diff --git a/client/tx/legacy.go b/client/tx/legacy.go
index 2648a520c..71f0fe8c4 100644
--- a/client/tx/legacy.go
+++ b/client/tx/legacy.go
@@ -6,28 +6,28 @@ import (
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/types"
 )
 
 // ConvertTxToStdTx converts a transaction to the legacy StdTx format
-func ConvertTxToStdTx(codec *codec.LegacyAmino, tx signing.Tx) (types.StdTx, error) {
-	if stdTx, ok := tx.(types.StdTx); ok {
+func ConvertTxToStdTx(codec *codec.LegacyAmino, tx signing.Tx) (legacytx.StdTx, error) {
+	if stdTx, ok := tx.(legacytx.StdTx); ok {
 		return stdTx, nil
 	}
 
-	aminoTxConfig := types.StdTxConfig{Cdc: codec}
+	aminoTxConfig := legacytx.StdTxConfig{Cdc: codec}
 	builder := aminoTxConfig.NewTxBuilder()
 
 	err := CopyTx(tx, builder)
 	if err != nil {
 
-		return types.StdTx{}, err
+		return legacytx.StdTx{}, err
 	}
 
-	stdTx, ok := builder.GetTx().(types.StdTx)
+	stdTx, ok := builder.GetTx().(legacytx.StdTx)
 	if !ok {
-		return types.StdTx{}, fmt.Errorf("expected %T, got %+v", types.StdTx{}, builder.GetTx())
+		return legacytx.StdTx{}, fmt.Errorf("expected %T, got %+v", legacytx.StdTx{}, builder.GetTx())
 	}
 
 	return stdTx, nil
@@ -58,13 +58,13 @@ func CopyTx(tx signing.Tx, builder client.TxBuilder) error {
 	return nil
 }
 
-func ConvertAndEncodeStdTx(txConfig client.TxConfig, stdTx types.StdTx) ([]byte, error) {
+func ConvertAndEncodeStdTx(txConfig client.TxConfig, stdTx legacytx.StdTx) ([]byte, error) {
 	builder := txConfig.NewTxBuilder()
 
 	var theTx sdk.Tx
 
 	// check if we need a StdTx anyway, in that case don't copy
-	if _, ok := builder.GetTx().(types.StdTx); ok {
+	if _, ok := builder.GetTx().(legacytx.StdTx); ok {
 		theTx = stdTx
 	} else {
 		err := CopyTx(stdTx, builder)
diff --git a/client/tx/legacy_test.go b/client/tx/legacy_test.go
index 786ebc767..4884faa83 100644
--- a/client/tx/legacy_test.go
+++ b/client/tx/legacy_test.go
@@ -14,10 +14,10 @@ import (
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
 	"github.com/cosmos/cosmos-sdk/types"
 	signing2 "github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 	"github.com/cosmos/cosmos-sdk/x/auth/tx"
-	types3 "github.com/cosmos/cosmos-sdk/x/auth/types"
-	types2 "github.com/cosmos/cosmos-sdk/x/bank/types"
+	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 )
 
 const (
@@ -29,7 +29,7 @@ var (
 	fee            = types.NewCoins(types.NewInt64Coin("bam", 100))
 	_, pub1, addr1 = testdata.KeyTestPubAddr()
 	_, _, addr2    = testdata.KeyTestPubAddr()
-	msg            = types2.NewMsgSend(addr1, addr2, types.NewCoins(types.NewInt64Coin("wack", 10000)))
+	msg            = banktypes.NewMsgSend(addr1, addr2, types.NewCoins(types.NewInt64Coin("wack", 10000)))
 	sig            = signing2.SignatureV2{
 		PubKey: pub1,
 		Data: &signing2.SingleSignatureData{
@@ -60,7 +60,7 @@ func (s *TestSuite) SetupSuite() {
 	encCfg := simapp.MakeEncodingConfig()
 	s.encCfg = encCfg
 	s.protoCfg = tx.NewTxConfig(codec.NewProtoCodec(encCfg.InterfaceRegistry), tx.DefaultSignModes)
-	s.aminoCfg = types3.StdTxConfig{Cdc: encCfg.Amino}
+	s.aminoCfg = legacytx.StdTxConfig{Cdc: encCfg.Amino}
 }
 
 func (s *TestSuite) TestCopyTx() {
@@ -111,7 +111,7 @@ func (s *TestSuite) TestConvertTxToStdTx() {
 	// std tx
 	aminoBuilder := s.aminoCfg.NewTxBuilder()
 	buildTestTx(s.T(), aminoBuilder)
-	stdTx = aminoBuilder.GetTx().(types3.StdTx)
+	stdTx = aminoBuilder.GetTx().(legacytx.StdTx)
 	stdTx2, err := tx2.ConvertTxToStdTx(s.encCfg.Amino, stdTx)
 	s.Require().NoError(err)
 	s.Require().Equal(stdTx, stdTx2)
@@ -121,7 +121,7 @@ func (s *TestSuite) TestConvertAndEncodeStdTx() {
 	// convert amino -> proto -> amino
 	aminoBuilder := s.aminoCfg.NewTxBuilder()
 	buildTestTx(s.T(), aminoBuilder)
-	stdTx := aminoBuilder.GetTx().(types3.StdTx)
+	stdTx := aminoBuilder.GetTx().(legacytx.StdTx)
 	txBz, err := tx2.ConvertAndEncodeStdTx(s.protoCfg, stdTx)
 	s.Require().NoError(err)
 	decodedTx, err := s.protoCfg.TxDecoder()(txBz)
diff --git a/crypto/keys/multisig/multisig_test.go b/crypto/keys/multisig/multisig_test.go
index d04531b94..96ed9a612 100644
--- a/crypto/keys/multisig/multisig_test.go
+++ b/crypto/keys/multisig/multisig_test.go
@@ -8,7 +8,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/codec/types"
 	crypto "github.com/cosmos/cosmos-sdk/crypto/types"
 	"github.com/cosmos/cosmos-sdk/crypto/types/multisig"
-	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 
 	"github.com/stretchr/testify/require"
 
@@ -262,8 +262,8 @@ func TestMultiSigMigration(t *testing.T) {
 	err := multisig.AddSignatureFromPubKey(multisignature, sigs[0], pkSet[0], pkSet)
 
 	// create a StdSignature for msg, and convert it to sigV2
-	sig := authtypes.StdSignature{PubKey: pkSet[1], Signature: msg}
-	sigV2, err := authtypes.StdSignatureToSignatureV2(cdc, sig)
+	sig := legacytx.StdSignature{PubKey: pkSet[1], Signature: msg}
+	sigV2, err := legacytx.StdSignatureToSignatureV2(cdc, sig)
 	require.NoError(t, multisig.AddSignatureV2(multisignature, sigV2, pkSet))
 
 	require.NoError(t, err)
diff --git a/simapp/params/amino.go b/simapp/params/amino.go
index 67ee2d54d..ff9b05a9f 100644
--- a/simapp/params/amino.go
+++ b/simapp/params/amino.go
@@ -5,7 +5,7 @@ package params
 import (
 	"github.com/cosmos/cosmos-sdk/codec"
 	"github.com/cosmos/cosmos-sdk/codec/types"
-	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 )
 
 // MakeEncodingConfig creates an EncodingConfig for an amino based test configuration.
@@ -17,7 +17,7 @@ func MakeEncodingConfig() EncodingConfig {
 	return EncodingConfig{
 		InterfaceRegistry: interfaceRegistry,
 		Marshaler:         marshaler,
-		TxConfig:          authtypes.StdTxConfig{Cdc: cdc},
+		TxConfig:          legacytx.StdTxConfig{Cdc: cdc},
 		Amino:             cdc,
 	}
 }
diff --git a/x/auth/ante/ante_test.go b/x/auth/ante/ante_test.go
index 670985f78..1fd13e77f 100644
--- a/x/auth/ante/ante_test.go
+++ b/x/auth/ante/ante_test.go
@@ -954,7 +954,7 @@ func TestCountSubkeys(t *testing.T) {
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(T *testing.T) {
-			require.Equal(t, tc.want, types.CountSubKeys(tc.args.pub))
+			require.Equal(t, tc.want, ante.CountSubKeys(tc.args.pub))
 		})
 	}
 }
diff --git a/x/auth/ante/basic.go b/x/auth/ante/basic.go
index b73b95656..f722e51a0 100644
--- a/x/auth/ante/basic.go
+++ b/x/auth/ante/basic.go
@@ -8,12 +8,8 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	authsigning "github.com/cosmos/cosmos-sdk/x/auth/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/types"
-)
-
-var (
-	_ sdk.TxWithMemo = (*types.StdTx)(nil) // assert StdTx implements TxWithMemo
 )
 
 // ValidateBasicDecorator will call tx.ValidateBasic and return any non-nil error.
@@ -79,7 +75,7 @@ func (vmd ValidateMemoDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate
 // CONTRACT: If simulate=true, then signatures must either be completely filled
 // in or empty.
 // CONTRACT: To use this decorator, signatures of transaction must be represented
-// as types.StdSignature otherwise simulate mode will incorrectly estimate gas cost.
+// as legacytx.StdSignature otherwise simulate mode will incorrectly estimate gas cost.
 type ConsumeTxSizeGasDecorator struct {
 	ak AccountKeeper
 }
@@ -126,7 +122,7 @@ func (cgts ConsumeTxSizeGasDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, sim
 			}
 
 			// use stdsignature to mock the size of a full signature
-			simSig := types.StdSignature{ //nolint:staticcheck // this will be removed when proto is ready
+			simSig := legacytx.StdSignature{ //nolint:staticcheck // this will be removed when proto is ready
 				Signature: simSecp256k1Sig[:],
 				PubKey:    pubkey,
 			}
diff --git a/x/auth/ante/fee.go b/x/auth/ante/fee.go
index 47ef35b73..5da4dbbaf 100644
--- a/x/auth/ante/fee.go
+++ b/x/auth/ante/fee.go
@@ -8,10 +8,6 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/auth/types"
 )
 
-var (
-	_ sdk.FeeTx = (*types.StdTx)(nil) // assert StdTx implements FeeTx
-)
-
 // MempoolFeeDecorator will check if the transaction's fee is at least as large
 // as the local validator's minimum gasFee (defined in validator config).
 // If fee is too low, decorator returns error and tx is rejected from mempool.
diff --git a/x/auth/ante/setup.go b/x/auth/ante/setup.go
index 1e3e8eb68..5f21aba8b 100644
--- a/x/auth/ante/setup.go
+++ b/x/auth/ante/setup.go
@@ -5,11 +5,11 @@ import (
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-	"github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 )
 
 var (
-	_ GasTx = (*types.StdTx)(nil) // assert StdTx implements GasTx
+	_ GasTx = (*legacytx.StdTx)(nil) // assert StdTx implements GasTx
 )
 
 // GasTx defines a Tx with a GetGas() method which is needed to use SetUpContextDecorator
diff --git a/x/auth/ante/sigverify.go b/x/auth/ante/sigverify.go
index 05bc583b1..4c091bb94 100644
--- a/x/auth/ante/sigverify.go
+++ b/x/auth/ante/sigverify.go
@@ -5,13 +5,16 @@ import (
 	"encoding/hex"
 	"fmt"
 
+	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
 
+	kmultisig "github.com/cosmos/cosmos-sdk/crypto/keys/multisig"
 	"github.com/cosmos/cosmos-sdk/crypto/keys/secp256k1"
 	"github.com/cosmos/cosmos-sdk/crypto/types/multisig"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	authsigning "github.com/cosmos/cosmos-sdk/x/auth/signing"
 	"github.com/cosmos/cosmos-sdk/x/auth/types"
 )
@@ -22,7 +25,7 @@ var (
 	simSecp256k1Pubkey = &secp256k1.PubKey{Key: key}
 	simSecp256k1Sig    [64]byte
 
-	_ authsigning.SigVerifiableTx = (*types.StdTx)(nil) // assert StdTx implements SigVerifiableTx
+	_ authsigning.SigVerifiableTx = (*legacytx.StdTx)(nil) // assert StdTx implements SigVerifiableTx
 )
 
 func init() {
@@ -340,7 +343,7 @@ func (vscd ValidateSigCountDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, sim
 
 	sigCount := 0
 	for _, pk := range pubKeys {
-		sigCount += types.CountSubKeys(pk)
+		sigCount += CountSubKeys(pk)
 		if uint64(sigCount) > params.TxSigLimit {
 			return ctx, sdkerrors.Wrapf(sdkerrors.ErrTooManySignatures,
 				"signatures: %d, limit: %d", sigCount, params.TxSigLimit)
@@ -420,3 +423,18 @@ func GetSignerAcc(ctx sdk.Context, ak AccountKeeper, addr sdk.AccAddress) (types
 
 	return nil, sdkerrors.Wrapf(sdkerrors.ErrUnknownAddress, "account %s does not exist", addr)
 }
+
+// CountSubKeys counts the total number of keys for a multi-sig public key.
+func CountSubKeys(pub crypto.PubKey) int {
+	v, ok := pub.(*kmultisig.LegacyAminoPubKey)
+	if !ok {
+		return 1
+	}
+
+	numKeys := 0
+	for _, subkey := range v.GetPubKeys() {
+		numKeys += CountSubKeys(subkey)
+	}
+
+	return numKeys
+}
diff --git a/x/auth/ante/sigverify_test.go b/x/auth/ante/sigverify_test.go
index 58d1dea8b..3144a1f9c 100644
--- a/x/auth/ante/sigverify_test.go
+++ b/x/auth/ante/sigverify_test.go
@@ -16,8 +16,8 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
 	"github.com/cosmos/cosmos-sdk/x/auth/ante"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/types"
-	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
 )
 
 func (suite *AnteTestSuite) TestSetPubKey() {
@@ -75,8 +75,8 @@ func (suite *AnteTestSuite) TestConsumeSignatureVerificationGas() {
 	multisignature1 := multisig.NewMultisig(len(pkSet1))
 	expectedCost1 := expectedGasCostByKeys(pkSet1)
 	for i := 0; i < len(pkSet1); i++ {
-		stdSig := types.StdSignature{PubKey: pkSet1[i], Signature: sigSet1[i]}
-		sigV2, err := types.StdSignatureToSignatureV2(cdc, stdSig)
+		stdSig := legacytx.StdSignature{PubKey: pkSet1[i], Signature: sigSet1[i]}
+		sigV2, err := legacytx.StdSignatureToSignatureV2(cdc, stdSig)
 		suite.Require().NoError(err)
 		err = multisig.AddSignatureV2(multisignature1, sigV2, pkSet1)
 		suite.Require().NoError(err)
@@ -196,7 +196,7 @@ func (suite *AnteTestSuite) TestSigVerification_ExplicitAmino() {
 	// Set up TxConfig.
 	aminoCdc := codec.NewLegacyAmino()
 	// We're using TestMsg amino encoding in some tests, so register it here.
-	txConfig := authtypes.StdTxConfig{Cdc: aminoCdc}
+	txConfig := legacytx.StdTxConfig{Cdc: aminoCdc}
 
 	suite.clientCtx = client.Context{}.
 		WithTxConfig(txConfig)
diff --git a/x/auth/client/rest/broadcast.go b/x/auth/client/rest/broadcast.go
index 37daf5084..e0020515d 100644
--- a/x/auth/client/rest/broadcast.go
+++ b/x/auth/client/rest/broadcast.go
@@ -8,13 +8,13 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/types/rest"
-	"github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 )
 
 // BroadcastReq defines a tx broadcasting request.
 type BroadcastReq struct {
-	Tx   types.StdTx `json:"tx" yaml:"tx"`
-	Mode string      `json:"mode" yaml:"mode"`
+	Tx   legacytx.StdTx `json:"tx" yaml:"tx"`
+	Mode string         `json:"mode" yaml:"mode"`
 }
 
 // BroadcastTxRequest implements a tx broadcasting handler that is responsible
diff --git a/x/auth/client/rest/decode.go b/x/auth/client/rest/decode.go
index f42cc09c4..ca72487a8 100644
--- a/x/auth/client/rest/decode.go
+++ b/x/auth/client/rest/decode.go
@@ -11,7 +11,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/client"
 	clienttx "github.com/cosmos/cosmos-sdk/client/tx"
 	"github.com/cosmos/cosmos-sdk/types/rest"
-	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 )
 
 type (
@@ -21,7 +21,7 @@ type (
 	}
 
 	// DecodeResp defines a tx decoding response.
-	DecodeResp authtypes.StdTx
+	DecodeResp legacytx.StdTx
 )
 
 // DecodeTxRequestHandlerFn returns the decode tx REST handler. In particular,
@@ -61,21 +61,21 @@ func DecodeTxRequestHandlerFn(clientCtx client.Context) http.HandlerFunc {
 // convertToStdTx converts tx proto binary bytes retrieved from Tendermint into
 // a StdTx. Returns the StdTx, as well as a flag denoting if the function
 // successfully converted or not.
-func convertToStdTx(w http.ResponseWriter, clientCtx client.Context, txBytes []byte) (authtypes.StdTx, bool) {
+func convertToStdTx(w http.ResponseWriter, clientCtx client.Context, txBytes []byte) (legacytx.StdTx, bool) {
 	txI, err := clientCtx.TxConfig.TxDecoder()(txBytes)
 	if rest.CheckBadRequestError(w, err) {
-		return authtypes.StdTx{}, false
+		return legacytx.StdTx{}, false
 	}
 
 	tx, ok := txI.(signing.Tx)
 	if !ok {
-		rest.WriteErrorResponse(w, http.StatusBadRequest, fmt.Sprintf("%+v is not backwards compatible with %T", tx, authtypes.StdTx{}))
-		return authtypes.StdTx{}, false
+		rest.WriteErrorResponse(w, http.StatusBadRequest, fmt.Sprintf("%+v is not backwards compatible with %T", tx, legacytx.StdTx{}))
+		return legacytx.StdTx{}, false
 	}
 
 	stdTx, err := clienttx.ConvertTxToStdTx(clientCtx.LegacyAmino, tx)
 	if rest.CheckBadRequestError(w, err) {
-		return authtypes.StdTx{}, false
+		return legacytx.StdTx{}, false
 	}
 
 	return stdTx, true
diff --git a/x/auth/client/rest/encode.go b/x/auth/client/rest/encode.go
index e3930a1f8..1fbc3b94f 100644
--- a/x/auth/client/rest/encode.go
+++ b/x/auth/client/rest/encode.go
@@ -9,7 +9,7 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/types/rest"
-	"github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 )
 
 // EncodeResp defines a tx encoding response.
@@ -22,7 +22,7 @@ type EncodeResp struct {
 // and responds with base64-encoded bytes.
 func EncodeTxRequestHandlerFn(clientCtx client.Context) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		var req types.StdTx
+		var req legacytx.StdTx
 
 		body, err := ioutil.ReadAll(r.Body)
 		if rest.CheckBadRequestError(w, err) {
diff --git a/x/auth/client/rest/rest_test.go b/x/auth/client/rest/rest_test.go
index de3c8fee2..7ae6fe824 100644
--- a/x/auth/client/rest/rest_test.go
+++ b/x/auth/client/rest/rest_test.go
@@ -15,7 +15,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
 	authclient "github.com/cosmos/cosmos-sdk/x/auth/client"
 	rest2 "github.com/cosmos/cosmos-sdk/x/auth/client/rest"
-	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/bank/types"
 )
 
@@ -44,57 +44,53 @@ func (s *IntegrationTestSuite) TearDownSuite() {
 	s.network.Cleanup()
 }
 
-func (s *IntegrationTestSuite) TestEncodeDecode() {
-	val := s.network.Validators[0]
-
+func mkTx() legacytx.StdTx {
 	// NOTE: this uses StdTx explicitly, don't migrate it!
-	stdTx := authtypes.StdTx{
+	return legacytx.StdTx{
 		Msgs: []sdk.Msg{&types.MsgSend{}},
-		Fee: authtypes.StdFee{
+		Fee: legacytx.StdFee{
 			Amount: sdk.Coins{sdk.NewInt64Coin("foo", 10)},
 			Gas:    10000,
 		},
 		Memo: "FOOBAR",
 	}
+}
+
+func (s *IntegrationTestSuite) TestEncodeDecode() {
+	var require = s.Require()
+	val := s.network.Validators[0]
+	stdTx := mkTx()
 
 	// NOTE: this uses amino explicitly, don't migrate it!
 	cdc := val.ClientCtx.LegacyAmino
 
 	bz, err := cdc.MarshalJSON(stdTx)
-	s.Require().NoError(err)
+	require.NoError(err)
 
 	res, err := rest.PostRequest(fmt.Sprintf("%s/txs/encode", val.APIAddress), "application/json", bz)
-	s.Require().NoError(err)
+	require.NoError(err)
 
 	var encodeResp rest2.EncodeResp
 	err = cdc.UnmarshalJSON(res, &encodeResp)
-	s.Require().NoError(err)
+	require.NoError(err)
 
 	bz, err = cdc.MarshalJSON(rest2.DecodeReq{Tx: encodeResp.Tx})
-	s.Require().NoError(err)
+	require.NoError(err)
 
 	res, err = rest.PostRequest(fmt.Sprintf("%s/txs/decode", val.APIAddress), "application/json", bz)
-	s.Require().NoError(err)
+	require.NoError(err)
 
 	var respWithHeight rest.ResponseWithHeight
 	err = cdc.UnmarshalJSON(res, &respWithHeight)
-	s.Require().NoError(err)
+	require.NoError(err)
 	var decodeResp rest2.DecodeResp
 	err = cdc.UnmarshalJSON(respWithHeight.Result, &decodeResp)
-	s.Require().NoError(err)
-	s.Require().Equal(stdTx, authtypes.StdTx(decodeResp))
+	require.NoError(err)
+	require.Equal(stdTx, legacytx.StdTx(decodeResp))
 }
 
 func (s *IntegrationTestSuite) TestBroadcastTxRequest() {
-	// NOTE: this uses StdTx explicitly, don't migrate it!
-	stdTx := authtypes.StdTx{
-		Msgs: []sdk.Msg{&types.MsgSend{}},
-		Fee: authtypes.StdFee{
-			Amount: sdk.Coins{sdk.NewInt64Coin("foo", 10)},
-			Gas:    10000,
-		},
-		Memo: "FOOBAR",
-	}
+	stdTx := mkTx()
 
 	// we just test with async mode because this tx will fail - all we care about is that it got encoded and broadcast correctly
 	res, err := s.broadcastReq(stdTx, "async")
@@ -182,8 +178,8 @@ func (s *IntegrationTestSuite) TestMultipleSyncBroadcastTxRequests() {
 	}
 }
 
-func (s *IntegrationTestSuite) createTestStdTx(val *network.Validator, sequence uint64) authtypes.StdTx {
-	txConfig := authtypes.StdTxConfig{Cdc: s.cfg.LegacyAmino}
+func (s *IntegrationTestSuite) createTestStdTx(val *network.Validator, sequence uint64) legacytx.StdTx {
+	txConfig := legacytx.StdTxConfig{Cdc: s.cfg.LegacyAmino}
 
 	msg := &types.MsgSend{
 		FromAddress: val.Address,
@@ -212,17 +208,16 @@ func (s *IntegrationTestSuite) createTestStdTx(val *network.Validator, sequence
 	err := authclient.SignTx(txFactory, val.ClientCtx, val.Moniker, txBuilder, true)
 	s.Require().NoError(err)
 
-	stdTx := txBuilder.GetTx().(authtypes.StdTx)
+	stdTx := txBuilder.GetTx().(legacytx.StdTx)
 
 	return stdTx
 }
 
-func (s *IntegrationTestSuite) broadcastReq(stdTx authtypes.StdTx, mode string) ([]byte, error) {
+func (s *IntegrationTestSuite) broadcastReq(stdTx legacytx.StdTx, mode string) ([]byte, error) {
 	val := s.network.Validators[0]
 
 	// NOTE: this uses amino explicitly, don't migrate it!
 	cdc := val.ClientCtx.LegacyAmino
-
 	req := rest2.BroadcastReq{
 		Tx:   stdTx,
 		Mode: mode,
diff --git a/x/auth/client/tx.go b/x/auth/client/tx.go
index e3af34132..79570d519 100644
--- a/x/auth/client/tx.go
+++ b/x/auth/client/tx.go
@@ -16,7 +16,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 )
 
 // Codec defines the x/auth account codec to be used for use with the
@@ -156,7 +156,7 @@ func populateAccountFromState(
 func GetTxEncoder(cdc *codec.LegacyAmino) (encoder sdk.TxEncoder) {
 	encoder = sdk.GetConfig().GetTxEncoder()
 	if encoder == nil {
-		encoder = authtypes.DefaultTxEncoder(cdc)
+		encoder = legacytx.DefaultTxEncoder(cdc)
 	}
 
 	return encoder
diff --git a/x/auth/client/tx_test.go b/x/auth/client/tx_test.go
index bf433f1e3..e87ce21a3 100644
--- a/x/auth/client/tx_test.go
+++ b/x/auth/client/tx_test.go
@@ -5,20 +5,18 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/stretchr/testify/require"
 	"github.com/tendermint/tendermint/crypto/ed25519"
 
+	"github.com/cosmos/cosmos-sdk/client"
+	"github.com/cosmos/cosmos-sdk/codec"
+	cryptocodec "github.com/cosmos/cosmos-sdk/crypto/codec"
 	"github.com/cosmos/cosmos-sdk/simapp"
 	"github.com/cosmos/cosmos-sdk/testutil"
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
-	authclient "github.com/cosmos/cosmos-sdk/x/auth/client"
-
-	"github.com/cosmos/cosmos-sdk/client"
-
-	"github.com/stretchr/testify/require"
-
-	"github.com/cosmos/cosmos-sdk/codec"
-	cryptocodec "github.com/cosmos/cosmos-sdk/crypto/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	authclient "github.com/cosmos/cosmos-sdk/x/auth/client"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
 )
 
@@ -49,7 +47,7 @@ func TestParseQueryResponse(t *testing.T) {
 func TestDefaultTxEncoder(t *testing.T) {
 	cdc := makeCodec()
 
-	defaultEncoder := authtypes.DefaultTxEncoder(cdc)
+	defaultEncoder := legacytx.DefaultTxEncoder(cdc)
 	encoder := authclient.GetTxEncoder(cdc)
 
 	compareEncoders(t, defaultEncoder, encoder)
@@ -142,7 +140,7 @@ func TestBatchScanner_Scan(t *testing.T) {
 
 func compareEncoders(t *testing.T, expected sdk.TxEncoder, actual sdk.TxEncoder) {
 	msgs := []sdk.Msg{testdata.NewTestMsg(addr)}
-	tx := authtypes.NewStdTx(msgs, authtypes.StdFee{}, []authtypes.StdSignature{}, "")
+	tx := legacytx.NewStdTx(msgs, legacytx.StdFee{}, []legacytx.StdSignature{}, "")
 
 	defaultEncoderBytes, err := expected(tx)
 	require.NoError(t, err)
diff --git a/x/auth/legacy/legacytx/amino_signing.go b/x/auth/legacy/legacytx/amino_signing.go
new file mode 100644
index 000000000..d09b1b30a
--- /dev/null
+++ b/x/auth/legacy/legacytx/amino_signing.go
@@ -0,0 +1,91 @@
+package legacytx
+
+import (
+	"fmt"
+
+	"github.com/cosmos/cosmos-sdk/codec"
+	"github.com/cosmos/cosmos-sdk/crypto/types/multisig"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	signingtypes "github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/cosmos/cosmos-sdk/x/auth/signing"
+)
+
+// stdTxSignModeHandler is a SignModeHandler that handles SIGN_MODE_LEGACY_AMINO_JSON
+type stdTxSignModeHandler struct{}
+
+func NewStdTxSignModeHandler() signing.SignModeHandler {
+	return &stdTxSignModeHandler{}
+}
+
+// assert interface implementation
+var _ signing.SignModeHandler = stdTxSignModeHandler{}
+
+// DefaultMode implements SignModeHandler.DefaultMode
+func (h stdTxSignModeHandler) DefaultMode() signingtypes.SignMode {
+	return signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON
+}
+
+// Modes implements SignModeHandler.Modes
+func (stdTxSignModeHandler) Modes() []signingtypes.SignMode {
+	return []signingtypes.SignMode{signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON}
+}
+
+// DefaultMode implements SignModeHandler.GetSignBytes
+func (stdTxSignModeHandler) GetSignBytes(mode signingtypes.SignMode, data signing.SignerData, tx sdk.Tx) ([]byte, error) {
+	if mode != signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON {
+		return nil, fmt.Errorf("expected %s, got %s", signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON, mode)
+	}
+
+	stdTx, ok := tx.(StdTx)
+	if !ok {
+		return nil, fmt.Errorf("expected %T, got %T", StdTx{}, tx)
+	}
+
+	return StdSignBytes(
+		data.ChainID, data.AccountNumber, data.Sequence, stdTx.GetTimeoutHeight(), StdFee{Amount: stdTx.GetFee(), Gas: stdTx.GetGas()}, tx.GetMsgs(), stdTx.GetMemo(),
+	), nil
+}
+
+// SignatureDataToAminoSignature converts a SignatureData to amino-encoded signature bytes.
+// Only SIGN_MODE_LEGACY_AMINO_JSON is supported.
+func SignatureDataToAminoSignature(cdc *codec.LegacyAmino, data signingtypes.SignatureData) ([]byte, error) {
+	switch data := data.(type) {
+	case *signingtypes.SingleSignatureData:
+		if data.SignMode != signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON {
+			return nil, fmt.Errorf("wrong SignMode. Expected %s, got %s",
+				signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON, data.SignMode)
+		}
+
+		return data.Signature, nil
+	case *signingtypes.MultiSignatureData:
+		aminoMSig, err := MultiSignatureDataToAminoMultisignature(cdc, data)
+		if err != nil {
+			return nil, err
+		}
+
+		return cdc.MarshalBinaryBare(aminoMSig)
+	default:
+		return nil, fmt.Errorf("unexpected signature data %T", data)
+	}
+}
+
+// MultiSignatureDataToAminoMultisignature converts a MultiSignatureData to an AminoMultisignature.
+// Only SIGN_MODE_LEGACY_AMINO_JSON is supported.
+func MultiSignatureDataToAminoMultisignature(cdc *codec.LegacyAmino, mSig *signingtypes.MultiSignatureData) (multisig.AminoMultisignature, error) {
+	n := len(mSig.Signatures)
+	sigs := make([][]byte, n)
+
+	for i := 0; i < n; i++ {
+		var err error
+		sigs[i], err = SignatureDataToAminoSignature(cdc, mSig.Signatures[i])
+		if err != nil {
+			return multisig.AminoMultisignature{}, sdkerrors.Wrapf(err, "Unable to convert Signature Data to signature %d", i)
+		}
+	}
+
+	return multisig.AminoMultisignature{
+		BitArray: mSig.BitArray,
+		Sigs:     sigs,
+	}, nil
+}
diff --git a/x/auth/types/amino_signing_test.go b/x/auth/legacy/legacytx/amino_signing_test.go
similarity index 99%
rename from x/auth/types/amino_signing_test.go
rename to x/auth/legacy/legacytx/amino_signing_test.go
index a436f0b22..7abccbfd8 100644
--- a/x/auth/types/amino_signing_test.go
+++ b/x/auth/legacy/legacytx/amino_signing_test.go
@@ -1,4 +1,4 @@
-package types
+package legacytx
 
 import (
 	"testing"
diff --git a/x/auth/legacy/legacytx/codec.go b/x/auth/legacy/legacytx/codec.go
new file mode 100644
index 000000000..2bad4718e
--- /dev/null
+++ b/x/auth/legacy/legacytx/codec.go
@@ -0,0 +1,9 @@
+package legacytx
+
+import (
+	"github.com/cosmos/cosmos-sdk/codec"
+)
+
+func RegisterLegacyAminoCodec(cdc *codec.LegacyAmino) {
+	cdc.RegisterConcrete(StdTx{}, "cosmos-sdk/StdTx", nil)
+}
diff --git a/x/auth/types/client_tx_test.go b/x/auth/legacy/legacytx/config_test.go
similarity index 84%
rename from x/auth/types/client_tx_test.go
rename to x/auth/legacy/legacytx/config_test.go
index 2acdf0f97..95a37b1e4 100644
--- a/x/auth/types/client_tx_test.go
+++ b/x/auth/legacy/legacytx/config_test.go
@@ -1,4 +1,4 @@
-package types_test
+package legacytx_test
 
 import (
 	"testing"
@@ -9,8 +9,8 @@ import (
 	cryptoAmino "github.com/cosmos/cosmos-sdk/crypto/codec"
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/testutil"
-	"github.com/cosmos/cosmos-sdk/x/auth/types"
 )
 
 func testCodec() *codec.LegacyAmino {
@@ -23,6 +23,6 @@ func testCodec() *codec.LegacyAmino {
 
 func TestStdTxConfig(t *testing.T) {
 	cdc := testCodec()
-	txGen := types.StdTxConfig{Cdc: cdc}
+	txGen := legacytx.StdTxConfig{Cdc: cdc}
 	suite.Run(t, testutil.NewTxConfigTestSuite(txGen))
 }
diff --git a/x/auth/legacy/legacytx/stdsign.go b/x/auth/legacy/legacytx/stdsign.go
new file mode 100644
index 000000000..ee44171be
--- /dev/null
+++ b/x/auth/legacy/legacytx/stdsign.go
@@ -0,0 +1,112 @@
+package legacytx
+
+import (
+	"encoding/json"
+
+	"github.com/cosmos/cosmos-sdk/codec"
+	"github.com/cosmos/cosmos-sdk/codec/legacy"
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	"github.com/cosmos/cosmos-sdk/crypto/types/multisig"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	"github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/tendermint/tendermint/crypto"
+)
+
+// Interface implementation checks
+var _ codectypes.UnpackInterfacesMessage = StdTx{}
+
+// StdSignDoc is replay-prevention structure.
+// It includes the result of msg.GetSignBytes(),
+// as well as the ChainID (prevent cross chain replay)
+// and the Sequence numbers for each signature (prevent
+// inchain replay and enforce tx ordering per account).
+type StdSignDoc struct {
+	AccountNumber uint64            `json:"account_number" yaml:"account_number"`
+	Sequence      uint64            `json:"sequence" yaml:"sequence"`
+	TimeoutHeight uint64            `json:"timeout_height,omitempty" yaml:"timeout_height"`
+	ChainID       string            `json:"chain_id" yaml:"chain_id"`
+	Memo          string            `json:"memo" yaml:"memo"`
+	Fee           json.RawMessage   `json:"fee" yaml:"fee"`
+	Msgs          []json.RawMessage `json:"msgs" yaml:"msgs"`
+}
+
+// StdSignBytes returns the bytes to sign for a transaction.
+func StdSignBytes(chainID string, accnum, sequence, timeout uint64, fee StdFee, msgs []sdk.Msg, memo string) []byte {
+	msgsBytes := make([]json.RawMessage, 0, len(msgs))
+	for _, msg := range msgs {
+		msgsBytes = append(msgsBytes, json.RawMessage(msg.GetSignBytes()))
+	}
+
+	bz, err := legacy.Cdc.MarshalJSON(StdSignDoc{
+		AccountNumber: accnum,
+		ChainID:       chainID,
+		Fee:           json.RawMessage(fee.Bytes()),
+		Memo:          memo,
+		Msgs:          msgsBytes,
+		Sequence:      sequence,
+		TimeoutHeight: timeout,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	return sdk.MustSortJSON(bz)
+}
+
+// Deprecated: StdSignature represents a sig
+type StdSignature struct {
+	crypto.PubKey `json:"pub_key" yaml:"pub_key"` // optional
+	Signature     []byte                          `json:"signature" yaml:"signature"`
+}
+
+// StdSignatureToSignatureV2 converts a StdSignature to a SignatureV2
+func StdSignatureToSignatureV2(cdc *codec.LegacyAmino, sig StdSignature) (signing.SignatureV2, error) {
+	pk := sig.GetPubKey()
+	data, err := pubKeySigToSigData(cdc, pk, sig.Signature)
+	if err != nil {
+		return signing.SignatureV2{}, err
+	}
+
+	return signing.SignatureV2{
+		PubKey: pk,
+		Data:   data,
+	}, nil
+}
+
+func pubKeySigToSigData(cdc *codec.LegacyAmino, key crypto.PubKey, sig []byte) (signing.SignatureData, error) {
+	multiPK, ok := key.(multisig.PubKey)
+	if !ok {
+		return &signing.SingleSignatureData{
+			SignMode:  signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON,
+			Signature: sig,
+		}, nil
+	}
+	var multiSig multisig.AminoMultisignature
+	err := cdc.UnmarshalBinaryBare(sig, &multiSig)
+	if err != nil {
+		return nil, err
+	}
+
+	sigs := multiSig.Sigs
+	sigDatas := make([]signing.SignatureData, len(sigs))
+	pubKeys := multiPK.GetPubKeys()
+	bitArray := multiSig.BitArray
+	n := multiSig.BitArray.Count()
+	signatures := multisig.NewMultisig(n)
+	sigIdx := 0
+	for i := 0; i < n; i++ {
+		if bitArray.GetIndex(i) {
+			data, err := pubKeySigToSigData(cdc, pubKeys[i], multiSig.Sigs[sigIdx])
+			if err != nil {
+				return nil, sdkerrors.Wrapf(err, "Unable to convert Signature to SigData %d", sigIdx)
+			}
+
+			sigDatas[sigIdx] = data
+			multisig.AddSignature(signatures, data, sigIdx)
+			sigIdx++
+		}
+	}
+
+	return signatures, nil
+}
diff --git a/x/auth/types/stdsignmsg.go b/x/auth/legacy/legacytx/stdsignmsg.go
similarity index 98%
rename from x/auth/types/stdsignmsg.go
rename to x/auth/legacy/legacytx/stdsignmsg.go
index b7d5e0718..07ee29a06 100644
--- a/x/auth/types/stdsignmsg.go
+++ b/x/auth/legacy/legacytx/stdsignmsg.go
@@ -1,4 +1,4 @@
-package types
+package legacytx
 
 import (
 	"github.com/cosmos/cosmos-sdk/codec/types"
diff --git a/x/auth/legacy/legacytx/stdtx.go b/x/auth/legacy/legacytx/stdtx.go
new file mode 100644
index 000000000..81d670e74
--- /dev/null
+++ b/x/auth/legacy/legacytx/stdtx.go
@@ -0,0 +1,274 @@
+package legacytx
+
+import (
+	"fmt"
+
+	"github.com/cosmos/cosmos-sdk/codec/legacy"
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	txtypes "github.com/cosmos/cosmos-sdk/types/tx"
+	"github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/tendermint/tendermint/crypto"
+	"gopkg.in/yaml.v2"
+)
+
+// Interface implementation checks
+var (
+	_ sdk.Tx             = (*StdTx)(nil)
+	_ codectypes.IntoAny = (*StdTx)(nil)
+	_ sdk.TxWithMemo     = (*StdTx)(nil)
+	_ sdk.FeeTx          = (*StdTx)(nil)
+)
+
+// StdFee includes the amount of coins paid in fees and the maximum
+// gas to be used by the transaction. The ratio yields an effective "gasprice",
+// which must be above some miminum to be accepted into the mempool.
+// [Deprecated]
+type StdFee struct {
+	Amount sdk.Coins `json:"amount" yaml:"amount"`
+	Gas    uint64    `json:"gas" yaml:"gas"`
+}
+
+// Deprecated: NewStdFee returns a new instance of StdFee
+func NewStdFee(gas uint64, amount sdk.Coins) StdFee {
+	return StdFee{
+		Amount: amount,
+		Gas:    gas,
+	}
+}
+
+// GetGas returns the fee's (wanted) gas.
+func (fee StdFee) GetGas() uint64 {
+	return fee.Gas
+}
+
+// GetAmount returns the fee's amount.
+func (fee StdFee) GetAmount() sdk.Coins {
+	return fee.Amount
+}
+
+// Bytes returns the encoded bytes of a StdFee.
+func (fee StdFee) Bytes() []byte {
+	if len(fee.Amount) == 0 {
+		fee.Amount = sdk.NewCoins()
+	}
+
+	bz, err := legacy.Cdc.MarshalJSON(fee)
+	if err != nil {
+		panic(err)
+	}
+
+	return bz
+}
+
+// GasPrices returns the gas prices for a StdFee.
+//
+// NOTE: The gas prices returned are not the true gas prices that were
+// originally part of the submitted transaction because the fee is computed
+// as fee = ceil(gasWanted * gasPrices).
+func (fee StdFee) GasPrices() sdk.DecCoins {
+	return sdk.NewDecCoinsFromCoins(fee.Amount...).QuoDec(sdk.NewDec(int64(fee.Gas)))
+}
+
+// Deprecated
+func NewStdSignature(pk crypto.PubKey, sig []byte) StdSignature {
+	return StdSignature{PubKey: pk, Signature: sig}
+}
+
+// GetSignature returns the raw signature bytes.
+func (ss StdSignature) GetSignature() []byte {
+	return ss.Signature
+}
+
+// GetPubKey returns the public key of a signature as a crypto.PubKey using the
+// Amino codec.
+func (ss StdSignature) GetPubKey() crypto.PubKey {
+	return ss.PubKey
+}
+
+// MarshalYAML returns the YAML representation of the signature.
+func (ss StdSignature) MarshalYAML() (interface{}, error) {
+	var (
+		bz     []byte
+		pubkey string
+		err    error
+	)
+
+	if ss.PubKey != nil {
+		pubkey, err = sdk.Bech32ifyPubKey(sdk.Bech32PubKeyTypeAccPub, ss.GetPubKey())
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	bz, err = yaml.Marshal(struct {
+		PubKey    string
+		Signature string
+	}{
+		PubKey:    pubkey,
+		Signature: fmt.Sprintf("%X", ss.Signature),
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return string(bz), err
+}
+
+// StdTx is the legacy transaction format for wrapping a Msg with Fee and Signatures.
+// It only works with Amino, please prefer the new protobuf Tx in types/tx.
+// NOTE: the first signature is the fee payer (Signatures must not be nil).
+// Deprecated
+type StdTx struct {
+	Msgs          []sdk.Msg      `json:"msg" yaml:"msg"`
+	Fee           StdFee         `json:"fee" yaml:"fee"`
+	Signatures    []StdSignature `json:"signatures" yaml:"signatures"`
+	Memo          string         `json:"memo" yaml:"memo"`
+	TimeoutHeight uint64         `json:"timeout_height" yaml:"timeout_height"`
+}
+
+// Deprecated
+func NewStdTx(msgs []sdk.Msg, fee StdFee, sigs []StdSignature, memo string) StdTx {
+	return StdTx{
+		Msgs:       msgs,
+		Fee:        fee,
+		Signatures: sigs,
+		Memo:       memo,
+	}
+}
+
+// GetMsgs returns the all the transaction's messages.
+func (tx StdTx) GetMsgs() []sdk.Msg { return tx.Msgs }
+
+// ValidateBasic does a simple and lightweight validation check that doesn't
+// require access to any other information.
+func (tx StdTx) ValidateBasic() error {
+	stdSigs := tx.GetSignatures()
+
+	if tx.Fee.Gas > txtypes.MaxGasWanted {
+		return sdkerrors.Wrapf(
+			sdkerrors.ErrInvalidRequest,
+			"invalid gas supplied; %d > %d", tx.Fee.Gas, txtypes.MaxGasWanted,
+		)
+	}
+	if tx.Fee.Amount.IsAnyNegative() {
+		return sdkerrors.Wrapf(
+			sdkerrors.ErrInsufficientFee,
+			"invalid fee provided: %s", tx.Fee.Amount,
+		)
+	}
+	if len(stdSigs) == 0 {
+		return sdkerrors.ErrNoSignatures
+	}
+	if len(stdSigs) != len(tx.GetSigners()) {
+		return sdkerrors.Wrapf(
+			sdkerrors.ErrUnauthorized,
+			"wrong number of signers; expected %d, got %d", len(tx.GetSigners()), len(stdSigs),
+		)
+	}
+
+	return nil
+}
+
+// AsAny implements IntoAny.AsAny.
+func (tx *StdTx) AsAny() *codectypes.Any {
+	return codectypes.UnsafePackAny(tx)
+}
+
+// GetSigners returns the addresses that must sign the transaction.
+// Addresses are returned in a deterministic order.
+// They are accumulated from the GetSigners method for each Msg
+// in the order they appear in tx.GetMsgs().
+// Duplicate addresses will be omitted.
+func (tx StdTx) GetSigners() []sdk.AccAddress {
+	var signers []sdk.AccAddress
+	seen := map[string]bool{}
+
+	for _, msg := range tx.GetMsgs() {
+		for _, addr := range msg.GetSigners() {
+			if !seen[addr.String()] {
+				signers = append(signers, addr)
+				seen[addr.String()] = true
+			}
+		}
+	}
+
+	return signers
+}
+
+// GetMemo returns the memo
+func (tx StdTx) GetMemo() string { return tx.Memo }
+
+// GetTimeoutHeight returns the transaction's timeout height (if set).
+func (tx StdTx) GetTimeoutHeight() uint64 {
+	return tx.TimeoutHeight
+}
+
+// GetSignatures returns the signature of signers who signed the Msg.
+// CONTRACT: Length returned is same as length of
+// pubkeys returned from MsgKeySigners, and the order
+// matches.
+// CONTRACT: If the signature is missing (ie the Msg is
+// invalid), then the corresponding signature is
+// .Empty().
+func (tx StdTx) GetSignatures() [][]byte {
+	sigs := make([][]byte, len(tx.Signatures))
+	for i, stdSig := range tx.Signatures {
+		sigs[i] = stdSig.Signature
+	}
+	return sigs
+}
+
+// GetSignaturesV2 implements SigVerifiableTx.GetSignaturesV2
+func (tx StdTx) GetSignaturesV2() ([]signing.SignatureV2, error) {
+	res := make([]signing.SignatureV2, len(tx.Signatures))
+
+	for i, sig := range tx.Signatures {
+		var err error
+		res[i], err = StdSignatureToSignatureV2(legacy.Cdc, sig)
+		if err != nil {
+			return nil, sdkerrors.Wrapf(err, "Unable to convert signature %v to V2", sig)
+		}
+	}
+
+	return res, nil
+}
+
+// GetPubkeys returns the pubkeys of signers if the pubkey is included in the signature
+// If pubkey is not included in the signature, then nil is in the slice instead
+func (tx StdTx) GetPubKeys() []crypto.PubKey {
+	pks := make([]crypto.PubKey, len(tx.Signatures))
+
+	for i, stdSig := range tx.Signatures {
+		pks[i] = stdSig.GetPubKey()
+	}
+
+	return pks
+}
+
+// GetGas returns the Gas in StdFee
+func (tx StdTx) GetGas() uint64 { return tx.Fee.Gas }
+
+// GetFee returns the FeeAmount in StdFee
+func (tx StdTx) GetFee() sdk.Coins { return tx.Fee.Amount }
+
+// FeePayer returns the address that is responsible for paying fee
+// StdTx returns the first signer as the fee payer
+// If no signers for tx, return empty address
+func (tx StdTx) FeePayer() sdk.AccAddress {
+	if tx.GetSigners() != nil {
+		return tx.GetSigners()[0]
+	}
+	return sdk.AccAddress{}
+}
+
+func (tx StdTx) UnpackInterfaces(unpacker codectypes.AnyUnpacker) error {
+	for _, m := range tx.Msgs {
+		err := codectypes.UnpackInterfaces(m, unpacker)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
diff --git a/x/auth/types/client_tx.go b/x/auth/legacy/legacytx/stdtx_builder.go
similarity index 67%
rename from x/auth/types/client_tx.go
rename to x/auth/legacy/legacytx/stdtx_builder.go
index 04b289376..1b1a55c04 100644
--- a/x/auth/types/client_tx.go
+++ b/x/auth/legacy/legacytx/stdtx_builder.go
@@ -1,4 +1,4 @@
-package types
+package legacytx
 
 import (
 	"fmt"
@@ -6,6 +6,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
 	authsigning "github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
@@ -18,6 +19,7 @@ type StdTxBuilder struct {
 	cdc *codec.LegacyAmino
 }
 
+// ensure interface implementation
 var _ client.TxBuilder = &StdTxBuilder{}
 
 // GetTx implements TxBuilder.GetTx
@@ -34,14 +36,12 @@ func (s *StdTxBuilder) SetMsgs(msgs ...sdk.Msg) error {
 // SetSignatures implements TxBuilder.SetSignatures.
 func (s *StdTxBuilder) SetSignatures(signatures ...signing.SignatureV2) error {
 	sigs := make([]StdSignature, len(signatures))
-
+	var err error
 	for i, sig := range signatures {
-		stdSig, err := SignatureV2ToStdSignature(s.cdc, sig)
+		sigs[i], err = SignatureV2ToStdSignature(s.cdc, sig)
 		if err != nil {
 			return err
 		}
-
-		sigs[i] = stdSig
 	}
 
 	s.Signatures = sigs
@@ -85,7 +85,7 @@ func (s StdTxConfig) NewTxBuilder() client.TxBuilder {
 func (s StdTxConfig) WrapTxBuilder(newTx sdk.Tx) (client.TxBuilder, error) {
 	stdTx, ok := newTx.(StdTx)
 	if !ok {
-		return nil, fmt.Errorf("expected %T, got %T", StdTx{}, newTx)
+		return nil, fmt.Errorf("wrong type, expected %T, got %T", stdTx, newTx)
 	}
 	return &StdTxBuilder{StdTx: stdTx, cdc: s.Cdc}, nil
 }
@@ -96,7 +96,7 @@ func (s StdTxConfig) TxEncoder() sdk.TxEncoder {
 }
 
 func (s StdTxConfig) TxDecoder() sdk.TxDecoder {
-	return DefaultTxDecoder(s.Cdc)
+	return mkDecoder(s.Cdc.UnmarshalBinaryBare)
 }
 
 func (s StdTxConfig) TxJSONEncoder() sdk.TxEncoder {
@@ -106,7 +106,7 @@ func (s StdTxConfig) TxJSONEncoder() sdk.TxEncoder {
 }
 
 func (s StdTxConfig) TxJSONDecoder() sdk.TxDecoder {
-	return DefaultJSONTxDecoder(s.Cdc)
+	return mkDecoder(s.Cdc.UnmarshalJSON)
 }
 
 func (s StdTxConfig) MarshalSignatureJSON(sigs []signing.SignatureV2) ([]byte, error) {
@@ -144,3 +144,50 @@ func (s StdTxConfig) UnmarshalSignatureJSON(bz []byte) ([]signing.SignatureV2, e
 func (s StdTxConfig) SignModeHandler() authsigning.SignModeHandler {
 	return stdTxSignModeHandler{}
 }
+
+// SignatureV2ToStdSignature converts a SignatureV2 to a StdSignature
+// [Deprecated]
+func SignatureV2ToStdSignature(cdc *codec.LegacyAmino, sig signing.SignatureV2) (StdSignature, error) {
+	var (
+		sigBz []byte
+		err   error
+	)
+
+	if sig.Data != nil {
+		sigBz, err = SignatureDataToAminoSignature(cdc, sig.Data)
+		if err != nil {
+			return StdSignature{}, err
+		}
+	}
+
+	return StdSignature{
+		PubKey:    sig.PubKey,
+		Signature: sigBz,
+	}, nil
+}
+
+// Unmarshaler is a generic type for Unmarshal functions
+type Unmarshaler func(bytes []byte, ptr interface{}) error
+
+func mkDecoder(unmarshaler Unmarshaler) sdk.TxDecoder {
+	return func(txBytes []byte) (sdk.Tx, error) {
+		if len(txBytes) == 0 {
+			return nil, sdkerrors.Wrap(sdkerrors.ErrTxDecode, "tx bytes are empty")
+		}
+		var tx = StdTx{}
+		// StdTx.Msg is an interface. The concrete types
+		// are registered by MakeTxCodec
+		err := unmarshaler(txBytes, &tx)
+		if err != nil {
+			return nil, sdkerrors.Wrap(sdkerrors.ErrTxDecode, err.Error())
+		}
+		return tx, nil
+	}
+}
+
+// DefaultTxEncoder logic for standard transaction encoding
+func DefaultTxEncoder(cdc *codec.LegacyAmino) sdk.TxEncoder {
+	return func(tx sdk.Tx) ([]byte, error) {
+		return cdc.MarshalBinaryBare(tx)
+	}
+}
diff --git a/x/auth/types/stdtx_test.go b/x/auth/legacy/legacytx/stdtx_test.go
similarity index 98%
rename from x/auth/types/stdtx_test.go
rename to x/auth/legacy/legacytx/stdtx_test.go
index 86bf72441..cc73db03d 100644
--- a/x/auth/types/stdtx_test.go
+++ b/x/auth/legacy/legacytx/stdtx_test.go
@@ -1,4 +1,4 @@
-package types
+package legacytx
 
 import (
 	"fmt"
@@ -26,6 +26,11 @@ var (
 	addr = sdk.AccAddress(priv.PubKey().Address())
 )
 
+func init() {
+	var amino = codec.NewLegacyAmino()
+	RegisterLegacyAminoCodec(amino)
+}
+
 // Deprecated, use fee amount and gas limit separately on TxBuilder.
 func NewTestStdFee() StdFee {
 	return NewStdFee(100000,
@@ -156,7 +161,6 @@ func TestTxValidateBasic(t *testing.T) {
 func TestDefaultTxEncoder(t *testing.T) {
 	cdc := codec.NewLegacyAmino()
 	sdk.RegisterLegacyAminoCodec(cdc)
-	RegisterLegacyAminoCodec(cdc)
 	cdc.RegisterConcrete(testdata.TestMsg{}, "cosmos-sdk/Test", nil)
 	encoder := DefaultTxEncoder(cdc)
 
@@ -207,7 +211,6 @@ func TestSignatureV2Conversions(t *testing.T) {
 	_, pubKey, _ := testdata.KeyTestPubAddr()
 	cdc := codec.NewLegacyAmino()
 	sdk.RegisterLegacyAminoCodec(cdc)
-	RegisterLegacyAminoCodec(cdc)
 	dummy := []byte("dummySig")
 	sig := StdSignature{PubKey: pubKey, Signature: dummy}
 
@@ -265,7 +268,6 @@ func TestGetSignaturesV2(t *testing.T) {
 	cdc := codec.NewLegacyAmino()
 	sdk.RegisterLegacyAminoCodec(cdc)
 	cryptocodec.RegisterCrypto(cdc)
-	RegisterLegacyAminoCodec(cdc)
 
 	fee := NewStdFee(50000, sdk.Coins{sdk.NewInt64Coin("atom", 150)})
 	sig := StdSignature{PubKey: pubKey, Signature: dummy}
diff --git a/x/auth/signing/handler_map_test.go b/x/auth/signing/handler_map_test.go
index 35a2f022d..6ca405661 100644
--- a/x/auth/signing/handler_map_test.go
+++ b/x/auth/signing/handler_map_test.go
@@ -8,8 +8,8 @@ import (
 	"github.com/cosmos/cosmos-sdk/crypto/keys/secp256k1"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	signingtypes "github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
-	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 )
 
@@ -17,7 +17,7 @@ func MakeTestHandlerMap() signing.SignModeHandler {
 	return signing.NewSignModeHandlerMap(
 		signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON,
 		[]signing.SignModeHandler{
-			authtypes.NewStdTxSignModeHandler(),
+			legacytx.NewStdTxSignModeHandler(),
 		},
 	)
 }
@@ -30,7 +30,7 @@ func TestHandlerMap_GetSignBytes(t *testing.T) {
 
 	coins := sdk.Coins{sdk.NewInt64Coin("foocoin", 10)}
 
-	fee := authtypes.StdFee{
+	fee := legacytx.StdFee{
 		Amount: coins,
 		Gas:    10000,
 	}
@@ -43,7 +43,7 @@ func TestHandlerMap_GetSignBytes(t *testing.T) {
 		},
 	}
 
-	tx := authtypes.StdTx{
+	tx := legacytx.StdTx{
 		Msgs:       msgs,
 		Fee:        fee,
 		Signatures: nil,
@@ -57,7 +57,7 @@ func TestHandlerMap_GetSignBytes(t *testing.T) {
 	)
 
 	handler := MakeTestHandlerMap()
-	aminoJSONHandler := authtypes.NewStdTxSignModeHandler()
+	aminoJSONHandler := legacytx.NewStdTxSignModeHandler()
 
 	signingData := signing.SignerData{
 		ChainID:       chainId,
diff --git a/x/auth/signing/verify_test.go b/x/auth/signing/verify_test.go
index c5bc0be31..351fa0138 100644
--- a/x/auth/signing/verify_test.go
+++ b/x/auth/signing/verify_test.go
@@ -14,6 +14,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/auth/ante"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 	"github.com/cosmos/cosmos-sdk/x/auth/types"
 )
@@ -44,22 +45,22 @@ func TestVerifySignature(t *testing.T) {
 	require.NoError(t, app.BankKeeper.SetBalances(ctx, addr, balances))
 
 	msgs := []sdk.Msg{testdata.NewTestMsg(addr)}
-	fee := types.NewStdFee(50000, sdk.Coins{sdk.NewInt64Coin("atom", 150)})
+	fee := legacytx.NewStdFee(50000, sdk.Coins{sdk.NewInt64Coin("atom", 150)})
 	signerData := signing.SignerData{
 		ChainID:       chainId,
 		AccountNumber: acc.GetAccountNumber(),
 		Sequence:      acc.GetSequence(),
 	}
-	signBytes := types.StdSignBytes(signerData.ChainID, signerData.AccountNumber, signerData.Sequence, 10, fee, msgs, memo)
+	signBytes := legacytx.StdSignBytes(signerData.ChainID, signerData.AccountNumber, signerData.Sequence, 10, fee, msgs, memo)
 	signature, err := priv.Sign(signBytes)
 	require.NoError(t, err)
 
-	stdSig := types.StdSignature{PubKey: pubKey, Signature: signature}
-	sigV2, err := types.StdSignatureToSignatureV2(cdc, stdSig)
+	stdSig := legacytx.StdSignature{PubKey: pubKey, Signature: signature}
+	sigV2, err := legacytx.StdSignatureToSignatureV2(cdc, stdSig)
 	require.NoError(t, err)
 
 	handler := MakeTestHandlerMap()
-	stdTx := types.NewStdTx(msgs, fee, []types.StdSignature{stdSig}, memo)
+	stdTx := legacytx.NewStdTx(msgs, fee, []legacytx.StdSignature{stdSig}, memo)
 	stdTx.TimeoutHeight = 10
 	err = signing.VerifySignature(pubKey, signerData, sigV2.Data, handler, stdTx)
 	require.NoError(t, err)
@@ -68,18 +69,18 @@ func TestVerifySignature(t *testing.T) {
 	multisigKey := kmultisig.NewLegacyAminoPubKey(2, pkSet)
 	multisignature := multisig.NewMultisig(2)
 	msgs = []sdk.Msg{testdata.NewTestMsg(addr, addr1)}
-	multiSignBytes := types.StdSignBytes(signerData.ChainID, signerData.AccountNumber, signerData.Sequence, 10, fee, msgs, memo)
+	multiSignBytes := legacytx.StdSignBytes(signerData.ChainID, signerData.AccountNumber, signerData.Sequence, 10, fee, msgs, memo)
 
 	sig1, err := priv.Sign(multiSignBytes)
 	require.NoError(t, err)
-	stdSig1 := types.StdSignature{PubKey: pubKey, Signature: sig1}
-	sig1V2, err := types.StdSignatureToSignatureV2(cdc, stdSig1)
+	stdSig1 := legacytx.StdSignature{PubKey: pubKey, Signature: sig1}
+	sig1V2, err := legacytx.StdSignatureToSignatureV2(cdc, stdSig1)
 	require.NoError(t, err)
 
 	sig2, err := priv1.Sign(multiSignBytes)
 	require.NoError(t, err)
-	stdSig2 := types.StdSignature{PubKey: pubKey, Signature: sig2}
-	sig2V2, err := types.StdSignatureToSignatureV2(cdc, stdSig2)
+	stdSig2 := legacytx.StdSignature{PubKey: pubKey, Signature: sig2}
+	sig2V2, err := legacytx.StdSignatureToSignatureV2(cdc, stdSig2)
 	require.NoError(t, err)
 
 	err = multisig.AddSignatureFromPubKey(multisignature, sig1V2.Data, pkSet[0], pkSet)
diff --git a/x/auth/testutil/suite.go b/x/auth/testutil/suite.go
index cafc57884..518e502de 100644
--- a/x/auth/testutil/suite.go
+++ b/x/auth/testutil/suite.go
@@ -226,6 +226,7 @@ func sigDataEquals(data1, data2 signingtypes.SignatureData) bool {
 }
 
 func (s *TxConfigTestSuite) TestTxEncodeDecode() {
+	log := s.T().Log
 	_, pubkey, addr := testdata.KeyTestPubAddr()
 	feeAmount := sdk.Coins{sdk.NewInt64Coin("atom", 150)}
 	gasLimit := uint64(50000)
@@ -250,13 +251,13 @@ func (s *TxConfigTestSuite) TestTxEncodeDecode() {
 	s.Require().NoError(err)
 	tx := txBuilder.GetTx()
 
-	s.T().Log("encode transaction")
+	log("encode transaction")
 	txBytes, err := s.TxConfig.TxEncoder()(tx)
 	s.Require().NoError(err)
 	s.Require().NotNil(txBytes)
-
-	s.T().Log("decode transaction")
+	log("decode transaction", s.TxConfig)
 	tx2, err := s.TxConfig.TxDecoder()(txBytes)
+
 	s.Require().NoError(err)
 	tx3, ok := tx2.(signing.Tx)
 	s.Require().True(ok)
@@ -269,12 +270,12 @@ func (s *TxConfigTestSuite) TestTxEncodeDecode() {
 	s.Require().Equal([]signingtypes.SignatureV2{sig}, tx3Sigs)
 	s.Require().Equal([]crypto.PubKey{pubkey}, tx3.GetPubKeys())
 
-	s.T().Log("JSON encode transaction")
+	log("JSON encode transaction")
 	jsonTxBytes, err := s.TxConfig.TxJSONEncoder()(tx)
 	s.Require().NoError(err)
 	s.Require().NotNil(jsonTxBytes)
 
-	s.T().Log("JSON decode transaction")
+	log("JSON decode transaction")
 	tx2, err = s.TxConfig.TxJSONDecoder()(jsonTxBytes)
 	s.Require().NoError(err)
 	tx3, ok = tx2.(signing.Tx)
diff --git a/x/auth/tx/legacy_amino_json.go b/x/auth/tx/legacy_amino_json.go
index 886824f3a..090e3d864 100644
--- a/x/auth/tx/legacy_amino_json.go
+++ b/x/auth/tx/legacy_amino_json.go
@@ -3,11 +3,10 @@ package tx
 import (
 	"fmt"
 
-	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-	"github.com/cosmos/cosmos-sdk/x/auth/types"
-
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	signingtypes "github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
 
@@ -47,10 +46,9 @@ func (s signModeLegacyAminoJSONHandler) GetSignBytes(mode signingtypes.SignMode,
 		return nil, sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "SIGN_MODE_LEGACY_AMINO_JSON does not support protobuf extension options.")
 	}
 
-	// nolint: staticcheck
-	return types.StdSignBytes(
+	return legacytx.StdSignBytes(
 		data.ChainID, data.AccountNumber, data.Sequence, protoTx.GetTimeoutHeight(),
-		types.StdFee{Amount: protoTx.GetFee(), Gas: protoTx.GetGas()},
+		legacytx.StdFee{Amount: protoTx.GetFee(), Gas: protoTx.GetGas()},
 		tx.GetMsgs(), protoTx.GetMemo(),
 	), nil
 }
diff --git a/x/auth/tx/legacy_amino_json_test.go b/x/auth/tx/legacy_amino_json_test.go
index f7e4bb7c7..3db335286 100644
--- a/x/auth/tx/legacy_amino_json_test.go
+++ b/x/auth/tx/legacy_amino_json_test.go
@@ -9,8 +9,8 @@ import (
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	signingtypes "github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/types"
 )
 
 var (
@@ -52,7 +52,7 @@ func TestLegacyAminoJSONHandler_GetSignBytes(t *testing.T) {
 	signBz, err := handler.GetSignBytes(signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON, signingData, tx)
 	require.NoError(t, err)
 
-	expectedSignBz := types.StdSignBytes(chainId, accNum, seqNum, timeout, types.StdFee{
+	expectedSignBz := legacytx.StdSignBytes(chainId, accNum, seqNum, timeout, legacytx.StdFee{
 		Amount: coins,
 		Gas:    gas,
 	}, []sdk.Msg{msg}, memo)
diff --git a/x/auth/types/amino_signing.go b/x/auth/types/amino_signing.go
deleted file mode 100644
index 27fb7a3d7..000000000
--- a/x/auth/types/amino_signing.go
+++ /dev/null
@@ -1,44 +0,0 @@
-package types
-
-import (
-	"fmt"
-
-	sdk "github.com/cosmos/cosmos-sdk/types"
-	signingtypes "github.com/cosmos/cosmos-sdk/types/tx/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/signing"
-)
-
-// stdTxSignModeHandler is a SignModeHandler that handles SIGN_MODE_LEGACY_AMINO_JSON
-type stdTxSignModeHandler struct{}
-
-func NewStdTxSignModeHandler() signing.SignModeHandler {
-	return &stdTxSignModeHandler{}
-}
-
-var _ signing.SignModeHandler = stdTxSignModeHandler{}
-
-// DefaultMode implements SignModeHandler.DefaultMode
-func (h stdTxSignModeHandler) DefaultMode() signingtypes.SignMode {
-	return signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON
-}
-
-// Modes implements SignModeHandler.Modes
-func (stdTxSignModeHandler) Modes() []signingtypes.SignMode {
-	return []signingtypes.SignMode{signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON}
-}
-
-// DefaultMode implements SignModeHandler.GetSignBytes
-func (stdTxSignModeHandler) GetSignBytes(mode signingtypes.SignMode, data signing.SignerData, tx sdk.Tx) ([]byte, error) {
-	if mode != signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON {
-		return nil, fmt.Errorf("expected %s, got %s", signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON, mode)
-	}
-
-	stdTx, ok := tx.(StdTx)
-	if !ok {
-		return nil, fmt.Errorf("expected %T, got %T", StdTx{}, tx)
-	}
-
-	return StdSignBytes(
-		data.ChainID, data.AccountNumber, data.Sequence, stdTx.GetTimeoutHeight(), StdFee{Amount: stdTx.GetFee(), Gas: stdTx.GetGas()}, tx.GetMsgs(), stdTx.GetMemo(),
-	), nil
-}
diff --git a/x/auth/types/codec.go b/x/auth/types/codec.go
index 24ed5f32a..52b1eac4a 100644
--- a/x/auth/types/codec.go
+++ b/x/auth/types/codec.go
@@ -4,6 +4,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/codec"
 	"github.com/cosmos/cosmos-sdk/codec/types"
 	cryptocodec "github.com/cosmos/cosmos-sdk/crypto/codec"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 )
 
 // RegisterLegacyAminoCodec registers the account interfaces and concrete types on the
@@ -14,7 +15,8 @@ func RegisterLegacyAminoCodec(cdc *codec.LegacyAmino) {
 	cdc.RegisterInterface((*AccountI)(nil), nil)
 	cdc.RegisterConcrete(&BaseAccount{}, "cosmos-sdk/BaseAccount", nil)
 	cdc.RegisterConcrete(&ModuleAccount{}, "cosmos-sdk/ModuleAccount", nil)
-	cdc.RegisterConcrete(StdTx{}, "cosmos-sdk/StdTx", nil)
+
+	legacytx.RegisterLegacyAminoCodec(cdc)
 }
 
 // RegisterInterface associates protoName with AccountI interface
@@ -35,15 +37,8 @@ func RegisterInterfaces(registry types.InterfaceRegistry) {
 	)
 }
 
-// RegisterKeyTypeCodec registers an external concrete type defined in
-// another module for the internal ModuleCdc.
-func RegisterKeyTypeCodec(o interface{}, name string) {
-	amino.RegisterConcrete(o, name, nil)
-}
-
 var (
-	amino = codec.NewLegacyAmino()
-
+	amino     = codec.NewLegacyAmino()
 	ModuleCdc = codec.NewAminoCodec(amino)
 )
 
diff --git a/x/auth/types/stdtx.go b/x/auth/types/stdtx.go
deleted file mode 100644
index 214847ee9..000000000
--- a/x/auth/types/stdtx.go
+++ /dev/null
@@ -1,501 +0,0 @@
-package types
-
-import (
-	"encoding/json"
-	"fmt"
-
-	"github.com/cosmos/cosmos-sdk/types/tx/signing"
-
-	"github.com/tendermint/tendermint/crypto"
-	yaml "gopkg.in/yaml.v2"
-
-	"github.com/cosmos/cosmos-sdk/codec"
-	"github.com/cosmos/cosmos-sdk/codec/legacy"
-	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
-	kmultisig "github.com/cosmos/cosmos-sdk/crypto/keys/multisig"
-	"github.com/cosmos/cosmos-sdk/crypto/types/multisig"
-	sdk "github.com/cosmos/cosmos-sdk/types"
-	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-)
-
-// MaxGasWanted defines the max gas allowed.
-const MaxGasWanted = uint64((1 << 63) - 1)
-
-// Deprecated: StdFee includes the amount of coins paid in fees and the maximum
-// gas to be used by the transaction. The ratio yields an effective "gasprice",
-// which must be above some miminum to be accepted into the mempool.
-type StdFee struct {
-	Amount sdk.Coins `json:"amount" yaml:"amount"`
-	Gas    uint64    `json:"gas" yaml:"gas"`
-}
-
-// Deprecated: NewStdFee returns a new instance of StdFee
-func NewStdFee(gas uint64, amount sdk.Coins) StdFee {
-	return StdFee{
-		Amount: amount,
-		Gas:    gas,
-	}
-}
-
-// GetGas returns the fee's (wanted) gas.
-func (fee StdFee) GetGas() uint64 {
-	return fee.Gas
-}
-
-// GetAmount returns the fee's amount.
-func (fee StdFee) GetAmount() sdk.Coins {
-	return fee.Amount
-}
-
-// Bytes returns the encoded bytes of a StdFee.
-func (fee StdFee) Bytes() []byte {
-	if len(fee.Amount) == 0 {
-		fee.Amount = sdk.NewCoins()
-	}
-
-	bz, err := legacy.Cdc.MarshalJSON(fee)
-	if err != nil {
-		panic(err)
-	}
-
-	return bz
-}
-
-// GasPrices returns the gas prices for a StdFee.
-//
-// NOTE: The gas prices returned are not the true gas prices that were
-// originally part of the submitted transaction because the fee is computed
-// as fee = ceil(gasWanted * gasPrices).
-func (fee StdFee) GasPrices() sdk.DecCoins {
-	return sdk.NewDecCoinsFromCoins(fee.Amount...).QuoDec(sdk.NewDec(int64(fee.Gas)))
-}
-
-// Deprecated
-func NewStdSignature(pk crypto.PubKey, sig []byte) StdSignature {
-	return StdSignature{PubKey: pk, Signature: sig}
-}
-
-// GetSignature returns the raw signature bytes.
-func (ss StdSignature) GetSignature() []byte {
-	return ss.Signature
-}
-
-// GetPubKey returns the public key of a signature as a crypto.PubKey using the
-// Amino codec.
-func (ss StdSignature) GetPubKey() crypto.PubKey {
-	return ss.PubKey
-}
-
-// MarshalYAML returns the YAML representation of the signature.
-func (ss StdSignature) MarshalYAML() (interface{}, error) {
-	var (
-		bz     []byte
-		pubkey string
-		err    error
-	)
-
-	if ss.PubKey != nil {
-		pubkey, err = sdk.Bech32ifyPubKey(sdk.Bech32PubKeyTypeAccPub, ss.GetPubKey())
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	bz, err = yaml.Marshal(struct {
-		PubKey    string
-		Signature string
-	}{
-		PubKey:    pubkey,
-		Signature: fmt.Sprintf("%X", ss.Signature),
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	return string(bz), err
-}
-
-// CountSubKeys counts the total number of keys for a multi-sig public key.
-func CountSubKeys(pub crypto.PubKey) int {
-	v, ok := pub.(*kmultisig.LegacyAminoPubKey)
-	if !ok {
-		return 1
-	}
-
-	numKeys := 0
-	for _, subkey := range v.GetPubKeys() {
-		numKeys += CountSubKeys(subkey)
-	}
-
-	return numKeys
-}
-
-// ---------------------------------------------------------------------------
-// DEPRECATED
-// ---------------------------------------------------------------------------
-
-var (
-	_ sdk.Tx             = (*StdTx)(nil)
-	_ codectypes.IntoAny = (*StdTx)(nil)
-)
-
-// StdTx is the legacy transaction format for wrapping a Msg with Fee and Signatures.
-// It only works with Amino, please prefer the new protobuf Tx in types/tx.
-// NOTE: the first signature is the fee payer (Signatures must not be nil).
-type StdTx struct {
-	Msgs          []sdk.Msg      `json:"msg" yaml:"msg"`
-	Fee           StdFee         `json:"fee" yaml:"fee"`
-	Signatures    []StdSignature `json:"signatures" yaml:"signatures"`
-	Memo          string         `json:"memo" yaml:"memo"`
-	TimeoutHeight uint64         `json:"timeout_height" yaml:"timeout_height"`
-}
-
-// Deprecated
-func NewStdTx(msgs []sdk.Msg, fee StdFee, sigs []StdSignature, memo string) StdTx {
-	return StdTx{
-		Msgs:       msgs,
-		Fee:        fee,
-		Signatures: sigs,
-		Memo:       memo,
-	}
-}
-
-// GetMsgs returns the all the transaction's messages.
-func (tx StdTx) GetMsgs() []sdk.Msg { return tx.Msgs }
-
-// ValidateBasic does a simple and lightweight validation check that doesn't
-// require access to any other information.
-func (tx StdTx) ValidateBasic() error {
-	stdSigs := tx.GetSignatures()
-
-	if tx.Fee.Gas > MaxGasWanted {
-		return sdkerrors.Wrapf(
-			sdkerrors.ErrInvalidRequest,
-			"invalid gas supplied; %d > %d", tx.Fee.Gas, MaxGasWanted,
-		)
-	}
-	if tx.Fee.Amount.IsAnyNegative() {
-		return sdkerrors.Wrapf(
-			sdkerrors.ErrInsufficientFee,
-			"invalid fee provided: %s", tx.Fee.Amount,
-		)
-	}
-	if len(stdSigs) == 0 {
-		return sdkerrors.ErrNoSignatures
-	}
-	if len(stdSigs) != len(tx.GetSigners()) {
-		return sdkerrors.Wrapf(
-			sdkerrors.ErrUnauthorized,
-			"wrong number of signers; expected %d, got %d", len(tx.GetSigners()), len(stdSigs),
-		)
-	}
-
-	return nil
-}
-
-// AsAny implements IntoAny.AsAny.
-func (tx *StdTx) AsAny() *codectypes.Any {
-	return codectypes.UnsafePackAny(tx)
-}
-
-// GetSigners returns the addresses that must sign the transaction.
-// Addresses are returned in a deterministic order.
-// They are accumulated from the GetSigners method for each Msg
-// in the order they appear in tx.GetMsgs().
-// Duplicate addresses will be omitted.
-func (tx StdTx) GetSigners() []sdk.AccAddress {
-	var signers []sdk.AccAddress
-	seen := map[string]bool{}
-
-	for _, msg := range tx.GetMsgs() {
-		for _, addr := range msg.GetSigners() {
-			if !seen[addr.String()] {
-				signers = append(signers, addr)
-				seen[addr.String()] = true
-			}
-		}
-	}
-
-	return signers
-}
-
-// GetMemo returns the memo
-func (tx StdTx) GetMemo() string { return tx.Memo }
-
-// GetTimeoutHeight returns the transaction's timeout height (if set).
-func (tx StdTx) GetTimeoutHeight() uint64 {
-	return tx.TimeoutHeight
-}
-
-// GetSignatures returns the signature of signers who signed the Msg.
-// CONTRACT: Length returned is same as length of
-// pubkeys returned from MsgKeySigners, and the order
-// matches.
-// CONTRACT: If the signature is missing (ie the Msg is
-// invalid), then the corresponding signature is
-// .Empty().
-func (tx StdTx) GetSignatures() [][]byte {
-	sigs := make([][]byte, len(tx.Signatures))
-	for i, stdSig := range tx.Signatures {
-		sigs[i] = stdSig.Signature
-	}
-	return sigs
-}
-
-// GetSignaturesV2 implements SigVerifiableTx.GetSignaturesV2
-func (tx StdTx) GetSignaturesV2() ([]signing.SignatureV2, error) {
-	res := make([]signing.SignatureV2, len(tx.Signatures))
-
-	for i, sig := range tx.Signatures {
-		var err error
-		res[i], err = StdSignatureToSignatureV2(legacy.Cdc, sig)
-		if err != nil {
-			return nil, sdkerrors.Wrapf(err, "Unable to convert signature %v to V2", sig)
-		}
-	}
-
-	return res, nil
-}
-
-// GetPubkeys returns the pubkeys of signers if the pubkey is included in the signature
-// If pubkey is not included in the signature, then nil is in the slice instead
-func (tx StdTx) GetPubKeys() []crypto.PubKey {
-	pks := make([]crypto.PubKey, len(tx.Signatures))
-
-	for i, stdSig := range tx.Signatures {
-		pks[i] = stdSig.GetPubKey()
-	}
-
-	return pks
-}
-
-// GetGas returns the Gas in StdFee
-func (tx StdTx) GetGas() uint64 { return tx.Fee.Gas }
-
-// GetFee returns the FeeAmount in StdFee
-func (tx StdTx) GetFee() sdk.Coins { return tx.Fee.Amount }
-
-// FeePayer returns the address that is responsible for paying fee
-// StdTx returns the first signer as the fee payer
-// If no signers for tx, return empty address
-func (tx StdTx) FeePayer() sdk.AccAddress {
-	if tx.GetSigners() != nil {
-		return tx.GetSigners()[0]
-	}
-	return sdk.AccAddress{}
-}
-
-// StdSignDoc is replay-prevention structure.
-// It includes the result of msg.GetSignBytes(),
-// as well as the ChainID (prevent cross chain replay)
-// and the Sequence numbers for each signature (prevent
-// inchain replay and enforce tx ordering per account).
-type StdSignDoc struct {
-	AccountNumber uint64            `json:"account_number" yaml:"account_number"`
-	Sequence      uint64            `json:"sequence" yaml:"sequence"`
-	TimeoutHeight uint64            `json:"timeout_height,omitempty" yaml:"timeout_height"`
-	ChainID       string            `json:"chain_id" yaml:"chain_id"`
-	Memo          string            `json:"memo" yaml:"memo"`
-	Fee           json.RawMessage   `json:"fee" yaml:"fee"`
-	Msgs          []json.RawMessage `json:"msgs" yaml:"msgs"`
-}
-
-// StdSignBytes returns the bytes to sign for a transaction.
-func StdSignBytes(chainID string, accnum, sequence, timeout uint64, fee StdFee, msgs []sdk.Msg, memo string) []byte {
-	msgsBytes := make([]json.RawMessage, 0, len(msgs))
-	for _, msg := range msgs {
-		msgsBytes = append(msgsBytes, json.RawMessage(msg.GetSignBytes()))
-	}
-
-	bz, err := legacy.Cdc.MarshalJSON(StdSignDoc{
-		AccountNumber: accnum,
-		ChainID:       chainID,
-		Fee:           json.RawMessage(fee.Bytes()),
-		Memo:          memo,
-		Msgs:          msgsBytes,
-		Sequence:      sequence,
-		TimeoutHeight: timeout,
-	})
-	if err != nil {
-		panic(err)
-	}
-
-	return sdk.MustSortJSON(bz)
-}
-
-// Deprecated: StdSignature represents a sig
-type StdSignature struct {
-	crypto.PubKey `json:"pub_key" yaml:"pub_key"` // optional
-	Signature     []byte                          `json:"signature" yaml:"signature"`
-}
-
-// DefaultTxDecoder logic for standard transaction decoding
-func DefaultTxDecoder(cdc *codec.LegacyAmino) sdk.TxDecoder {
-	return func(txBytes []byte) (sdk.Tx, error) {
-		var tx = StdTx{}
-
-		if len(txBytes) == 0 {
-			return nil, sdkerrors.Wrap(sdkerrors.ErrTxDecode, "tx bytes are empty")
-		}
-
-		// StdTx.Msg is an interface. The concrete types
-		// are registered by MakeTxCodec
-		err := cdc.UnmarshalBinaryBare(txBytes, &tx)
-		if err != nil {
-			return nil, sdkerrors.Wrap(sdkerrors.ErrTxDecode, err.Error())
-		}
-
-		return tx, nil
-	}
-}
-
-func DefaultJSONTxDecoder(cdc *codec.LegacyAmino) sdk.TxDecoder {
-	return func(txBytes []byte) (sdk.Tx, error) {
-		var tx = StdTx{}
-
-		if len(txBytes) == 0 {
-			return nil, sdkerrors.Wrap(sdkerrors.ErrTxDecode, "tx bytes are empty")
-		}
-
-		// StdTx.Msg is an interface. The concrete types
-		// are registered by MakeTxCodec
-		err := cdc.UnmarshalJSON(txBytes, &tx)
-		if err != nil {
-			return nil, sdkerrors.Wrap(sdkerrors.ErrTxDecode, err.Error())
-		}
-
-		return tx, nil
-	}
-}
-
-// DefaultTxEncoder logic for standard transaction encoding
-func DefaultTxEncoder(cdc *codec.LegacyAmino) sdk.TxEncoder {
-	return func(tx sdk.Tx) ([]byte, error) {
-		return cdc.MarshalBinaryBare(tx)
-	}
-}
-
-var _ codectypes.UnpackInterfacesMessage = StdTx{}
-
-func (tx StdTx) UnpackInterfaces(unpacker codectypes.AnyUnpacker) error {
-	for _, m := range tx.Msgs {
-		err := codectypes.UnpackInterfaces(m, unpacker)
-		if err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-// StdSignatureToSignatureV2 converts a StdSignature to a SignatureV2
-func StdSignatureToSignatureV2(cdc *codec.LegacyAmino, sig StdSignature) (signing.SignatureV2, error) {
-	pk := sig.GetPubKey()
-	data, err := pubKeySigToSigData(cdc, pk, sig.Signature)
-	if err != nil {
-		return signing.SignatureV2{}, err
-	}
-
-	return signing.SignatureV2{
-		PubKey: pk,
-		Data:   data,
-	}, nil
-}
-
-// SignatureV2ToStdSignature converts a SignatureV2 to a StdSignature
-func SignatureV2ToStdSignature(cdc *codec.LegacyAmino, sig signing.SignatureV2) (StdSignature, error) {
-	var (
-		sigBz []byte
-		err   error
-	)
-
-	if sig.Data != nil {
-		sigBz, err = SignatureDataToAminoSignature(cdc, sig.Data)
-		if err != nil {
-			return StdSignature{}, err
-		}
-	}
-
-	return StdSignature{
-		PubKey:    sig.PubKey,
-		Signature: sigBz,
-	}, nil
-}
-
-func pubKeySigToSigData(cdc *codec.LegacyAmino, key crypto.PubKey, sig []byte) (signing.SignatureData, error) {
-	multiPK, ok := key.(multisig.PubKey)
-	if !ok {
-		return &signing.SingleSignatureData{
-			SignMode:  signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON,
-			Signature: sig,
-		}, nil
-	}
-	var multiSig multisig.AminoMultisignature
-	err := cdc.UnmarshalBinaryBare(sig, &multiSig)
-	if err != nil {
-		return nil, err
-	}
-
-	sigs := multiSig.Sigs
-	sigDatas := make([]signing.SignatureData, len(sigs))
-	pubKeys := multiPK.GetPubKeys()
-	bitArray := multiSig.BitArray
-	n := multiSig.BitArray.Count()
-	signatures := multisig.NewMultisig(n)
-	sigIdx := 0
-	for i := 0; i < n; i++ {
-		if bitArray.GetIndex(i) {
-			data, err := pubKeySigToSigData(cdc, pubKeys[i], multiSig.Sigs[sigIdx])
-			if err != nil {
-				return nil, sdkerrors.Wrapf(err, "Unable to convert Signature to SigData %d", sigIdx)
-			}
-
-			sigDatas[sigIdx] = data
-			multisig.AddSignature(signatures, data, sigIdx)
-			sigIdx++
-		}
-	}
-
-	return signatures, nil
-}
-
-// MultiSignatureDataToAminoMultisignature converts a MultiSignatureData to an AminoMultisignature.
-// Only SIGN_MODE_LEGACY_AMINO_JSON is supported.
-func MultiSignatureDataToAminoMultisignature(cdc *codec.LegacyAmino, mSig *signing.MultiSignatureData) (multisig.AminoMultisignature, error) {
-	n := len(mSig.Signatures)
-	sigs := make([][]byte, n)
-
-	for i := 0; i < n; i++ {
-		var err error
-		sigs[i], err = SignatureDataToAminoSignature(cdc, mSig.Signatures[i])
-		if err != nil {
-			return multisig.AminoMultisignature{}, sdkerrors.Wrapf(err, "Unable to convert Signature Data to signature %d", i)
-		}
-	}
-
-	return multisig.AminoMultisignature{
-		BitArray: mSig.BitArray,
-		Sigs:     sigs,
-	}, nil
-}
-
-// SignatureDataToAminoSignature converts a SignatureData to amino-encoded signature bytes.
-// Only SIGN_MODE_LEGACY_AMINO_JSON is supported.
-func SignatureDataToAminoSignature(cdc *codec.LegacyAmino, data signing.SignatureData) ([]byte, error) {
-	switch data := data.(type) {
-	case *signing.SingleSignatureData:
-		if data.SignMode != signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON {
-			return nil, fmt.Errorf("expected %s, got %s", signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON, data.SignMode)
-		}
-
-		return data.Signature, nil
-	case *signing.MultiSignatureData:
-		aminoMSig, err := MultiSignatureDataToAminoMultisignature(cdc, data)
-		if err != nil {
-			return nil, err
-		}
-
-		return cdc.MarshalBinaryBare(aminoMSig)
-	default:
-		return nil, fmt.Errorf("unexpected signature data %T", data)
-	}
-}
diff --git a/x/bank/client/rest/tx_test.go b/x/bank/client/rest/tx_test.go
index 118816c79..a11985c24 100644
--- a/x/bank/client/rest/tx_test.go
+++ b/x/bank/client/rest/tx_test.go
@@ -11,6 +11,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/rest"
 	authclient "github.com/cosmos/cosmos-sdk/x/auth/client"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
 	bankrest "github.com/cosmos/cosmos-sdk/x/bank/client/rest"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
@@ -43,25 +44,25 @@ func (s *IntegrationTestSuite) TestCoinSend() {
 	}, stdTx.GetMsgs())
 }
 
-func submitSendReq(val *network.Validator, req bankrest.SendReq) (authtypes.StdTx, error) {
+func submitSendReq(val *network.Validator, req bankrest.SendReq) (legacytx.StdTx, error) {
 	url := fmt.Sprintf("%s/bank/accounts/%s/transfers", val.APIAddress, val.Address)
 
 	// NOTE: this uses amino explicitly, don't migrate it!
 	bz, err := val.ClientCtx.LegacyAmino.MarshalJSON(req)
 	if err != nil {
-		return authtypes.StdTx{}, errors.Wrap(err, "error encoding SendReq to json")
+		return legacytx.StdTx{}, errors.Wrap(err, "error encoding SendReq to json")
 	}
 
 	res, err := rest.PostRequest(url, "application/json", bz)
 	if err != nil {
-		return authtypes.StdTx{}, err
+		return legacytx.StdTx{}, err
 	}
 
-	var tx authtypes.StdTx
+	var tx legacytx.StdTx
 	// NOTE: this uses amino explicitly, don't migrate it!
 	err = val.ClientCtx.LegacyAmino.UnmarshalJSON(res, &tx)
 	if err != nil {
-		return authtypes.StdTx{}, errors.Wrap(err, "error unmarshaling to StdTx SendReq response")
+		return legacytx.StdTx{}, errors.Wrap(err, "error unmarshaling to StdTx SendReq response")
 	}
 
 	return tx, nil