Merge pull request #4 from kaspanet/2020-03-setBytes

Add constants and implement DeserializeXXXFromSlice for all serialized objects

multiset.go

@@ -7,6 +7,9 @@ import (
 	"github.com/pkg/errors"
 )
 
+// SerializedMultiSetSize defines the length in bytes of SerializedMultiSet
+const SerializedMultiSetSize = 64
+
 // MultiSet is a type used to create an Elliptic Curve Multiset Hash
 // which is a rolling(homomorphic) hash that you can add and remove elements from
 // and receiving the same resulting hash as-if you never hashed that element.
@@ -17,7 +20,7 @@ type MultiSet struct {
 }
 
 // SerializedMultiSet is a is a byte array representing the storage representation of a MultiSet
-type SerializedMultiSet [64]byte
+type SerializedMultiSet [SerializedMultiSetSize]byte
 
 // String returns the SerializedMultiSet as the hexadecimal string
 func (serialized *SerializedMultiSet) String() string {
@@ -114,3 +117,15 @@ func DeserializeMultiSet(serialized *SerializedMultiSet) (multiset *MultiSet, er
 	}
 	return
 }
+
+// DeserializeMultiSetFromSlice returns a MultiSet type from a from a a serialized multiset slice.
+// will verify that it's SerializedMultiSetSize bytes long and a valid multiset.
+func DeserializeMultiSetFromSlice(newMultiSet []byte) (multiset *MultiSet, err error) {
+	if len(newMultiSet) != SerializedMultiSetSize {
+		return nil, errors.Errorf("invalid multiset length got %d, expected %d", len(newMultiSet),
+			SerializedMultiSetSize)
+	}
+	serializedMultiSet := &SerializedMultiSet{}
+	copy(serializedMultiSet[:], newMultiSet)
+	return DeserializeMultiSet(serializedMultiSet)
+}

oldschnorr.go

@@ -8,6 +8,17 @@ import (
 	"github.com/pkg/errors"
 )
 
+const (
+	// SerializedSchnorrPublicKeyCompressedSize defines the length in bytes of SerializedSchnorrPublicKeyCompressed
+	SerializedSchnorrPublicKeyCompressedSize = 33
+
+	// SerializedSchnorrPublicKeyUncompressedSize defines the length in bytes of SerializedSchnorrPublicKeyUncompressed
+	SerializedSchnorrPublicKeyUncompressedSize = 65
+
+	// SerializedSchnorrSignatureSize defines the length in bytes of SerializedSchnorrSignature
+	SerializedSchnorrSignatureSize = 64
+)
+
 // SchnorrPublicKey is a PublicKey type used to sign and verify Schnorr signatures.
 // The struct itself is an opaque data type that should only be created via the supplied methods.
 type SchnorrPublicKey struct {
@@ -17,14 +28,14 @@ type SchnorrPublicKey struct {
 // SchnorrSignature is a type representing a Schnorr Signature.
 // The struct itself is an opaque data type that should only be created via the supplied methods.
 type SchnorrSignature struct {
-	signature [64]byte
+	signature [SerializedSchnorrSignatureSize]byte
 }
 
 // SerializedSchnorrPublicKey is a is a byte array representing the storage representation of a compressed or uncompressed SchnorrPublicKey
 type SerializedSchnorrPublicKey []byte
 
 // SerializedSchnorrSignature is a is a byte array representing the storage representation of a SchnorrSignature
-type SerializedSchnorrSignature [64]byte
+type SerializedSchnorrSignature [SerializedSchnorrSignatureSize]byte
 
 // IsEqual returns true if target is the same as key.
 func (key *SchnorrPublicKey) IsEqual(target *SchnorrPublicKey) bool {
@@ -83,6 +94,18 @@ func DeserializeSchnorrSignature(serializedSignature *SerializedSchnorrSignature
 	return &SchnorrSignature{signature: *serializedSignature}
 }
 
+// DeserializeSchnorrSignatureFromSlice returns a SchnorrSignature type from a serialized signature slice.
+// will verify that it's SerializedSchnorrSignatureSize bytes long
+func DeserializeSchnorrSignatureFromSlice(data []byte) (signature *SchnorrSignature, err error) {
+	if len(data) != SerializedSchnorrSignatureSize {
+		return nil, errors.Errorf("invalid schnorr signature length got %d, expected %d", len(data),
+			SerializedSchnorrSignatureSize)
+	}
+	signature = &SchnorrSignature{}
+	copy(signature.signature[:], data)
+	return
+}
+
 // String returns the SchnorrPublicKey as the hexadecimal string
 func (key *SchnorrPublicKey) String() string {
 	serialized, err := key.SerializeCompressed()
@@ -185,16 +208,16 @@ func (key *SchnorrPublicKey) serializeInternal(flag C.uint) (SerializedSchnorrPu
 	ret := C.secp256k1_ec_pubkey_serialize(C.secp256k1_context_no_precomp, cPtr, &cLen, &key.pubkey, flag)
 	if ret != 1 {
 		panic("failed serializing a pubkey. Should never happen (upstream promise to return 1)")
-	} else if cLen != 33 && cLen != 65 {
+	} else if cLen != SerializedSchnorrPublicKeyCompressedSize && cLen != SerializedSchnorrPublicKeyUncompressedSize {
 		panic("Returned length doesn't match compressed length(33) nor uncompressed length(65), should never happen")
 	}
 	return data[:cLen], nil
 }
 
 func supportedKey(key []byte) bool {
-	if len(key) == 33 && (key[0] == 0x02 || key[0] == 0x03) {
+	if len(key) == SerializedSchnorrPublicKeyCompressedSize && (key[0] == 0x02 || key[0] == 0x03) {
 		return true
-	} else if len(key) == 65 && key[0] == 0x04 {
+	} else if len(key) == SerializedSchnorrPublicKeyUncompressedSize && key[0] == 0x04 {
 		return true
 	} else {
 		return false

secp256k1.go

@@ -44,8 +44,13 @@ func init() {
 	}
 }
 
-// HashSize of array used to store hashes. See Hash.
-const HashSize = 32
+const (
+	// HashSize of array used to store hashes. See Hash.
+	HashSize = 32
+
+	// SerializedPrivateKeySize defines the length in bytes of SerializedPrivateKey
+	SerializedPrivateKeySize = 32
+)
 
 // Hash is a type encapsulating the result of hashing some unknown sized data.
 // it typically represents Sha256 / Double Sha256.
@@ -81,11 +86,11 @@ func (hash *Hash) String() string {
 // PrivateKey is a type representing a Secp256k1 private key.
 // This private key can be used to create Schnorr/ECDSA signatures
 type PrivateKey struct {
-	privateKey [32]byte
+	privateKey [SerializedPrivateKeySize]byte
 }
 
 // SerializedPrivateKey is a byte array representing the storage representation of a PrivateKey
-type SerializedPrivateKey [32]byte
+type SerializedPrivateKey [SerializedPrivateKeySize]byte
 
 // String returns the PrivateKey as the hexadecimal string
 func (key *SerializedPrivateKey) String() string {
@@ -110,6 +115,19 @@ func DeserializePrivateKey(data *SerializedPrivateKey) (key *PrivateKey, err err
 	return &PrivateKey{*data}, nil
 }
 
+// DeserializePrivateKeyFromSlice returns a PrivateKey type from a serialized private key slice.
+// will verify that it's 32 byte and it's a valid private key(Group Order > key > 0)
+func DeserializePrivateKeyFromSlice(data []byte) (key *PrivateKey, err error) {
+	if len(data) != SerializedPrivateKeySize {
+		return nil, errors.Errorf("invalid private key length got %d, expected %d", len(data),
+			SerializedPrivateKeySize)
+	}
+
+	serializedKey := &SerializedPrivateKey{}
+	copy(serializedKey[:], data)
+	return DeserializePrivateKey(serializedKey)
+}
+
 // GeneratePrivateKey generates a random valid private key from `crypto/rand`
 func GeneratePrivateKey() (key *PrivateKey, err error) {
 	key = &PrivateKey{}

secp256k1_test.go

@@ -464,17 +464,21 @@ func TestSchnorrSignatureVerify(t *testing.T) {
 		},
 	}
 
-	sig64 := SerializedSchnorrSignature{}
 	msg32 := Hash{}
 	for i, test := range tests {
 		pubkey, err := DeserializeSchnorrPubKey(test.pubKey)
 		if err != nil {
 			t.Fatal(err)
 		}
-		copy(sig64[:], test.signature)
-		sig := DeserializeSchnorrSignature(&sig64)
+		sig, err := DeserializeSchnorrSignatureFromSlice(test.signature)
+		if err != nil {
+			t.Fatal(err)
+		}
 
-		copy(msg32[:], test.message)
+		err = msg32.SetBytes(test.message)
+		if err != nil {
+			t.Fatal(err)
+		}
 		valid := pubkey.SchnorrVerify(&msg32, sig)
 		if valid != test.valid {
 			t.Errorf("Schnorr test vector '%d' expected verification: '%t', got: '%t'", i, valid, test.valid)
@@ -484,12 +488,17 @@ func TestSchnorrSignatureVerify(t *testing.T) {
 
 func TestDeterministicSchnorrSignatureGen(t *testing.T) {
 	// Test vector from Bitcoin-ABC
-	privKeyBytes := SerializedPrivateKey{}
-	copy(privKeyBytes[:], decodeHex("12b004fff7f4b69ef8650e767f18f11ede158148b425660723b9f9a66e61f747"))
-	privKey, _ := DeserializePrivateKey(&privKeyBytes)
+
+	privKey, err := DeserializePrivateKeyFromSlice(decodeHex("12b004fff7f4b69ef8650e767f18f11ede158148b425660723b9f9a66e61f747"))
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	msg := Hash{}
-	copy(msg[:], decodeHex("5255683da567900bfd3e786ed8836a4e7763c221bf1ac20ece2a5171b9199e8a"))
+	err = msg.SetBytes(decodeHex("5255683da567900bfd3e786ed8836a4e7763c221bf1ac20ece2a5171b9199e8a"))
+	if err != nil {
+		t.Fatal(err)
+	}
 	sig, err := privKey.SchnorrSign(&msg)
 	if err != nil {
 		t.Fatal(err)