func TestPublicKeyIsEqual(t *testing.T) {
	pubKey1, err := secp256k1.ParsePubKey(
		[]byte{0x03, 0x26, 0x89, 0xc7, 0xc2, 0xda, 0xb1, 0x33,
			0x09, 0xfb, 0x14, 0x3e, 0x0e, 0x8f, 0xe3, 0x96, 0x34,
			0x25, 0x21, 0x88, 0x7e, 0x97, 0x66, 0x90, 0xb6, 0xb4,
			0x7f, 0x5b, 0x2a, 0x4b, 0x7d, 0x44, 0x8e,
		},
		secp256k1.S256(),
	)
	if err != nil {
		t.Fatalf("failed to parse raw bytes for pubKey1: %v", err)
	}

	pubKey2, err := secp256k1.ParsePubKey(
		[]byte{0x02, 0xce, 0x0b, 0x14, 0xfb, 0x84, 0x2b, 0x1b,
			0xa5, 0x49, 0xfd, 0xd6, 0x75, 0xc9, 0x80, 0x75, 0xf1,
			0x2e, 0x9c, 0x51, 0x0f, 0x8e, 0xf5, 0x2b, 0xd0, 0x21,
			0xa9, 0xa1, 0xf4, 0x80, 0x9d, 0x3b, 0x4d,
		},
		secp256k1.S256(),
	)
	if err != nil {
		t.Fatalf("failed to parse raw bytes for pubKey2: %v", err)
	}

	if !pubKey1.IsEqual(pubKey1) {
		t.Fatalf("value of IsEqual is incorrect, %v is "+
			"equal to %v", pubKey1, pubKey1)
	}

	if pubKey1.IsEqual(pubKey2) {
		t.Fatalf("value of IsEqual is incorrect, %v is not "+
			"equal to %v", pubKey1, pubKey2)
	}
}

func TestGenerateSharedSecret(t *testing.T) {
	c := secp256k1.S256()
	privKey1, err := secp256k1.GeneratePrivateKey(secp256k1.S256())
	if err != nil {
		t.Errorf("private key generation error: %s", err)
		return
	}
	privKey2, err := secp256k1.GeneratePrivateKey(secp256k1.S256())
	if err != nil {
		t.Errorf("private key generation error: %s", err)
		return
	}

	pk1x, pk1y := privKey1.Public()
	pk1 := secp256k1.NewPublicKey(c, pk1x, pk1y)
	pk2x, pk2y := privKey2.Public()
	pk2 := secp256k1.NewPublicKey(c, pk2x, pk2y)
	secret1 := secp256k1.GenerateSharedSecret(privKey1, pk2)
	secret2 := secp256k1.GenerateSharedSecret(privKey2, pk1)

	if !bytes.Equal(secret1, secret2) {
		t.Errorf("ECDH failed, secrets mismatch - first: %x, second: %x",
			secret1, secret2)
	}
}

// Test 1: Encryption and decryption
func TestCipheringBasic(t *testing.T) {
	c := secp256k1.S256()
	privkey, err := secp256k1.GeneratePrivateKey(secp256k1.S256())
	if err != nil {
		t.Fatal("failed to generate private key")
	}

	in := []byte("Hey there dude. How are you doing? This is a test.")

	pk1x, pk1y := privkey.Public()
	pk1 := secp256k1.NewPublicKey(c, pk1x, pk1y)
	out, err := secp256k1.Encrypt(pk1, in)
	if err != nil {
		t.Fatal("failed to encrypt:", err)
	}

	dec, err := secp256k1.Decrypt(privkey, out)
	if err != nil {
		t.Fatal("failed to decrypt:", err)
	}

	if !bytes.Equal(in, dec) {
		t.Error("decrypted data doesn't match original")
	}
}

func TestScalarMult(t *testing.T) {
	// Strategy for this test:
	// Get a random exponent from the generator point at first
	// This creates a new point which is used in the next iteration
	// Use another random exponent on the new point.
	// We use BaseMult to verify by multiplying the previous exponent
	// and the new random exponent together (mod N)
	s256 := secp256k1.S256()
	x, y := s256.Gx, s256.Gy
	exponent := big.NewInt(1)
	for i := 0; i < 1024; i++ {
		data := make([]byte, 32)
		_, err := rand.Read(data)
		if err != nil {
			t.Fatalf("failed to read random data at %d", i)
			break
		}
		x, y = s256.ScalarMult(x, y, data)
		exponent.Mul(exponent, new(big.Int).SetBytes(data))
		xWant, yWant := s256.ScalarBaseMult(exponent.Bytes())
		if x.Cmp(xWant) != 0 || y.Cmp(yWant) != 0 {
			t.Fatalf("%d: bad output for %X: got (%X, %X), want (%X, %X)", i, data, x, y, xWant, yWant)
			break
		}
	}
}

func benchmarkSigning(b *testing.B) {
	curve := secp256k1.S256()

	r := rand.New(rand.NewSource(54321))
	msg := []byte{
		0xbe, 0x13, 0xae, 0xf4,
		0xe8, 0xa2, 0x00, 0xb6,
		0x45, 0x81, 0xc4, 0xd1,
		0x0c, 0xf4, 0x1b, 0x5b,
		0xe1, 0xd1, 0x81, 0xa7,
		0xd3, 0xdc, 0x37, 0x55,
		0x58, 0xc1, 0xbd, 0xa2,
		0x98, 0x2b, 0xd9, 0xfb,
	}

	numKeys := 1024
	privKeyList := randPrivKeyList(curve, numKeys)

	for n := 0; n < b.N; n++ {
		randIndex := r.Intn(numKeys - 1)
		_, _, err := Sign(curve, privKeyList[randIndex], msg)
		if err != nil {
			panic("sign failure")
		}
	}
}

// This example demonstrates decrypting a message using a private key that is
// first parsed from raw bytes.
func Example_decryptMessage() {
	// Decode the hex-encoded private key.
	pkBytes, err := hex.DecodeString("a11b0a4e1a132305652ee7a8eb7848f6ad" +
		"5ea381e3ce20a2c086a2e388230811")
	if err != nil {
		fmt.Println(err)
		return
	}

	privKey, _ := secp256k1.PrivKeyFromBytes(secp256k1.S256(), pkBytes)

	ciphertext, err := hex.DecodeString("35f644fbfb208bc71e57684c3c8b437402ca" +
		"002047a2f1b38aa1a8f1d5121778378414f708fe13ebf7b4a7bb74407288c1958969" +
		"00207cf4ac6057406e40f79961c973309a892732ae7a74ee96cd89823913b8b8d650" +
		"a44166dc61ea1c419d47077b748a9c06b8d57af72deb2819d98a9d503efc59fc8307" +
		"d14174f8b83354fac3ff56075162")

	// Try decrypting the message.
	plaintext, err := secp256k1.Decrypt(privKey, ciphertext)
	if err != nil {
		fmt.Println(err)
		return
	}

	fmt.Println(string(plaintext))

	// Output:
	// test message
}

func TestPubKeys(t *testing.T) {
	for _, test := range pubKeyTests {
		pk, err := secp256k1.ParsePubKey(test.key, secp256k1.S256())
		if err != nil {
			if test.isValid {
				t.Errorf("%s pubkey failed when shouldn't %v",
					test.name, err)
			}
			continue
		}
		if !test.isValid {
			t.Errorf("%s counted as valid when it should fail",
				test.name)
			continue
		}
		var pkStr []byte
		switch test.format {
		case secp256k1.TstPubkeyUncompressed:
			pkStr = (*secp256k1.PublicKey)(pk).SerializeUncompressed()
		case secp256k1.TstPubkeyCompressed:
			pkStr = (*secp256k1.PublicKey)(pk).SerializeCompressed()
		case secp256k1.TstPubkeyHybrid:
			pkStr = (*secp256k1.PublicKey)(pk).SerializeHybrid()
		}
		if !bytes.Equal(test.key, pkStr) {
			t.Errorf("%s pubkey: serialized keys do not match.",
				test.name)
			spew.Dump(test.key)
			spew.Dump(pkStr)
		}
	}
}

// This example demonstrates signing a message with a secp256k1 private key that
// is first parsed form raw bytes and serializing the generated signature.
func Example_signMessage() {
	// Decode a hex-encoded private key.
	pkBytes, err := hex.DecodeString("22a47fa09a223f2aa079edf85a7c2d4f87" +
		"20ee63e502ee2869afab7de234b80c")
	if err != nil {
		fmt.Println(err)
		return
	}
	privKey, pubKey := secp256k1.PrivKeyFromBytes(secp256k1.S256(), pkBytes)

	// Sign a message using the private key.
	message := "test message"
	messageHash := chainhash.HashFuncB([]byte(message))
	signature, err := privKey.Sign(messageHash)
	if err != nil {
		fmt.Println(err)
		return
	}

	// Serialize and display the signature.
	fmt.Printf("Serialized Signature: %x\n", signature.Serialize())

	// Verify the signature for the message using the public key.
	verified := signature.Verify(messageHash, pubKey)
	fmt.Printf("Signature Verified? %v\n", verified)

	// Output:
	// Serialized Signature: 3045022100fcc0a8768cfbcefcf2cadd7cfb0fb18ed08dd2e2ae84bef1a474a3d351b26f0302200fc1a350b45f46fa00101391302818d748c2b22615511a3ffd5bb638bd777207
	// Signature Verified? true
}

// This example demonstrates encrypting a message for a public key that is first
// parsed from raw bytes, then decrypting it using the corresponding private key.
func Example_encryptMessage() {
	// Decode the hex-encoded pubkey of the recipient.
	pubKeyBytes, err := hex.DecodeString("04115c42e757b2efb7671c578530ec191a1" +
		"359381e6a71127a9d37c486fd30dae57e76dc58f693bd7e7010358ce6b165e483a29" +
		"21010db67ac11b1b51b651953d2") // uncompressed pubkey
	if err != nil {
		fmt.Println(err)
		return
	}
	pubKey, err := secp256k1.ParsePubKey(pubKeyBytes, secp256k1.S256())
	if err != nil {
		fmt.Println(err)
		return
	}

	// Encrypt a message decryptable by the private key corresponding to pubKey
	message := "test message"
	ciphertext, err := secp256k1.Encrypt(pubKey, []byte(message))
	if err != nil {
		fmt.Println(err)
		return
	}

	// Decode the hex-encoded private key.
	pkBytes, err := hex.DecodeString("a11b0a4e1a132305652ee7a8eb7848f6ad" +
		"5ea381e3ce20a2c086a2e388230811")
	if err != nil {
		fmt.Println(err)
		return
	}
	// note that we already have corresponding pubKey
	privKey, _ := secp256k1.PrivKeyFromBytes(secp256k1.S256(), pkBytes)

	// Try decrypting and verify if it's the same message.
	plaintext, err := secp256k1.Decrypt(privKey, ciphertext)
	if err != nil {
		fmt.Println(err)
		return
	}

	fmt.Println(string(plaintext))

	// Output:
	// test message
}

func TestPrivKeys(t *testing.T) {
	tests := []struct {
		name string
		key  []byte
	}{
		{
			name: "check curve",
			key: []byte{
				0xea, 0xf0, 0x2c, 0xa3, 0x48, 0xc5, 0x24, 0xe6,
				0x39, 0x26, 0x55, 0xba, 0x4d, 0x29, 0x60, 0x3c,
				0xd1, 0xa7, 0x34, 0x7d, 0x9d, 0x65, 0xcf, 0xe9,
				0x3c, 0xe1, 0xeb, 0xff, 0xdc, 0xa2, 0x26, 0x94,
			},
		},
	}

	for _, test := range tests {
		priv, pub := secp256k1.PrivKeyFromBytes(secp256k1.S256(), test.key)

		_, err := secp256k1.ParsePubKey(
			pub.SerializeUncompressed(), secp256k1.S256())
		if err != nil {
			t.Errorf("%s privkey: %v", test.name, err)
			continue
		}

		hash := []byte{0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9}
		sig, err := priv.Sign(hash)
		if err != nil {
			t.Errorf("%s could not sign: %v", test.name, err)
			continue
		}

		if !sig.Verify(hash, pub) {
			t.Errorf("%s could not verify: %v", test.name, err)
			continue
		}

		serializedKey := priv.Serialize()
		if !bytes.Equal(serializedKey, test.key) {
			t.Errorf("%s unexpected serialized bytes - got: %x, "+
				"want: %x", test.name, serializedKey, test.key)
		}
	}
}

// Use our actual hashing algorithm here.
func TestSignaturesAndRecovery(t *testing.T) {
	curve := secp256k1.S256()
	r := rand.New(rand.NewSource(54321))

	numSigs := 128
	sigList := randSigList(curve, numSigs)

	for _, tv := range sigList {
		pubkey := tv.pubkey
		sig := tv.sig

		// Make sure we can verify the original signature.
		_, err := schnorrVerify(curve, sig.Serialize(), pubkey, tv.msg,
			chainhash.HashFuncB)
		assert.NoError(t, err)

		ok := Verify(curve, pubkey, tv.msg, sig.R, sig.S)
		assert.Equal(t, true, ok)

		// See if we can recover the public keys OK.
		var pkRecover *secp256k1.PublicKey
		pkRecover, _, err = schnorrRecover(curve, sig.Serialize(), tv.msg,
			chainhash.HashFuncB)
		assert.NoError(t, err)
		if err == nil {
			assert.Equal(t, pubkey.Serialize(), pkRecover.Serialize())
		}

		// Screw up the signature at some random bits and make sure
		// that breaks it.
		numBadBits := r.Intn(2)
		sigBad := sig.Serialize()
		// (numBadBits*2)+1 --> always odd so at least one bit is different
		for i := 0; i < (numBadBits*2)+1; i++ {
			pos := r.Intn(63)
			bitPos := r.Intn(7)
			sigBad[pos] ^= 1 << uint8(bitPos)
		}
		_, err = schnorrVerify(curve, sigBad, pubkey, tv.msg,
			chainhash.HashFuncB)
		assert.Error(t, err)

		// Make sure it breaks pubkey recovery too.
		valid := false
		pkRecover, valid, err = schnorrRecover(curve, sigBad, tv.msg,
			testSchnorrHash)
		if valid {
			assert.NotEqual(t, pubkey.Serialize(), pkRecover.Serialize())
		} else {
			assert.Error(t, err)
		}
	}
}

func TestSignCompact(t *testing.T) {
	for i := 0; i < 256; i++ {
		name := fmt.Sprintf("test %d", i)
		data := make([]byte, 32)
		_, err := rand.Read(data)
		if err != nil {
			t.Errorf("failed to read random data for %s", name)
			continue
		}
		compressed := i%2 != 0
		testSignCompact(t, name, secp256k1.S256(), data, compressed)
	}
}

// This example demonstrates verifying a secp256k1 signature against a public
// key that is first parsed from raw bytes.  The signature is also parsed from
// raw bytes.
func Example_verifySignature() {
	// Decode hex-encoded serialized public key.
	pubKeyBytes, err := hex.DecodeString("02a673638cb9587cb68ea08dbef685c" +
		"6f2d2a751a8b3c6f2a7e9a4999e6e4bfaf5")
	if err != nil {
		fmt.Println(err)
		return
	}
	pubKey, err := secp256k1.ParsePubKey(pubKeyBytes, secp256k1.S256())
	if err != nil {
		fmt.Println(err)
		return
	}

	// Decode hex-encoded serialized signature.
	sigBytes, err := hex.DecodeString("3045022100fcc0a8768cfbcefcf2cadd7cfb0" +
		"fb18ed08dd2e2ae84bef1a474a3d351b26f0302200fc1a350b45f46fa0010139130" +
		"2818d748c2b22615511a3ffd5bb638bd777207")

	if err != nil {
		fmt.Println(err)
		return
	}
	signature, err := secp256k1.ParseSignature(sigBytes, secp256k1.S256())
	if err != nil {
		fmt.Println(err)
		return
	}

	// Verify the signature for the message using the public key.
	message := "test message"
	messageHash := chainhash.HashFuncB([]byte(message))
	verified := signature.Verify(messageHash, pubKey)
	fmt.Println("Signature Verified?", verified)

	// Output:
	// Signature Verified? true
}

func TestSignatures(t *testing.T) {
	for _, test := range signatureTests {
		var err error
		if test.der {
			_, err = secp256k1.ParseDERSignature(test.sig, secp256k1.S256())
		} else {
			_, err = secp256k1.ParseSignature(test.sig, secp256k1.S256())
		}
		if err != nil {
			if test.isValid {
				t.Errorf("%s signature failed when shouldn't %v",
					test.name, err)
			} /* else {
				t.Errorf("%s got error %v", test.name, err)
			} */
			continue
		}
		if !test.isValid {
			t.Errorf("%s counted as valid when it should fail",
				test.name)
		}
	}
}

func TestSchnorrSigning(t *testing.T) {
	tRand := rand.New(rand.NewSource(54321))
	curve := secp256k1.S256()
	tvs := GetSigningTestVectors()
	for _, tv := range tvs {
		_, pubkey := secp256k1.PrivKeyFromBytes(curve, tv.priv)

		sig, err :=
			schnorrSign(curve, tv.msg, tv.priv, tv.nonce, nil, nil,
				testSchnorrHash)

		assert.NoError(t, err)
		assert.Equal(t, sig.Serialize(), tv.sig)

		// Make sure they verify too while we're at it.
		_, err = schnorrVerify(curve, sig.Serialize(), pubkey, tv.msg,
			testSchnorrHash)
		assert.NoError(t, err)

		// See if we can recover the public keys OK.
		var pkRecover *secp256k1.PublicKey
		pkRecover, _, err = schnorrRecover(curve, sig.Serialize(), tv.msg,
			testSchnorrHash)
		assert.NoError(t, err)
		if err == nil {
			assert.Equal(t, pubkey.Serialize(), pkRecover.Serialize())
		}

		// Screw up the signature at a random bit and make sure that breaks it.
		sigBad := sig.Serialize()
		pos := tRand.Intn(63)
		bitPos := tRand.Intn(7)
		sigBad[pos] ^= 1 << uint8(bitPos)
		_, err = schnorrVerify(curve, sigBad, pubkey, tv.msg,
			testSchnorrHash)
		assert.Error(t, err)

		// Make sure it breaks pubkey recovery too.
		valid := false
		pkRecover, valid, err = schnorrRecover(curve, sigBad, tv.msg,
			testSchnorrHash)
		if valid {
			assert.NotEqual(t, pubkey.Serialize(), pkRecover.Serialize())
		} else {
			assert.Error(t, err)
		}
	}
}

//TODO: test different curves as well?
func TestBaseMult(t *testing.T) {
	s256 := secp256k1.S256()
	for i, e := range s256BaseMultTests {
		k, ok := new(big.Int).SetString(e.k, 16)
		if !ok {
			t.Errorf("%d: bad value for k: %s", i, e.k)
		}
		x, y := s256.ScalarBaseMult(k.Bytes())
		if fmt.Sprintf("%X", x) != e.x || fmt.Sprintf("%X", y) != e.y {
			t.Errorf("%d: bad output for k=%s: got (%X, %X), want (%s, %s)", i, e.k, x, y, e.x, e.y)
		}
		if testing.Short() && i > 5 {
			break
		}
	}
}

func benchmarkVerification(b *testing.B) {
	curve := secp256k1.S256()
	r := rand.New(rand.NewSource(54321))

	numSigs := 1024
	sigList := randSigList(curve, numSigs)

	for n := 0; n < b.N; n++ {
		randIndex := r.Intn(numSigs - 1)
		ver := Verify(curve,
			sigList[randIndex].pubkey,
			sigList[randIndex].msg,
			sigList[randIndex].sig.R,
			sigList[randIndex].sig.S)
		if ver != true {
			panic("made invalid sig")
		}
	}
}

func TestBaseMultVerify(t *testing.T) {
	s256 := secp256k1.S256()
	for bytes := 1; bytes < 40; bytes++ {
		for i := 0; i < 30; i++ {
			data := make([]byte, bytes)
			_, err := rand.Read(data)
			if err != nil {
				t.Errorf("failed to read random data for %d", i)
				continue
			}
			x, y := s256.ScalarBaseMult(data)
			xWant, yWant := s256.ScalarMult(s256.Gx, s256.Gy, data)
			if x.Cmp(xWant) != 0 || y.Cmp(yWant) != 0 {
				t.Errorf("%d: bad output for %X: got (%X, %X), want (%X, %X)", i, data, x, y, xWant, yWant)
			}
			if testing.Short() && i > 2 {
				break
			}
		}
	}
}

// Test 2: Byte compatibility with Pyelliptic
func TestCiphering(t *testing.T) {
	pb, _ := hex.DecodeString("fe38240982f313ae5afb3e904fb8215fb11af1200592b" +
		"fca26c96c4738e4bf8f")
	privkey, _ := secp256k1.PrivKeyFromBytes(secp256k1.S256(), pb)

	in := []byte("This is just a test.")
	out, _ := hex.DecodeString("b0d66e5adaa5ed4e2f0ca68e17b8f2fc02ca002009e3" +
		"3487e7fa4ab505cf34d98f131be7bd258391588ca7804acb30251e71a04e0020ecf" +
		"df0f84608f8add82d7353af780fbb28868c713b7813eb4d4e61f7b75d7534dd9856" +
		"9b0ba77cf14348fcff80fee10e11981f1b4be372d93923e9178972f69937ec850ed" +
		"6c3f11ff572ddd5b2bedf9f9c0b327c54da02a28fcdce1f8369ffec")

	dec, err := secp256k1.Decrypt(privkey, out)
	if err != nil {
		t.Fatal("failed to decrypt:", err)
	}

	if !bytes.Equal(in, dec) {
		t.Error("decrypted data doesn't match original")
	}
}

func GetThresholdTestVectors() []*ThresholdTestVector {
	curve := secp256k1.S256()

	var tvs []*ThresholdTestVector
	for _, v := range thresholdTestVectorsHex {
		msg, _ := hex.DecodeString(v.msg)
		combSig, _ := hex.DecodeString(v.combinedSignature)
		signers := make([]signer, len(v.signersHex), len(v.signersHex))
		for i, signerHex := range v.signersHex {
			privkeyB, _ := hex.DecodeString(signerHex.privkey)
			_, pubkey := secp256k1.PrivKeyFromBytes(curve, privkeyB)
			privateNonceB, _ := hex.DecodeString(signerHex.privateNonce)
			_, noncePub := secp256k1.PrivKeyFromBytes(curve, privateNonceB)
			pubKeySumLocalB, _ := hex.DecodeString(signerHex.pubKeySumLocal)
			pubKeySumLocal, _ := secp256k1.ParsePubKey(pubKeySumLocalB, curve)
			partialSignature, _ := hex.DecodeString(signerHex.partialSignature)

			signers[i].privkey = privkeyB
			signers[i].pubkey = pubkey
			signers[i].privateNonce = privateNonceB
			signers[i].publicNonce = noncePub
			signers[i].pubKeySumLocal = pubKeySumLocal
			signers[i].partialSignature = partialSignature
		}

		lv := ThresholdTestVector{
			msg:               msg,
			signers:           signers,
			combinedSignature: combSig,
		}

		tvs = append(tvs, &lv)
	}

	return tvs
}