diff --git a/x/bank/simulation/msgs.go b/x/bank/simulation/msgs.go
index 553d000db4..3a72488757 100644
--- a/x/bank/simulation/msgs.go
+++ b/x/bank/simulation/msgs.go
@@ -22,15 +22,15 @@ import (
 // accounts already exist.
 func TestAndRunSingleInputMsgSend(mapper auth.AccountMapper) simulation.TestAndRunTx {
 	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, err sdk.Error) {
-		fromKey := keys[r.Intn(len(keys))]
+		fromKey := simulation.RandomKey(r, keys)
 		fromAddr := sdk.AccAddress(fromKey.PubKey().Address())
-		toKey := keys[r.Intn(len(keys))]
+		toKey := simulation.RandomKey(r, keys)
 		// Disallow sending money to yourself
 		for {
 			if !fromKey.Equals(toKey) {
 				break
 			}
-			toKey = keys[r.Intn(len(keys))]
+			toKey = simulation.RandomKey(r, keys)
 		}
 		toAddr := sdk.AccAddress(toKey.PubKey().Address())
 		initFromCoins := mapper.GetAccount(ctx, fromAddr).GetCoins()
diff --git a/x/mock/simulation/util.go b/x/mock/simulation/util.go
index 8fdf5021e0..14227a1aef 100644
--- a/x/mock/simulation/util.go
+++ b/x/mock/simulation/util.go
@@ -3,6 +3,10 @@ package simulation
 import (
 	"fmt"
 	"math/rand"
+
+	crypto "github.com/tendermint/tendermint/crypto"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
 // shamelessly copied from https://stackoverflow.com/questions/22892120/how-to-generate-a-random-string-of-a-fixed-length-in-golang#31832326
@@ -38,3 +42,15 @@ func DisplayEvents(events map[string]uint) {
 	// TODO
 	fmt.Printf("Events: %v\n", events)
 }
+
+// Pick a random key from an array
+func RandomKey(r *rand.Rand, keys []crypto.PrivKey) crypto.PrivKey {
+	return keys[r.Intn(
+		len(keys),
+	)]
+}
+
+// Generate a random amount
+func RandomAmount(r *rand.Rand, max sdk.Int) sdk.Int {
+	return sdk.NewInt(int64(r.Intn(int(max.Int64()))))
+}
diff --git a/x/stake/simulation/msgs.go b/x/stake/simulation/msgs.go
index 41bda5dd6f..87324eed72 100644
--- a/x/stake/simulation/msgs.go
+++ b/x/stake/simulation/msgs.go
@@ -24,12 +24,12 @@ func SimulateMsgCreateValidator(m auth.AccountMapper, k stake.Keeper) simulation
 		description := stake.Description{
 			Moniker: simulation.RandStringOfLength(r, 10),
 		}
-		key := keys[r.Intn(len(keys))]
+		key := simulation.RandomKey(r, keys)
 		pubkey := key.PubKey()
 		address := sdk.AccAddress(pubkey.Address())
 		amount := m.GetAccount(ctx, address).GetCoins().AmountOf(denom)
 		if amount.GT(sdk.ZeroInt()) {
-			amount = sdk.NewInt(int64(r.Intn(int(amount.Int64()))))
+			amount = simulation.RandomAmount(r, amount)
 		}
 		if amount.Equal(sdk.ZeroInt()) {
 			return "no-operation", nil
@@ -63,7 +63,7 @@ func SimulateMsgEditValidator(k stake.Keeper) simulation.TestAndRunTx {
 			Website:  simulation.RandStringOfLength(r, 10),
 			Details:  simulation.RandStringOfLength(r, 10),
 		}
-		key := keys[r.Intn(len(keys))]
+		key := simulation.RandomKey(r, keys)
 		pubkey := key.PubKey()
 		address := sdk.AccAddress(pubkey.Address())
 		msg := stake.MsgEditValidator{
@@ -86,13 +86,13 @@ func SimulateMsgEditValidator(k stake.Keeper) simulation.TestAndRunTx {
 func SimulateMsgDelegate(m auth.AccountMapper, k stake.Keeper) simulation.TestAndRunTx {
 	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, err sdk.Error) {
 		denom := k.GetParams(ctx).BondDenom
-		validatorKey := keys[r.Intn(len(keys))]
+		validatorKey := simulation.RandomKey(r, keys)
 		validatorAddress := sdk.AccAddress(validatorKey.PubKey().Address())
-		delegatorKey := keys[r.Intn(len(keys))]
+		delegatorKey := simulation.RandomKey(r, keys)
 		delegatorAddress := sdk.AccAddress(delegatorKey.PubKey().Address())
 		amount := m.GetAccount(ctx, delegatorAddress).GetCoins().AmountOf(denom)
 		if amount.GT(sdk.ZeroInt()) {
-			amount = sdk.NewInt(int64(r.Intn(int(amount.Int64()))))
+			amount = simulation.RandomAmount(r, amount)
 		}
 		if amount.Equal(sdk.ZeroInt()) {
 			return "no-operation", nil
@@ -118,13 +118,13 @@ func SimulateMsgDelegate(m auth.AccountMapper, k stake.Keeper) simulation.TestAn
 func SimulateMsgBeginUnbonding(m auth.AccountMapper, k stake.Keeper) simulation.TestAndRunTx {
 	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, err sdk.Error) {
 		denom := k.GetParams(ctx).BondDenom
-		validatorKey := keys[r.Intn(len(keys))]
+		validatorKey := simulation.RandomKey(r, keys)
 		validatorAddress := sdk.AccAddress(validatorKey.PubKey().Address())
-		delegatorKey := keys[r.Intn(len(keys))]
+		delegatorKey := simulation.RandomKey(r, keys)
 		delegatorAddress := sdk.AccAddress(delegatorKey.PubKey().Address())
 		amount := m.GetAccount(ctx, delegatorAddress).GetCoins().AmountOf(denom)
 		if amount.GT(sdk.ZeroInt()) {
-			amount = sdk.NewInt(int64(r.Intn(int(amount.Int64()))))
+			amount = simulation.RandomAmount(r, amount)
 		}
 		if amount.Equal(sdk.ZeroInt()) {
 			return "no-operation", nil
@@ -149,9 +149,9 @@ func SimulateMsgBeginUnbonding(m auth.AccountMapper, k stake.Keeper) simulation.
 // SimulateMsgCompleteUnbonding
 func SimulateMsgCompleteUnbonding(k stake.Keeper) simulation.TestAndRunTx {
 	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, err sdk.Error) {
-		validatorKey := keys[r.Intn(len(keys))]
+		validatorKey := simulation.RandomKey(r, keys)
 		validatorAddress := sdk.AccAddress(validatorKey.PubKey().Address())
-		delegatorKey := keys[r.Intn(len(keys))]
+		delegatorKey := simulation.RandomKey(r, keys)
 		delegatorAddress := sdk.AccAddress(delegatorKey.PubKey().Address())
 		msg := stake.MsgCompleteUnbonding{
 			DelegatorAddr: delegatorAddress,
@@ -173,16 +173,16 @@ func SimulateMsgCompleteUnbonding(k stake.Keeper) simulation.TestAndRunTx {
 func SimulateMsgBeginRedelegate(m auth.AccountMapper, k stake.Keeper) simulation.TestAndRunTx {
 	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, err sdk.Error) {
 		denom := k.GetParams(ctx).BondDenom
-		sourceValidatorKey := keys[r.Intn(len(keys))]
+		sourceValidatorKey := simulation.RandomKey(r, keys)
 		sourceValidatorAddress := sdk.AccAddress(sourceValidatorKey.PubKey().Address())
-		destValidatorKey := keys[r.Intn(len(keys))]
+		destValidatorKey := simulation.RandomKey(r, keys)
 		destValidatorAddress := sdk.AccAddress(destValidatorKey.PubKey().Address())
-		delegatorKey := keys[r.Intn(len(keys))]
+		delegatorKey := simulation.RandomKey(r, keys)
 		delegatorAddress := sdk.AccAddress(delegatorKey.PubKey().Address())
 		// TODO
 		amount := m.GetAccount(ctx, delegatorAddress).GetCoins().AmountOf(denom)
 		if amount.GT(sdk.ZeroInt()) {
-			amount = sdk.NewInt(int64(r.Intn(int(amount.Int64()))))
+			amount = simulation.RandomAmount(r, amount)
 		}
 		if amount.Equal(sdk.ZeroInt()) {
 			return "no-operation", nil
@@ -208,11 +208,11 @@ func SimulateMsgBeginRedelegate(m auth.AccountMapper, k stake.Keeper) simulation
 // SimulateMsgCompleteRedelegate
 func SimulateMsgCompleteRedelegate(k stake.Keeper) simulation.TestAndRunTx {
 	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, err sdk.Error) {
-		validatorSrcKey := keys[r.Intn(len(keys))]
+		validatorSrcKey := simulation.RandomKey(r, keys)
 		validatorSrcAddress := sdk.AccAddress(validatorSrcKey.PubKey().Address())
-		validatorDstKey := keys[r.Intn(len(keys))]
+		validatorDstKey := simulation.RandomKey(r, keys)
 		validatorDstAddress := sdk.AccAddress(validatorDstKey.PubKey().Address())
-		delegatorKey := keys[r.Intn(len(keys))]
+		delegatorKey := simulation.RandomKey(r, keys)
 		delegatorAddress := sdk.AccAddress(delegatorKey.PubKey().Address())
 		msg := stake.MsgCompleteRedelegate{
 			DelegatorAddr:    delegatorAddress,
@@ -240,7 +240,7 @@ func Setup(mapp *mock.App, k stake.Keeper) simulation.RandSetup {
 		denom := params.BondDenom
 		loose := sdk.ZeroInt()
 		mapp.AccountMapper.IterateAccounts(ctx, func(acc auth.Account) bool {
-			balance := sdk.NewInt(int64(r.Intn(1000000)))
+			balance := simulation.RandomAmount(r, sdk.NewInt(1000000))
 			acc.SetCoins(acc.GetCoins().Plus(sdk.Coins{sdk.NewIntCoin(denom, balance)}))
 			mapp.AccountMapper.SetAccount(ctx, acc)
 			loose = loose.Add(balance)