Transaction signing and encoding (#95)

* WIP setting up evm tx command and updating emint keys output

* Fix linting issue

* Wip restructuring to allow for ethereum signing and encoding

* WIP setting up keybase and context to use Ethermint keys

* Fixed encoding and decoding of emint keys

* Adds command for generating explicit ethereum tx

* Fixed evm route for handling tx

* Fixed tx and msg encoding which allows transactions to be sent

* Added relevant documentation for changes and cleaned up code

* Added documentation and indicators why code was overriden

crypto/encoding/amino.go

@@ -0,0 +1,35 @@
+package encoding
+
+import (
+	emintcrypto "github.com/cosmos/ethermint/crypto"
+	amino "github.com/tendermint/go-amino"
+	tmcrypto "github.com/tendermint/tendermint/crypto"
+)
+
+var cdc = amino.NewCodec()
+
+func init() {
+	RegisterAmino(cdc)
+}
+
+// RegisterAmino registers all crypto related types in the given (amino) codec.
+func RegisterAmino(cdc *amino.Codec) {
+	// These are all written here instead of
+	cdc.RegisterInterface((*tmcrypto.PubKey)(nil), nil)
+	cdc.RegisterConcrete(emintcrypto.PubKeySecp256k1{}, emintcrypto.PubKeyAminoName, nil)
+
+	cdc.RegisterInterface((*tmcrypto.PrivKey)(nil), nil)
+	cdc.RegisterConcrete(emintcrypto.PrivKeySecp256k1{}, emintcrypto.PrivKeyAminoName, nil)
+}
+
+// PrivKeyFromBytes unmarshalls emint private key from encoded bytes
+func PrivKeyFromBytes(privKeyBytes []byte) (privKey tmcrypto.PrivKey, err error) {
+	err = cdc.UnmarshalBinaryBare(privKeyBytes, &privKey)
+	return
+}
+
+// PubKeyFromBytes unmarshalls emint public key from encoded bytes
+func PubKeyFromBytes(pubKeyBytes []byte) (pubKey tmcrypto.PubKey, err error) {
+	err = cdc.UnmarshalBinaryBare(pubKeyBytes, &pubKey)
+	return
+}

crypto/encoding/amino_test.go

@@ -0,0 +1,28 @@
+package encoding
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	emintcrypto "github.com/cosmos/ethermint/crypto"
+)
+
+func TestKeyEncodingDecoding(t *testing.T) {
+	// Priv Key encoding and decoding
+	privKey, err := emintcrypto.GenerateKey()
+	require.NoError(t, err)
+	privBytes := privKey.Bytes()
+
+	decodedPriv, err := PrivKeyFromBytes(privBytes)
+	require.NoError(t, err)
+	require.Equal(t, privKey, decodedPriv)
+
+	// Pub key encoding and decoding
+	pubKey := privKey.PubKey()
+	pubBytes := pubKey.Bytes()
+
+	decodedPub, err := PubKeyFromBytes(pubBytes)
+	require.NoError(t, err)
+	require.Equal(t, pubKey, decodedPub)
+}