarBaseMult(k.Bytes())
		x2, y2 := p256Generic.ScalarBaseMult(k.Bytes())
		if x.Cmp(x2) != 0 || y.Cmp(y2) != 0 {
			t.Errorf("#%d: got (%x, %x), want (%x, %x)", i, x, y, x2, y2)
		}

		if testing.Short() && i > 5 {
			break
		}
	}
}

// Compile instruction
//
// Attempts to compile and parse the given instruction in "s"
// and returns the byte sequence
func CompileInstr(s interface{}) ([]byte, error) {
	switch s.(type) {
	case string:
		str := s.(string)
		isOp := IsOpCode(str)
		if isOp {
			return []byte{OpCodes[str]}, nil
		}

		// Check for pre formatted byte array
		// Jumps are preformatted
		if []byte(str)[0] == 0 {
			return []byte(str), nil
		}

		num := new(big.Int)
		_, success := num.SetString(str, 0)
		// Assume regular bytes during compilation
		if !success {
			num.SetBytes([]byte(str))
		}

		return num.Bytes(), nil
	case int:
		//num := bigToBytes(big.NewInt(int64(s.(int))), 256)
		return big.NewInt(int64(s.(int))).Bytes(), nil
	case []byte:
		return new(big.Int).SetBytes(s.([]byte)).Bytes(), nil
	}

	return nil, nil
}

func EncodePublicKey(x, y *big.Int, compressed bool) ([]byte, error) {
	var pubkey []byte
	if compressed {
		pubkey = make([]byte, 33)
		pubkey[0] = 2 + byte(y.Bit(0))
	} else {
		pubkey = make([]byte, 65)
		pubkey[0] = 4
	}

	// Right-align x coordinate
	bytes := x.Bytes()
	if len(bytes) > 32 {
		return nil, fmt.Errorf("Value of x has > 32 bytes")
	}
	copy(pubkey[1+(32-len(bytes)):33], bytes)

	if !compressed {
		// Right-align y coordinate
		bytes = y.Bytes()
		if len(bytes) > 32 {
			return nil, fmt.Errorf("Value of y has > 32 bytes")
		}
		copy(pubkey[33+(32-len(bytes)):65], bytes)
	}

	return pubkey, nil
}

// Converts a number to a binary byte slice
// i.e. 4 => [0,0,0,4]
// 256 => [0,0,1,0]
// or in the case of 64
// 4 = > [0,0,0,0,0,0,0,4]
func makeBinary(value interface{}) []byte {
	var z []byte
	var val uint64

	amount := 4

	if v, ok := value.(uint64); ok {
		amount = 8
		val = v
	} else if v, ok := value.(uint32); ok {
		val = uint64(v)
	} else {
		log.Panic("makeBinary requires a value that's either a uint32 or an uint64, got:", value)
	}

	str := strconv.FormatUint(val, 10)

	number := new(big.Int)
	number.SetString(str, 10)

	template := make([]byte, amount)

	x := number.Bytes()
	z = append(template[:(amount-len(x))], x...)

	return z
}

func wipeBigInt(k *big.Int) {
	if k == nil {
		return
	}

	k.SetBytes(zeroes(len(k.Bytes())))
}

// powerOffset computes the offset by (n + 2^exp) % (2^mod)
func powerOffset(id []byte, exp int, mod int) []byte {
	// Copy the existing slice
	off := make([]byte, len(id))
	copy(off, id)

	// Convert the ID to a bigint
	idInt := big.Int{}
	idInt.SetBytes(id)

	// Get the offset
	two := big.NewInt(2)
	offset := big.Int{}
	offset.Exp(two, big.NewInt(int64(exp)), nil)

	// Sum
	sum := big.Int{}
	sum.Add(&idInt, &offset)

	// Get the ceiling
	ceil := big.Int{}
	ceil.Exp(two, big.NewInt(int64(mod)), nil)

	// Apply the mod
	idInt.Mod(&sum, &ceil)

	// Add together
	return idInt.Bytes()
}

func Unblind(key *rsa.PublicKey, blindedSig, unblinder []byte) []byte {
	m := new(big.Int).SetBytes(blindedSig)
	unblinderBig := new(big.Int).SetBytes(unblinder)
	m.Mul(m, unblinderBig)
	m.Mod(m, key.N)
	return m.Bytes()
}

func SendToConn(data []byte, conn *net.TCPConn, path *big.Int) {
	// making variable for combining send data
	var (
		err           tree_lib.TreeError
		path_len_data = make([]byte, 4)
		msg_len_data  = make([]byte, 4)
		path_data     = path.Bytes()
		path_len      = uint32(len(path_data))
		buf           = bytes.Buffer{}
	)

	err.From = tree_lib.FROM_SEND_TO_CONN

	binary.LittleEndian.PutUint32(path_len_data, path_len)
	binary.LittleEndian.PutUint32(msg_len_data, path_len+uint32(len(data))+uint32(4))

	buf.Write(msg_len_data)
	buf.Write(path_len_data)
	buf.Write(path_data)
	buf.Write(data)

	if conn != nil {
		_, err.Err = conn.Write(buf.Bytes())
		if !err.IsNull() {
			tree_log.Error(err.From, fmt.Sprintf("Error sending data to path [%s]", path.String()), err.Error())
		}
	}

	buf.Reset()
}