diff --git a/abci/example/orderbook/app.go b/abci/example/orderbook/app.go
index 5678bfa08..9b22929cf 100644
--- a/abci/example/orderbook/app.go
+++ b/abci/example/orderbook/app.go
@@ -7,6 +7,7 @@ import (
 	dbm "github.com/tendermint/tm-db"
 
 	"github.com/tendermint/tendermint/abci/types"
+	"github.com/tendermint/tendermint/crypto/ed25519"
 )
 
 var _ types.Application = (*StateMachine)(nil)
@@ -21,6 +22,7 @@ const (
 	ErrValidateBasic
 	ErrNoAccount
 	ErrNoPair
+	ErrInvalidSignature
 )
 
 type StateMachine struct {
@@ -83,7 +85,8 @@ func (sm *StateMachine) CheckTx(req types.RequestCheckTx) types.ResponseCheckTx
 		}
 
 		// check if account exists
-		if _, ok := sm.accounts[m.MsgBid.BidOrder.OwnerId]; !ok {
+		account, ok := sm.accounts[m.MsgBid.BidOrder.OwnerId]
+		if !ok {
 			return types.ResponseCheckTx{Code: ErrNoAccount}
 		}
 
@@ -92,6 +95,11 @@ func (sm *StateMachine) CheckTx(req types.RequestCheckTx) types.ResponseCheckTx
 			return types.ResponseCheckTx{Code: ErrNoPair}
 		}
 
+		// verify signature
+		if !m.MsgBid.BidOrder.ValidateSignature(ed25519.PubKey(account.PublicKey), m.MsgBid.Pair) {
+			return types.ResponseCheckTx{Code: ErrInvalidSignature}
+		}
+
 	case *Msg_MsgAsk:
 
 		if err := m.MsgAsk.ValidateBasic(); err != nil {
@@ -99,7 +107,7 @@ func (sm *StateMachine) CheckTx(req types.RequestCheckTx) types.ResponseCheckTx
 		}
 
 		// check if account exists
-		_, ok := sm.accounts[m.MsgAsk.AskOrder.OwnerId]
+		account, ok := sm.accounts[m.MsgAsk.AskOrder.OwnerId]
 		if !ok {
 			return types.ResponseCheckTx{Code: ErrNoAccount}
 		}
@@ -109,6 +117,11 @@ func (sm *StateMachine) CheckTx(req types.RequestCheckTx) types.ResponseCheckTx
 			return types.ResponseCheckTx{Code: ErrNoPair}
 		}
 
+		// verify signature
+		if !m.MsgAsk.AskOrder.ValidateSignature(ed25519.PubKey(account.PublicKey), m.MsgAsk.Pair) {
+			return types.ResponseCheckTx{Code: ErrInvalidSignature}
+		}
+
 	default:
 		return types.ResponseCheckTx{Code: ErrUnknownMessage} // unknown message type
 	}
@@ -267,8 +280,6 @@ func (sm *StateMachine) ProcessProposal(req types.RequestProcessProposal) types.
 				return rejectProposal()
 			}
 
-			// TODO: verify the signature
-
 		case *Msg_MsgAsk, *Msg_MsgBid: // MsgAsk and MsgBid are not allowed individually - they need to be matched as a TradeSet
 			return rejectProposal()
 
@@ -282,8 +293,6 @@ func (sm *StateMachine) ProcessProposal(req types.RequestProcessProposal) types.
 				return rejectProposal()
 			}
 
-			// TODO: verify the signature
-
 		case *Msg_MsgTradeSet:
 			// for each matched order
 			// check the accounts exist, that the signatures are valid and that they have the available funds to make the swap
@@ -297,14 +306,20 @@ func (sm *StateMachine) ProcessProposal(req types.RequestProcessProposal) types.
 			}
 
 			for _, order := range m.MsgTradeSet.TradeSet.MatchedOrders {
+				// validate matched order i.e. users have funds
 				if !sm.isMatchedOrderValid(order, m.MsgTradeSet.TradeSet.Pair) {
 					return rejectProposal()
 				}
 
-				// bidOwner := sm.accounts[order.OrderBid.OwnerId]
-				// askOwner := sm.accounts[order.OrderAsk.OwnerId]
-
-				// ed25519.Verify(bidOwner.PublicKey, )
+				// verify signatures
+				bidOwner := sm.accounts[order.OrderBid.OwnerId]
+				askOwner := sm.accounts[order.OrderAsk.OwnerId]
+				if !order.OrderAsk.ValidateSignature(ed25519.PubKey(askOwner.PublicKey), m.MsgTradeSet.TradeSet.Pair) {
+					return rejectProposal()
+				}
+				if !order.OrderBid.ValidateSignature(ed25519.PubKey(bidOwner.PublicKey), m.MsgTradeSet.TradeSet.Pair) {
+					return rejectProposal()
+				}
 			}
 
 		default:
diff --git a/abci/example/orderbook/app_test.go b/abci/example/orderbook/app_test.go
index 4e2dd4ba2..83017dd68 100644
--- a/abci/example/orderbook/app_test.go
+++ b/abci/example/orderbook/app_test.go
@@ -27,7 +27,7 @@ func TestCheckTx(t *testing.T) {
 		{
 			name: "test msg ask",
 			msg: &orderbook.Msg{Sum: &orderbook.Msg_MsgAsk{MsgAsk: &orderbook.MsgAsk{
-				Pair: testPair,
+				Pair: &testPair,
 				AskOrder: &orderbook.OrderAsk{
 					Quantity:  10,
 					AskPrice:  1,
@@ -40,21 +40,21 @@ func TestCheckTx(t *testing.T) {
 		{
 			name: "test msg bid",
 			msg: &orderbook.Msg{Sum: &orderbook.Msg_MsgBid{MsgBid: &orderbook.MsgBid{
-				Pair: testPair, 
-				OrderBid: &orderbook.OrderBid{
+				Pair: &testPair,
+				BidOrder: &orderbook.OrderBid{
 					MaxQuantity: 15,
 					MaxPrice:    5,
 					OwnerId:     1,
 					Signature:   []byte("signature"),
 				},
-			}},
+			}}},
 			responseCode: orderbook.StatusOK,
 		},
 		{
 			name: "test msg register pair",
 			msg: &orderbook.Msg{Sum: &orderbook.Msg_MsgRegisterPair{MsgRegisterPair: &orderbook.MsgRegisterPair{
-				Pair: testPair,
-			}},
+				Pair: &testPair,
+			}}},
 			responseCode: orderbook.StatusOK,
 		},
 	}