diff --git a/provers/mock/prover.go b/provers/mock/prover.go
index c5aecac8..3be2ebfd 100644
--- a/provers/mock/prover.go
+++ b/provers/mock/prover.go
@@ -3,8 +3,8 @@ package mock
 import (
 	"context"
 	"crypto/sha256"
+	"encoding/binary"
 	fmt "fmt"
-	"math/big"
 	"time"
 
 	"github.com/cosmos/cosmos-sdk/codec"
@@ -126,19 +126,16 @@ func makeProof(height exported.Height, path string, bz []byte) []byte {
 	revisionNumber := height.GetRevisionNumber()
 	revisionHeight := height.GetRevisionHeight()
 
-	heightBig := new(big.Int)
-	revisionNumberBig := new(big.Int).SetUint64(revisionNumber)
-	revisionNumberBig = revisionNumberBig.Lsh(revisionNumberBig, 64)
-	revisionHeightBig := new(big.Int).SetUint64(revisionHeight)
-	heightBig.Or(revisionNumberBig, revisionHeightBig)
-	hashHeight := sha256.Sum256(heightBig.Bytes())
+	heightBuf := make([]byte, 16)
+	binary.LittleEndian.PutUint64(heightBuf[:8], revisionHeight)
+	binary.LittleEndian.PutUint64(heightBuf[8:], revisionNumber)
 
 	hashPrefix := sha256.Sum256(core.DefaultChainPrefix.Bytes())
 	hashPath := sha256.Sum256([]byte(path))
 	hashValue := sha256.Sum256([]byte(bz))
 
 	var combined []byte
-	combined = append(combined, hashHeight[:]...)
+	combined = append(combined, heightBuf...)
 	combined = append(combined, hashPrefix[:]...)
 	combined = append(combined, hashPath[:]...)
 	combined = append(combined, hashValue[:]...)
diff --git a/tests/chains/tendermint/go.mod b/tests/chains/tendermint/go.mod
index bdfd19d0..6c724630 100644
--- a/tests/chains/tendermint/go.mod
+++ b/tests/chains/tendermint/go.mod
@@ -168,6 +168,6 @@ require (
 replace (
 	// https://github.com/cosmos/cosmos-sdk/blob/v0.47.3/go.mod#L171-L182
 	github.com/99designs/keyring => github.com/cosmos/keyring v1.2.0
-	github.com/datachainlab/ibc-mock-client => github.com/dongrie/ibc-mock-client v0.3.3-0.20231213015729-29b70e76baf2
+	github.com/datachainlab/ibc-mock-client => github.com/dongrie/ibc-mock-client v0.3.3-0.20231221102347-9000a7df65b4
 	github.com/syndtr/goleveldb => github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7
 )
diff --git a/tests/chains/tendermint/go.sum b/tests/chains/tendermint/go.sum
index 9a164fb1..3f25ca68 100644
--- a/tests/chains/tendermint/go.sum
+++ b/tests/chains/tendermint/go.sum
@@ -370,8 +370,8 @@ github.com/dgryski/go-farm v0.0.0-20200201041132-a6ae2369ad13 h1:fAjc9m62+UWV/WA
 github.com/dgryski/go-farm v0.0.0-20200201041132-a6ae2369ad13/go.mod h1:SqUrOPUnsFjfmXRMNPybcSiG0BgUW2AuFH8PAnS2iTw=
 github.com/docker/go-connections v0.4.0 h1:El9xVISelRB7BuFusrZozjnkIM5YnzCViNKohAFqRJQ=
 github.com/docker/go-units v0.5.0 h1:69rxXcBk27SvSaaxTtLh/8llcHD8vYHT7WSdRZ/jvr4=
-github.com/dongrie/ibc-mock-client v0.3.3-0.20231213015729-29b70e76baf2 h1:wuqyTnekH+pfNr+0Nrfq6PJgvllBbr7brabygF7oLlM=
-github.com/dongrie/ibc-mock-client v0.3.3-0.20231213015729-29b70e76baf2/go.mod h1:FfqyF+VJKp8jlIG21lTNJJIp8RCaxSrx6vjhNkfwgBM=
+github.com/dongrie/ibc-mock-client v0.3.3-0.20231221102347-9000a7df65b4 h1:6Ons8oPPMxqjPpcIRan7duWpyjVBnOR6S2u0iiTIBWk=
+github.com/dongrie/ibc-mock-client v0.3.3-0.20231221102347-9000a7df65b4/go.mod h1:FfqyF+VJKp8jlIG21lTNJJIp8RCaxSrx6vjhNkfwgBM=
 github.com/dustin/go-humanize v0.0.0-20171111073723-bb3d318650d4/go.mod h1:HtrtbFcZ19U5GC7JDqmcUSB87Iq5E25KnS6fMYU6eOk=
 github.com/dustin/go-humanize v1.0.0/go.mod h1:HtrtbFcZ19U5GC7JDqmcUSB87Iq5E25KnS6fMYU6eOk=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=