crypto: add secp256r1 (#8559)

* Optimize secp256k1 hashing

* Add ADR-028 related functions

* Update ed25519

* fix errors/handle

* fix build

* fix build

* Add tests and update function names

* wip

* Use LengthPrefix for composed addresses

* add tests for NewComposed

* add module hash function

* fix append

* rollback ed25519 ADR-28 update

* rollback ed25519 ADR-28 test

* Adding Module tests and convert tests to test suite

* convert store_key_test.go to test suite

* rollback test check comment

* any.pb.go update

* generated proto files

* wip

* renames

* wip2

* add String method to PBBytes

* wip3

* add pubkey tests

* adding cryptotypes.PrivKey methods

* re-enable test

* fix equals test

* fix ecdsa object receiver

* add ProtoMarshaler implementation and tests

* move code to init and add interface registry

* add bytes tests

* merge Unmarshal with UnmarshalAmino

* implement ProtoMarshaler to ecdsaSK

* remove bytes.go

* add private key marshaling tests

* break tests into 2 suites

* add signature tests

* remove TODO

* remove bytes.proto

* adding changelog

* Update CHANGELOG.md

* Update crypto/keys/ecdsa/ecdsa_privkey.go

* Update crypto/keys/ecdsa/ecdsa_pubkey.go

* comments: add dot (.) at the end

* update comments

* update commented code

* rename files

* remove Amino methods

* use 2 spaces in protocgen.sh

* rollback changes in protocgen.sh

* add MessageName

* rework ecdsa proto structure

* move ecdsa to internal package

* add secp256r1 proto

* refactore proto definition for secp256r1

* fix err check

* update comments

* create const for fieldSize+1

* simplify the PubKey.String test

* Apply suggestions from code review

Co-authored-by: Jonathan Gimeno <jgimeno@gmail.com>

* Update doc comments: SDK Interface -> sdk.Interface

* rename init.go to doc.go

* Add PubKey.Type() test

* Revert "Update doc comments: SDK Interface -> sdk.Interface"

This reverts commit 01f2b4f5efcd79a452483bcda152db54a8fbfee2.

* Use cryptotypes.Address instead of tmcrypto

* Revert "Use cryptotypes.Address instead of tmcrypto"

This reverts commit 15b866ae67bdb7ca4872f4089fcab19f9e2e3608.
This issue will be solved in cosmos/cosmos-sdk#8775

* add link to ANSI X9.62

* move init.go -> doc.go

* use proto.MessageName()

Co-authored-by: Alessio Treglia <alessio@tendermint.com>
Co-authored-by: Jonathan Gimeno <jgimeno@gmail.com>

CHANGELOG.md

@@ -40,6 +40,10 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * [\#8363](https://github.com/cosmos/cosmos-sdk/issues/8363) Addresses no longer have a fixed 20-byte length. From the SDK modules' point of view, any 1-255 bytes-long byte array is a valid address.
 
+## Features
+
+* [\#8559](https://github.com/cosmos/cosmos-sdk/pull/8559) Adding Protobuf compatible secp256r1 ECDSA signatures.
+
 ### Client Breaking Changes
 
 * [\#8363](https://github.com/cosmos/cosmos-sdk/pull/8363) Addresses no longer have a fixed 20-byte length. From the SDK modules' point of view, any 1-255 bytes-long byte array is a valid address.

crypto/codec/proto.go

@@ -5,13 +5,16 @@ import (
 	"github.com/cosmos/cosmos-sdk/crypto/keys/ed25519"
 	"github.com/cosmos/cosmos-sdk/crypto/keys/multisig"
 	"github.com/cosmos/cosmos-sdk/crypto/keys/secp256k1"
+	"github.com/cosmos/cosmos-sdk/crypto/keys/secp256r1"
 	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
 )
 
 // RegisterInterfaces registers the sdk.Tx interface.
 func RegisterInterfaces(registry codectypes.InterfaceRegistry) {
-	registry.RegisterInterface("cosmos.crypto.PubKey", (*cryptotypes.PubKey)(nil))
-	registry.RegisterImplementations((*cryptotypes.PubKey)(nil), &ed25519.PubKey{})
-	registry.RegisterImplementations((*cryptotypes.PubKey)(nil), &secp256k1.PubKey{})
-	registry.RegisterImplementations((*cryptotypes.PubKey)(nil), &multisig.LegacyAminoPubKey{})
+	var pk *cryptotypes.PubKey
+	registry.RegisterInterface("cosmos.crypto.PubKey", pk)
+	registry.RegisterImplementations(pk, &ed25519.PubKey{})
+	registry.RegisterImplementations(pk, &secp256k1.PubKey{})
+	registry.RegisterImplementations(pk, &multisig.LegacyAminoPubKey{})
+	secp256r1.RegisterInterfaces(registry)
 }

crypto/keys/internal/ecdsa/doc.go

@@ -0,0 +1,3 @@
+// Package ECDSA implements Cosmos-SDK compatible ECDSA public and private key. The keys
+// can be serialized.
+package ecdsa

crypto/keys/internal/ecdsa/privkey.go

@@ -0,0 +1,69 @@
+package ecdsa
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/sha256"
+	"fmt"
+	"math/big"
+)
+
+// GenPrivKey generates a new secp256r1 private key. It uses operating system randomness.
+func GenPrivKey(curve elliptic.Curve) (PrivKey, error) {
+	key, err := ecdsa.GenerateKey(curve, rand.Reader)
+	if err != nil {
+		return PrivKey{}, err
+	}
+	return PrivKey{*key}, nil
+}
+
+type PrivKey struct {
+	ecdsa.PrivateKey
+}
+
+// PubKey returns ECDSA public key associated with this private key.
+func (sk *PrivKey) PubKey() PubKey {
+	return PubKey{sk.PublicKey, nil}
+}
+
+// Bytes serialize the private key using big-endian.
+func (sk *PrivKey) Bytes() []byte {
+	if sk == nil {
+		return nil
+	}
+	fieldSize := (sk.Curve.Params().BitSize + 7) / 8
+	bz := make([]byte, fieldSize)
+	sk.D.FillBytes(bz)
+	return bz
+}
+
+// Sign hashes and signs the message usign ECDSA. Implements SDK PrivKey interface.
+func (sk *PrivKey) Sign(msg []byte) ([]byte, error) {
+	digest := sha256.Sum256(msg)
+	return sk.PrivateKey.Sign(rand.Reader, digest[:], nil)
+}
+
+// String returns a string representation of the public key based on the curveName.
+func (sk *PrivKey) String(name string) string {
+	return name + "{-}"
+}
+
+// MarshalTo implements proto.Marshaler interface.
+func (sk *PrivKey) MarshalTo(dAtA []byte) (int, error) {
+	bz := sk.Bytes()
+	copy(dAtA, bz)
+	return len(bz), nil
+}
+
+// Unmarshal implements proto.Marshaler interface.
+func (sk *PrivKey) Unmarshal(bz []byte, curve elliptic.Curve, expectedSize int) error {
+	if len(bz) != expectedSize {
+		return fmt.Errorf("wrong ECDSA SK bytes, expecting %d bytes", expectedSize)
+	}
+
+	sk.Curve = curve
+	sk.D = new(big.Int).SetBytes(bz)
+	sk.X, sk.Y = curve.ScalarBaseMult(bz)
+	return nil
+}

crypto/keys/internal/ecdsa/privkey_internal_test.go

@@ -0,0 +1,66 @@
+package ecdsa
+
+import (
+	"testing"
+
+	"github.com/tendermint/tendermint/crypto"
+
+	"github.com/stretchr/testify/suite"
+)
+
+func TestSKSuite(t *testing.T) {
+	suite.Run(t, new(SKSuite))
+}
+
+type SKSuite struct{ CommonSuite }
+
+func (suite *SKSuite) TestString() {
+	const prefix = "abc"
+	suite.Require().Equal(prefix+"{-}", suite.sk.String(prefix))
+}
+
+func (suite *SKSuite) TestPubKey() {
+	pk := suite.sk.PubKey()
+	suite.True(suite.sk.PublicKey.Equal(&pk.PublicKey))
+}
+
+func (suite *SKSuite) Bytes() {
+	bz := suite.sk.Bytes()
+	suite.Len(bz, 32)
+	var sk *PrivKey
+	suite.Nil(sk.Bytes())
+}
+
+func (suite *SKSuite) TestMarshal() {
+	require := suite.Require()
+	const size = 32
+
+	var buffer = make([]byte, size)
+	suite.sk.MarshalTo(buffer)
+
+	var sk = new(PrivKey)
+	err := sk.Unmarshal(buffer, secp256r1, size)
+	require.NoError(err)
+	require.True(sk.Equal(&suite.sk.PrivateKey))
+}
+
+func (suite *SKSuite) TestSign() {
+	require := suite.Require()
+
+	msg := crypto.CRandBytes(1000)
+	sig, err := suite.sk.Sign(msg)
+	require.NoError(err)
+	sigCpy := make([]byte, len(sig))
+	copy(sigCpy, sig)
+	require.True(suite.pk.VerifySignature(msg, sigCpy))
+
+	// Mutate the signature
+	for i := range sig {
+		sigCpy[i] ^= byte(i + 1)
+		require.False(suite.pk.VerifySignature(msg, sigCpy))
+	}
+
+	// Mutate the message
+	msg[1] ^= byte(2)
+	require.False(suite.pk.VerifySignature(msg, sig))
+}

crypto/keys/internal/ecdsa/pubkey.go

@@ -0,0 +1,83 @@
+package ecdsa
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/sha256"
+	"encoding/asn1"
+	"fmt"
+	"math/big"
+
+	tmcrypto "github.com/tendermint/tendermint/crypto"
+
+	"github.com/cosmos/cosmos-sdk/types/address"
+	"github.com/cosmos/cosmos-sdk/types/errors"
+)
+
+// signature holds the r and s values of an ECDSA signature.
+type signature struct {
+	R, S *big.Int
+}
+
+type PubKey struct {
+	ecdsa.PublicKey
+
+	// cache
+	address tmcrypto.Address
+}
+
+// Address creates an ADR-28 address for ECDSA keys. protoName is a concrete proto structure id.
+func (pk *PubKey) Address(protoName string) tmcrypto.Address {
+	if pk.address == nil {
+		pk.address = address.Hash(protoName, pk.Bytes())
+	}
+	return pk.address
+}
+
+// Bytes returns the byte representation of the public key using a compressed form
+// specified in section 4.3.6 of ANSI X9.62 with first byte being the curve type.
+func (pk *PubKey) Bytes() []byte {
+	if pk == nil {
+		return nil
+	}
+	return elliptic.MarshalCompressed(pk.Curve, pk.X, pk.Y)
+}
+
+// VerifySignature checks if sig is a valid ECDSA signature for msg.
+func (pk *PubKey) VerifySignature(msg []byte, sig []byte) bool {
+	s := new(signature)
+	if _, err := asn1.Unmarshal(sig, s); err != nil || s == nil {
+		return false
+	}
+
+	h := sha256.Sum256(msg)
+	return ecdsa.Verify(&pk.PublicKey, h[:], s.R, s.S)
+}
+
+// String returns a string representation of the public key based on the curveName.
+func (pk *PubKey) String(curveName string) string {
+	return fmt.Sprintf("%s{%X}", curveName, pk.Bytes())
+}
+
+// **** Proto Marshaler ****
+
+// MarshalTo implements proto.Marshaler interface.
+func (pk *PubKey) MarshalTo(dAtA []byte) (int, error) {
+	bz := pk.Bytes()
+	copy(dAtA, bz)
+	return len(bz), nil
+}
+
+// Unmarshal implements proto.Marshaler interface.
+func (pk *PubKey) Unmarshal(bz []byte, curve elliptic.Curve, expectedSize int) error {
+	if len(bz) != expectedSize {
+		return errors.Wrapf(errors.ErrInvalidPubKey, "wrong ECDSA PK bytes, expecting %d bytes, got %d", expectedSize, len(bz))
+	}
+	cpk := ecdsa.PublicKey{Curve: curve}
+	cpk.X, cpk.Y = elliptic.UnmarshalCompressed(curve, bz)
+	if cpk.X == nil || cpk.Y == nil {
+		return errors.Wrapf(errors.ErrInvalidPubKey, "wrong ECDSA PK bytes, unknown curve type: %d", bz[0])
+	}
+	pk.PublicKey = cpk
+	return nil
+}

crypto/keys/internal/ecdsa/pubkey_internal_test.go

@@ -0,0 +1,69 @@
+package ecdsa
+
+import (
+	"crypto/elliptic"
+	"encoding/hex"
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+)
+
+var secp256r1 = elliptic.P256()
+
+func GenSecp256r1() (PrivKey, error) {
+	return GenPrivKey(secp256r1)
+}
+
+func TestPKSuite(t *testing.T) {
+	suite.Run(t, new(PKSuite))
+}
+
+type CommonSuite struct {
+	suite.Suite
+	pk PubKey
+	sk PrivKey
+}
+
+func (suite *CommonSuite) SetupSuite() {
+	sk, err := GenSecp256r1()
+	suite.Require().NoError(err)
+	suite.sk = sk
+	suite.pk = sk.PubKey()
+}
+
+type PKSuite struct{ CommonSuite }
+
+func (suite *PKSuite) TestString() {
+	assert := suite.Assert()
+	require := suite.Require()
+
+	prefix := "abc"
+	pkStr := suite.pk.String(prefix)
+	assert.Equal(prefix+"{", pkStr[:len(prefix)+1])
+	assert.EqualValues('}', pkStr[len(pkStr)-1])
+
+	bz, err := hex.DecodeString(pkStr[len(prefix)+1 : len(pkStr)-1])
+	require.NoError(err)
+	assert.EqualValues(suite.pk.Bytes(), bz)
+}
+
+func (suite *PKSuite) TestBytes() {
+	require := suite.Require()
+	var pk *PubKey
+	require.Nil(pk.Bytes())
+}
+
+func (suite *PKSuite) TestMarshal() {
+	require := suite.Require()
+	const size = 33 // secp256r1 size
+
+	var buffer = make([]byte, size)
+	n, err := suite.pk.MarshalTo(buffer)
+	require.NoError(err)
+	require.Equal(size, n)
+
+	var pk = new(PubKey)
+	err = pk.Unmarshal(buffer, secp256r1, size)
+	require.NoError(err)
+	require.True(pk.PublicKey.Equal(&suite.pk.PublicKey))
+}

crypto/keys/secp256r1/doc.go

@@ -0,0 +1,35 @@
+// Package secp256r1 implements Cosmos-SDK compatible ECDSA public and private key. The keys
+// can be protobuf serialized and packed in Any.
+package secp256r1
+
+import (
+	"crypto/elliptic"
+	"fmt"
+
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
+)
+
+const (
+	// fieldSize is the curve domain size.
+	fieldSize  = 32
+	pubKeySize = fieldSize + 1
+
+	name = "secp256r1"
+)
+
+var secp256r1 elliptic.Curve
+
+func init() {
+	secp256r1 = elliptic.P256()
+	// pubKeySize is ceil of field bit size + 1 for the sign
+	expected := (secp256r1.Params().BitSize + 7) / 8
+	if expected != fieldSize {
+		panic(fmt.Sprintf("Wrong secp256r1 curve fieldSize=%d, expecting=%d", fieldSize, expected))
+	}
+}
+
+// RegisterInterfaces adds secp256r1 PubKey to pubkey registry
+func RegisterInterfaces(registry codectypes.InterfaceRegistry) {
+	registry.RegisterImplementations((*cryptotypes.PubKey)(nil), &PubKey{})
+}