diff --git a/relay/lcp.go b/relay/lcp.go
index df10c40..a126a77 100644
--- a/relay/lcp.go
+++ b/relay/lcp.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"log"
 	"os"
 	"path/filepath"
@@ -13,13 +14,14 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	clienttypes "github.com/cosmos/ibc-go/v7/modules/core/02-client/types"
 	ibcexported "github.com/cosmos/ibc-go/v7/modules/core/exported"
+	mapset "github.com/deckarep/golang-set/v2"
+	"github.com/hyperledger-labs/yui-relayer/core"
+	oias "github.com/oasisprotocol/oasis-core/go/common/sgx/ias"
+
 	lcptypes "github.com/datachainlab/lcp-go/light-clients/lcp/types"
 	"github.com/datachainlab/lcp-go/relay/elc"
 	"github.com/datachainlab/lcp-go/relay/enclave"
 	"github.com/datachainlab/lcp-go/sgx/ias"
-	mapset "github.com/deckarep/golang-set/v2"
-	"github.com/hyperledger-labs/yui-relayer/core"
-	oias "github.com/oasisprotocol/oasis-core/go/common/sgx/ias"
 )
 
 const lastEnclaveKeyInfoFile = "last_eki"
@@ -46,26 +48,35 @@ func (pr *Prover) loadLastEnclaveKey(ctx context.Context) (*enclave.EnclaveKeyIn
 }
 
 func (pr *Prover) saveLastEnclaveKey(ctx context.Context, eki *enclave.EnclaveKeyInfo) error {
-	path, err := pr.lastEnclaveKeyInfoFilePath()
+	src, err := os.CreateTemp(os.TempDir(), lastEnclaveKeyInfoFile)
 	if err != nil {
 		return err
 	}
-	f, err := os.CreateTemp(os.TempDir(), lastEnclaveKeyInfoFile)
+	defer src.Close()
+
+	bz, err := json.Marshal(eki)
 	if err != nil {
 		return err
 	}
-	defer f.Close()
 
-	bz, err := json.Marshal(eki)
+	if err = os.WriteFile(src.Name(), bz, 0600); err != nil {
+		return err
+	}
+
+	path, err := pr.lastEnclaveKeyInfoFilePath()
 	if err != nil {
 		return err
 	}
-	if _, err := f.Write(bz); err != nil {
+	dst, err := os.Create(path)
+	if err != nil {
 		return err
 	}
-	if err := os.Rename(f.Name(), path); err != nil {
+	defer dst.Close()
+
+	if _, err = io.Copy(dst, src); err != nil {
 		return err
 	}
+
 	return nil
 }
 
diff --git a/simapp/go.mod b/simapp/go.mod
index 2305e05..b739545 100644
--- a/simapp/go.mod
+++ b/simapp/go.mod
@@ -127,8 +127,8 @@ require (
 	github.com/petermattis/goid v0.0.0-20230317030725-371a4b8eda08 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/prometheus/client_golang v1.14.0 // indirect
-	github.com/prometheus/client_model v0.3.0 // indirect
+	github.com/prometheus/client_golang v1.15.1 // indirect
+	github.com/prometheus/client_model v0.4.0 // indirect
 	github.com/prometheus/common v0.42.0 // indirect
 	github.com/prometheus/procfs v0.9.0 // indirect
 	github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475 // indirect
diff --git a/simapp/go.sum b/simapp/go.sum
index 760d703..0da811c 100644
--- a/simapp/go.sum
+++ b/simapp/go.sum
@@ -826,6 +826,7 @@ github.com/prometheus/client_golang v1.4.0/go.mod h1:e9GMxYsXl05ICDXkRhurwBS4Q3O
 github.com/prometheus/client_golang v1.7.1/go.mod h1:PY5Wy2awLA44sXw4AOSfFBetzPP4j5+D6mVACh+pe2M=
 github.com/prometheus/client_golang v1.14.0 h1:nJdhIvne2eSX/XRAFV9PcvFFRbrjbcTUj0VP62TMhnw=
 github.com/prometheus/client_golang v1.14.0/go.mod h1:8vpkKitgIVNcqrRBWh1C4TIUQgYNtG/XQE4E/Zae36Y=
+github.com/prometheus/client_golang v1.15.1/go.mod h1:e9yaBhRPU2pPNsZwE+JdQl0KEt1N9XgF6zxWmaC0xOk=
 github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
 github.com/prometheus/client_model v0.0.0-20190115171406-56726106282f/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
 github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
@@ -834,6 +835,7 @@ github.com/prometheus/client_model v0.1.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6T
 github.com/prometheus/client_model v0.2.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/prometheus/client_model v0.3.0 h1:UBgGFHqYdG/TPFD1B1ogZywDqEkwp3fBMvqdiQ7Xew4=
 github.com/prometheus/client_model v0.3.0/go.mod h1:LDGWKZIo7rky3hgvBe+caln+Dr3dPggB5dvjtD7w9+w=
+github.com/prometheus/client_model v0.4.0/go.mod h1:oMQmHW1/JoDwqLtg57MGgP/Fb1CJEYF2imWWhWtMkYU=
 github.com/prometheus/common v0.2.0/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.7.0/go.mod h1:DjGbpBbp5NYNiECxcL/VnbXCCaQpKd3tt26CguLLsqA=