feat: Add NewPubKeyFromBytes for secp256r1 to create PubKey from bytes (#24919)

Co-authored-by: Alex | Interchain Labs <alex@interchainlabs.io>

CHANGELOG.md

@@ -49,6 +49,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Features
 
+* (crypto) [#24919](https://github.com/cosmos/cosmos-sdk/pull/24919) add `NewPubKeyFromBytes` function to the `secp256r1` package to create `PubKey` from bytes
 * (server) [#24720](https://github.com/cosmos/cosmos-sdk/pull/24720) add `verbose_log_level` flag for configuring the log level when switching to verbose logging mode during sensitive operations (such as chain upgrades).
 * (crypto) [#24861](https://github.com/cosmos/cosmos-sdk/pull/24861) add `PubKeyFromCometTypeAndBytes` helper function to convert from `comet/v2` PubKeys to the `cryptotypes.Pubkey` interface.
 

crypto/keys/secp256r1/pubkey.go

@@ -6,8 +6,11 @@ import (
 	cmtcrypto "github.com/cometbft/cometbft/v2/crypto"
 	"github.com/cosmos/gogoproto/proto"
 
+	errorsmod "cosmossdk.io/errors"
+
 	ecdsa "github.com/cosmos/cosmos-sdk/crypto/keys/internal/ecdsa"
 	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
+	"github.com/cosmos/cosmos-sdk/types/errors"
 )
 
 // customProtobufType is here to make sure that ecdsaPK and ecdsaSK implement the
@@ -99,3 +102,18 @@ func (pk *ecdsaPK) Size() int {
 func (pk *ecdsaPK) Unmarshal(bz []byte) error {
 	return pk.PubKey.Unmarshal(bz, secp256r1, pubKeySize)
 }
+
+// NewPubKeyFromBytes creates a secp256r1 PubKey from bytes.
+func NewPubKeyFromBytes(bytes []byte) (*PubKey, error) {
+	if len(bytes) != pubKeySize {
+		return nil, errorsmod.Wrapf(errors.ErrInvalidPubKey,
+			"wrong secp256r1 pubkey size, expecting %d bytes, got %d",
+			pubKeySize, len(bytes))
+	}
+	pk := &ecdsaPK{}
+	err := pk.Unmarshal(bytes)
+	if err != nil {
+		return nil, errorsmod.Wrap(errors.ErrInvalidPubKey, err.Error())
+	}
+	return &PubKey{Key: pk}, nil
+}

crypto/keys/secp256r1/pubkey_internal_test.go

@@ -137,3 +137,25 @@ func (suite *PKSuite) TestJson() {
 	require.NoError(pk.UnmarshalJSON(bz))
 	require.Equal(suite.pk.Key, pk)
 }
+
+func (suite *PKSuite) TestNewPubKeyFromBytes() {
+	require := suite.Require()
+
+	originalBytes := suite.pk.Bytes()
+	newPk, err := NewPubKeyFromBytes(originalBytes)
+	require.NoError(err)
+	require.NotNil(newPk)
+	require.True(newPk.Equals(suite.pk))
+	require.Equal(originalBytes, newPk.Bytes())
+
+	_, err = NewPubKeyFromBytes([]byte{1, 2, 3})
+	require.Error(err)
+
+	_, err = NewPubKeyFromBytes(nil)
+	require.Error(err)
+
+	invalidBytes := make([]byte, pubKeySize)
+	invalidBytes[0] = 0x04
+	_, err = NewPubKeyFromBytes(invalidBytes)
+	require.Error(err)
+}