Golang Hash.Size方法代码示例

// Tweak generates a new tweak from the mode, hash, salt length (in
// bytes), and any additional data. It provides additional information
// that will complicate an attacker's efforts, and allows a system to
// differentiate between different uses of the Catena function's output.
func Tweak(mode byte, H hash.Hash, saltLen int, ad []byte) ([]byte, error) {
	if mode != ModePassHash && mode != ModeKeyDerivation {
		return nil, ErrInvalidTweakMode
	}

	hashLen := H.Size()
	tweakLen := 5 + hashLen
	var t = make([]byte, 1, tweakLen)
	t[0] = mode

	var tmp uint16 = uint16(H.Size() * 8)
	high := byte(tmp >> 8)
	low := byte(tmp << 8 >> 8)
	t = append(t, high)
	t = append(t, low)

	tmp = uint16(saltLen * 8)
	high = byte(tmp >> 8)
	low = byte(tmp << 8 >> 8)
	t = append(t, high)
	t = append(t, low)

	H.Reset()
	H.Write(ad)
	t = append(t, H.Sum(nil)...)
	H.Reset()
	return t, nil
}

func Encode(k int, h hash.Hash, value []byte, output int) (enc []byte, s [][]byte) {
	s0 := make([]byte, h.Size())

	n := len(value)
	blockcount := n / k

	s = make([][]byte, blockcount)

	for i := 0; i < blockcount; i++ {
		h.Reset()
		if i == 0 {
			h.Write(s0)
		} else {
			h.Write(s[i-1])
		}

		h.Write(value[i*k : (i+1)*k])
		s[i] = h.Sum(make([]byte, 0, h.Size()))
	}

	rng := make([](*RNG), len(s))
	for i := 0; i < len(s); i++ {
		rng[i] = NewRNG(h, s[i])
	}

	enc = make([]byte, output)

	for i := 0; i < output; i++ {
		enc[i] = rng[i%blockcount].Next()
	}

	return
}

// decode uses the given block cipher (in CTR mode) to decrypt the
// data, and validate the hash.  If hash validation fails, an error is
// returned.
func decode(block cipher.Block, hmac hash.Hash, ciphertext []byte) ([]byte, error) {
	if len(ciphertext) < 2*block.BlockSize()+hmac.Size() {
		return nil, LenError
	}

	receivedHmac := ciphertext[len(ciphertext)-hmac.Size():]
	ciphertext = ciphertext[:len(ciphertext)-hmac.Size()]

	hmac.Write(ciphertext)
	if subtle.ConstantTimeCompare(hmac.Sum(nil), receivedHmac) != 1 {
		return nil, HashError
	}

	// split the iv and session bytes
	iv := ciphertext[len(ciphertext)-block.BlockSize():]
	session := ciphertext[:len(ciphertext)-block.BlockSize()]

	stream := cipher.NewCTR(block, iv)
	stream.XORKeyStream(session, session)

	// skip past the iv
	session = session[block.BlockSize():]

	return session, nil
}

// DeriveConcatKDF implements NIST SP 800-56A Concatenation Key Derivation Function. Derives
// key material of keydatalen bits size given Z (sharedSecret), OtherInfo (AlgorithmID |
// PartyUInfo | PartyVInfo | SuppPubInfo | SuppPrivInfo) and hash function
func DeriveConcatKDF(keydatalen int, sharedSecret, algId, partyUInfo, partyVInfo, suppPubInfo, suppPrivInfo []byte, h hash.Hash) []byte {

	otherInfo := arrays.Concat(algId, partyUInfo, partyVInfo, suppPubInfo, suppPrivInfo)

	keyLenBytes := keydatalen >> 3

	reps := int(math.Ceil(float64(keyLenBytes) / float64(h.Size())))

	if reps > MaxInt {
		panic("kdf.DeriveConcatKDF: too much iterations (more than 2^32-1).")
	}

	dk := make([]byte, 0, keyLenBytes)

	for counter := 1; counter <= reps; counter++ {
		h.Reset()

		counterBytes := arrays.UInt32ToBytes(uint32(counter))

		h.Write(counterBytes)
		h.Write(sharedSecret)
		h.Write(otherInfo)

		dk = h.Sum(dk)
	}

	return dk[:keyLenBytes]
}

// EncryptOAEP encrypts the given message with RSA-OAEP.
// The message must be no longer than the length of the public modulus less
// twice the hash length plus 2.
func EncryptOAEP(hash hash.Hash, rand io.Reader, pub *PublicKey, msg []byte, label []byte) (out []byte, err os.Error) {
	hash.Reset()
	k := (pub.N.Len() + 7) / 8
	if len(msg) > k-2*hash.Size()-2 {
		err = MessageTooLongError{}
		return
	}

	hash.Write(label)
	lHash := hash.Sum()
	hash.Reset()

	em := make([]byte, k)
	seed := em[1 : 1+hash.Size()]
	db := em[1+hash.Size():]

	copy(db[0:hash.Size()], lHash)
	db[len(db)-len(msg)-1] = 1
	copy(db[len(db)-len(msg):], msg)

	_, err = io.ReadFull(rand, seed)
	if err != nil {
		return
	}

	mgf1XOR(db, hash, seed)
	mgf1XOR(seed, hash, db)

	m := new(big.Int)
	m.SetBytes(em)
	c := encrypt(new(big.Int), pub, m)
	out = c.Bytes()
	return
}

func (s *descbc) Decrypt(salt []byte, algo, usage int, data []byte) ([]byte, error) {
	var h hash.Hash

	switch algo {
	case cryptDesCbcMd5:
		h = md5.New()
	case cryptDesCbcMd4:
		h = md4.New()
	default:
		return nil, ErrProtocol
	}

	if (len(data) & 7) != 0 {
		return nil, ErrProtocol
	}

	iv := [8]byte{}
	b, _ := des.NewCipher(s.key)
	c := cipher.NewCBCDecrypter(b, iv[:])
	c.CryptBlocks(data, data)

	chk := make([]byte, h.Size())
	h.Write(data[:8])
	h.Write(chk) // Just need h.Size() zero bytes instead of the checksum
	h.Write(data[8+len(chk):])
	h.Sum(chk[:0])

	if subtle.ConstantTimeCompare(chk, data[8:8+len(chk)]) != 1 {
		return nil, ErrProtocol
	}

	return data[8+len(chk):], nil
}

func NewHashAppendReader(r io.Reader, h hash.Hash) *HashAppendReader {
	return &HashAppendReader{
		h:   h,
		r:   io.TeeReader(r, h),
		sum: make([]byte, 0, h.Size()),
	}
}

// jssdk 支付签名, signType 只支持 "MD5", "SHA1", 传入其他的值会 panic.
func JsapiSign(appId, timeStamp, nonceStr, packageStr, signType string, apiKey string) string {
	var h hash.Hash
	switch signType {
	case "MD5":
		h = md5.New()
	case "SHA1":
		h = sha1.New()
	default:
		panic("unsupported signType")
	}
	bufw := bufio.NewWriterSize(h, 128)

	// appId
	// nonceStr
	// package
	// signType
	// timeStamp
	bufw.WriteString("appId=")
	bufw.WriteString(appId)
	bufw.WriteString("&nonceStr=")
	bufw.WriteString(nonceStr)
	bufw.WriteString("&package=")
	bufw.WriteString(packageStr)
	bufw.WriteString("&signType=")
	bufw.WriteString(signType)
	bufw.WriteString("&timeStamp=")
	bufw.WriteString(timeStamp)
	bufw.WriteString("&key=")
	bufw.WriteString(apiKey)

	bufw.Flush()
	signature := make([]byte, hex.EncodedLen(h.Size()))
	hex.Encode(signature, h.Sum(nil))
	return string(bytes.ToUpper(signature))
}

func NewRNG(h hash.Hash, seed []byte) (r *RNG) {
	r = new(RNG)
	r.i = 3610617884
	r.h = h
	r.buffer = make([]byte, 0, h.Size())
	r.seed = seed
	return
}

func GenSessionId() string {
	var h hash.Hash = sessHash()
	h.Write(GenRandomBytes(sessEnthropy))
	h.Write([]byte(strconv.FormatInt(time.Now().Unix(), 10)))
	id := make([]byte, 0, h.Size())
	id = h.Sum(id)
	return base64.StdEncoding.EncodeToString(id)
}

func NewHashAppendWriter(w io.Writer, h hash.Hash) *HashAppendWriter {
	return &HashAppendWriter{
		h:      h,
		w:      io.MultiWriter(w, h),
		origWr: w,
		sum:    make([]byte, 0, h.Size()),
	}
}

// GoId creates a UUID object based on timestamps and a hash.
// It will truncate any bytes past the length of the initial hash.
// This creates a UUID based on a Namespace, UniqueName and an existing
// hash.
func GoId(pNs UUID, pName UniqueName, pHash hash.Hash) UUID {
	o := new(UUIDStruct)
	o.size = pHash.Size()
	Digest(o, pNs, pName, pHash)
	now := currentUUIDTimestamp()
	sequence := uint16(seed.Int()) & 0x3FFF
	return formatGoId(o, now, 15, ReservedFuture, sequence)
}

// this is the function which calculates the HTOP code
func calculateToken(counter []byte, digits int, h hash.Hash) string {

	h.Write(counter)
	hashResult := h.Sum(nil)
	result := truncateHash(hashResult, h.Size())

	mod := int32(result % int64(math.Pow10(digits)))

	fmtStr := fmt.Sprintf("%%0%dd", digits)

	return fmt.Sprintf(fmtStr, mod)
}

func hashWithPrefix(out []byte, prefix byte, in []byte, h hash.Hash) {
	h.Reset()
	var p [1]byte
	p[0] = prefix
	h.Write(p[:])
	h.Write(in)
	if len(out) == h.Size() {
		h.Sum(out[:0])
	} else {
		digest := h.Sum(nil)
		copy(out, digest)
	}
}

func testWrite(msg string, t *testing.T, h hash.Hash, c *Config) {
	var msg1 []byte
	msg0 := make([]byte, 64)
	for i := range msg0 {
		h.Write(msg0[:i])
		msg1 = append(msg1, msg0[:i]...)
	}
	tag0 := h.Sum(nil)
	tag1 := Sum(msg1, h.Size(), c)

	if !bytes.Equal(tag0, tag1) {
		t.Fatalf("%s\nSum differ from Sum\n Sum: %s \n skein.Sum: %s", msg, hex.EncodeToString(tag0), hex.EncodeToString(tag1))
	}
}