Beispiel #1
0
// newManagedAddressWithoutPrivKey returns a new managed address based on the
// passed account, public key, and whether or not the public key should be
// compressed.
func newManagedAddressWithoutPrivKey(m *Manager, account uint32, pubKey *btcec.PublicKey, compressed bool) (*managedAddress, error) {
	// Create a pay-to-pubkey-hash address from the public key.
	var pubKeyHash []byte
	if compressed {
		pubKeyHash = coinutil.Hash160(pubKey.SerializeCompressed())
	} else {
		pubKeyHash = coinutil.Hash160(pubKey.SerializeUncompressed())
	}
	address, err := coinutil.NewAddressPubKeyHash(pubKeyHash, m.chainParams)
	if err != nil {
		return nil, err
	}

	return &managedAddress{
		manager:          m,
		address:          address,
		account:          account,
		imported:         false,
		internal:         false,
		compressed:       compressed,
		pubKey:           pubKey,
		privKeyEncrypted: nil,
		privKeyCT:        nil,
	}, nil
}
Beispiel #2
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// Exists returns true if an existing entry of 'sig' over 'sigHash' for public
// key 'pubKey' is found within the SigCache. Otherwise, false is returned.
//
// NOTE: This function is safe for concurrent access. Readers won't be blocked
// unless there exists a writer, adding an entry to the SigCache.
func (s *SigCache) Exists(sigHash wire.ShaHash, sig *btcec.Signature, pubKey *btcec.PublicKey) bool {
	info := sigInfo{sigHash, string(sig.Serialize()),
		string(pubKey.SerializeCompressed())}

	s.RLock()
	_, ok := s.validSigs[info]
	s.RUnlock()
	return ok
}
Beispiel #3
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// pubKeyBytes returns bytes for the serialized compressed public key associated
// with this extended key in an efficient manner including memoization as
// necessary.
//
// When the extended key is already a public key, the key is simply returned as
// is since it's already in the correct form.  However, when the extended key is
// a private key, the public key will be calculated and memoized so future
// accesses can simply return the cached result.
func (k *ExtendedKey) pubKeyBytes() []byte {
	// Just return the key if it's already an extended public key.
	if !k.isPrivate {
		return k.key
	}

	// This is a private extended key, so calculate and memoize the public
	// key if needed.
	if len(k.pubKey) == 0 {
		pkx, pky := btcec.S256().ScalarBaseMult(k.key)
		pubKey := btcec.PublicKey{Curve: btcec.S256(), X: pkx, Y: pky}
		k.pubKey = pubKey.SerializeCompressed()
	}

	return k.pubKey
}
Beispiel #4
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// Add adds an entry for a signature over 'sigHash' under public key 'pubKey'
// to the signature cache. In the event that the SigCache is 'full', an
// existing entry is randomly chosen to be evicted in order to make space for
// the new entry.
//
// NOTE: This function is safe for concurrent access. Writers will block
// simultaneous readers until function execution has concluded.
func (s *SigCache) Add(sigHash wire.ShaHash, sig *btcec.Signature, pubKey *btcec.PublicKey) {
	s.Lock()
	defer s.Unlock()

	if s.maxEntries <= 0 {
		return
	}

	// If adding this new entry will put us over the max number of allowed
	// entries, then evict an entry.
	if uint(len(s.validSigs)+1) > s.maxEntries {
		// Generate a cryptographically random hash.
		randHashBytes := make([]byte, wire.HashSize)
		_, err := rand.Read(randHashBytes)
		if err != nil {
			// Failure to read a random hash results in the proposed
			// entry not being added to the cache since we are
			// unable to evict any existing entries.
			return
		}

		// Try to find the first entry that is greater than the random
		// hash. Use the first entry (which is already pseudo random due
		// to Go's range statement over maps) as a fall back if none of
		// the hashes in the rejected transactions pool are larger than
		// the random hash.
		var foundEntry sigInfo
		for sigEntry := range s.validSigs {
			if foundEntry.sig == "" {
				foundEntry = sigEntry
			}
			if bytes.Compare(sigEntry.sigHash.Bytes(), randHashBytes) > 0 {
				foundEntry = sigEntry
				break
			}
		}
		delete(s.validSigs, foundEntry)
	}

	info := sigInfo{sigHash, string(sig.Serialize()),
		string(pubKey.SerializeCompressed())}
	s.validSigs[info] = struct{}{}
}
Beispiel #5
0
// Child returns a derived child extended key at the given index.  When this
// extended key is a private extended key (as determined by the IsPrivate
// function), a private extended key will be derived.  Otherwise, the derived
// extended key will be also be a public extended key.
//
// When the index is greater to or equal than the HardenedKeyStart constant, the
// derived extended key will be a hardened extended key.  It is only possible to
// derive a hardended extended key from a private extended key.  Consequently,
// this function will return ErrDeriveHardFromPublic if a hardened child
// extended key is requested from a public extended key.
//
// A hardened extended key is useful since, as previously mentioned, it requires
// a parent private extended key to derive.  In other words, normal child
// extended public keys can be derived from a parent public extended key (no
// knowledge of the parent private key) whereas hardened extended keys may not
// be.
//
// NOTE: There is an extremely small chance (< 1 in 2^127) the specific child
// index does not derive to a usable child.  The ErrInvalidChild error will be
// returned if this should occur, and the caller is expected to ignore the
// invalid child and simply increment to the next index.
func (k *ExtendedKey) Child(i uint32) (*ExtendedKey, error) {
	// There are four scenarios that could happen here:
	// 1) Private extended key -> Hardened child private extended key
	// 2) Private extended key -> Non-hardened child private extended key
	// 3) Public extended key -> Non-hardened child public extended key
	// 4) Public extended key -> Hardened child public extended key (INVALID!)

	// Case #4 is invalid, so error out early.
	// A hardened child extended key may not be created from a public
	// extended key.
	isChildHardened := i >= HardenedKeyStart
	if !k.isPrivate && isChildHardened {
		return nil, ErrDeriveHardFromPublic
	}

	// The data used to derive the child key depends on whether or not the
	// child is hardened per [BIP32].
	//
	// For hardened children:
	//   0x00 || ser256(parentKey) || ser32(i)
	//
	// For normal children:
	//   serP(parentPubKey) || ser32(i)
	keyLen := 33
	data := make([]byte, keyLen+4)
	if isChildHardened {
		// Case #1.
		// When the child is a hardened child, the key is known to be a
		// private key due to the above early return.  Pad it with a
		// leading zero as required by [BIP32] for deriving the child.
		copy(data[1:], k.key)
	} else {
		// Case #2 or #3.
		// This is either a public or private extended key, but in
		// either case, the data which is used to derive the child key
		// starts with the secp256k1 compressed public key bytes.
		copy(data, k.pubKeyBytes())
	}
	binary.BigEndian.PutUint32(data[keyLen:], i)

	// Take the HMAC-SHA512 of the current key's chain code and the derived
	// data:
	//   I = HMAC-SHA512(Key = chainCode, Data = data)
	hmac512 := hmac.New(sha512.New, k.chainCode)
	hmac512.Write(data)
	ilr := hmac512.Sum(nil)

	// Split "I" into two 32-byte sequences Il and Ir where:
	//   Il = intermediate key used to derive the child
	//   Ir = child chain code
	il := ilr[:len(ilr)/2]
	childChainCode := ilr[len(ilr)/2:]

	// Both derived public or private keys rely on treating the left 32-byte
	// sequence calculated above (Il) as a 256-bit integer that must be
	// within the valid range for a secp256k1 private key.  There is a small
	// chance (< 1 in 2^127) this condition will not hold, and in that case,
	// a child extended key can't be created for this index and the caller
	// should simply increment to the next index.
	ilNum := new(big.Int).SetBytes(il)
	if ilNum.Cmp(btcec.S256().N) >= 0 || ilNum.Sign() == 0 {
		return nil, ErrInvalidChild
	}

	// The algorithm used to derive the child key depends on whether or not
	// a private or public child is being derived.
	//
	// For private children:
	//   childKey = parse256(Il) + parentKey
	//
	// For public children:
	//   childKey = serP(point(parse256(Il)) + parentKey)
	var isPrivate bool
	var childKey []byte
	if k.isPrivate {
		// Case #1 or #2.
		// Add the parent private key to the intermediate private key to
		// derive the final child key.
		//
		// childKey = parse256(Il) + parenKey
		keyNum := new(big.Int).SetBytes(k.key)
		ilNum.Add(ilNum, keyNum)
		ilNum.Mod(ilNum, btcec.S256().N)
		childKey = ilNum.Bytes()
		isPrivate = true
	} else {
		// Case #3.
		// Calculate the corresponding intermediate public key for
		// intermediate private key.
		ilx, ily := btcec.S256().ScalarBaseMult(il)
		if ilx.Sign() == 0 || ily.Sign() == 0 {
			return nil, ErrInvalidChild
		}

		// Convert the serialized compressed parent public key into X
		// and Y coordinates so it can be added to the intermediate
		// public key.
		pubKey, err := btcec.ParsePubKey(k.key, btcec.S256())
		if err != nil {
			return nil, err
		}

		// Add the intermediate public key to the parent public key to
		// derive the final child key.
		//
		// childKey = serP(point(parse256(Il)) + parentKey)
		childX, childY := btcec.S256().Add(ilx, ily, pubKey.X, pubKey.Y)
		pk := btcec.PublicKey{Curve: btcec.S256(), X: childX, Y: childY}
		childKey = pk.SerializeCompressed()
	}

	// The fingerprint of the parent for the derived child is the first 4
	// bytes of the RIPEMD160(SHA256(parentPubKey)).
	parentFP := coinutil.Hash160(k.pubKeyBytes())[:4]
	return newExtendedKey(k.version, childKey, childChainCode, parentFP,
		k.depth+1, i, isPrivate), nil
}