Add PublicKey's Bytes and FromBytes + tests

signature/rsa/rsa.go

@@ -20,7 +20,9 @@ package rsa
 import (
 	"crypto"
 	gorsa "crypto/rsa"
+	"encoding/binary"
 	"io"
+	"math/big"
 
 	"gitlab.com/xx_network/crypto/large"
 	_ "golang.org/x/crypto/blake2b"
@@ -128,6 +130,22 @@ func (p *PrivateKey) GetE() int {
 	return p.E
 }
 
+// Bytes returns the PublicKey as a byte slice.
+func (p *PublicKey) Bytes() []byte {
+	buf := make([]byte, 16)
+	binary.PutVarint(buf, int64(p.GetE()))
+	return append(buf, p.PublicKey.N.Bytes()...)
+}
+
+// FromBytes loads the given byte slice into the PublicKey.
+func (p *PublicKey) FromBytes(b []byte) error {
+	e, _ := binary.Varint(b[:8])
+	p.E = int(e)
+	p.N = new(big.Int)
+	p.N.SetBytes(b[8:])
+	return nil
+}
+
 // GetN returns the RSA Public Key modulus
 func (p *PublicKey) GetN() *large.Int {
 	return large.NewIntFromBigInt(p.N)

signature/rsa/rsa_test.go

@@ -218,3 +218,21 @@ func TestIsValidSignature(t *testing.T) {
 			"\n\t Signer's public key: %+v", len(matchingSig), serverPubKey.Size())
 	}
 }
+
+func TestRSABytesFromBytes(t *testing.T) {
+	serverPrivKey, err := GenerateKey(rand.Reader, 4096)
+	if err != nil {
+		t.Errorf("Failed to generate private key: %+v", err)
+	}
+	serverPubKey := serverPrivKey.GetPublic()
+	serverPubKeyBytes := serverPubKey.Bytes()
+	serverPubKey2 := new(PublicKey)
+	err = serverPubKey2.FromBytes(serverPubKeyBytes)
+	if err != nil {
+		t.Fatal(err)
+	}
+	serverPubKey2Bytes := serverPubKey2.Bytes()
+	if !bytes.Equal(serverPubKeyBytes, serverPubKey2Bytes) {
+		t.Fatal("byte slices don't match")
+	}
+}