diff --git a/src/golang/cctrusted_vm/cmd/app/imr.go b/src/golang/cctrusted_vm/cmd/app/imr.go
index 985123e..f56211e 100644
--- a/src/golang/cctrusted_vm/cmd/app/imr.go
+++ b/src/golang/cctrusted_vm/cmd/app/imr.go
@@ -17,7 +17,7 @@ var imrCmd = &cobra.Command{
 		if err != nil {
 			return err
 		}
-		report, err := sdk.GetCCReport("", "", nil)
+		report, err := sdk.GetCCReport(nil, nil, nil)
 		if err != nil {
 			return err
 		}
diff --git a/src/golang/cctrusted_vm/cmd/app/report.go b/src/golang/cctrusted_vm/cmd/app/report.go
index 4f8aceb..d16d722 100644
--- a/src/golang/cctrusted_vm/cmd/app/report.go
+++ b/src/golang/cctrusted_vm/cmd/app/report.go
@@ -1,7 +1,6 @@
 package app
 
 import (
-	"encoding/base64"
 	"encoding/binary"
 	"math"
 	"math/rand"
@@ -31,14 +30,14 @@ var reportCmd = &cobra.Command{
 	},
 }
 
-func makeNonce() string {
+func makeNonce() []byte {
 	num := uint64(rand.Int63n(math.MaxInt64))
 	b := make([]byte, 8)
 	binary.LittleEndian.PutUint64(b, num)
-	return base64.StdEncoding.EncodeToString(b)
+	return b
 }
 
-func makeUserData() string {
+func makeUserData() []byte {
 	b := []byte("demo user data")
-	return base64.StdEncoding.EncodeToString(b)
+	return b
 }
diff --git a/src/golang/cctrusted_vm/cvm.go b/src/golang/cctrusted_vm/cvm.go
index 3f8731f..d9c12d3 100644
--- a/src/golang/cctrusted_vm/cvm.go
+++ b/src/golang/cctrusted_vm/cvm.go
@@ -17,7 +17,7 @@ const (
 
 type Device interface {
 	ProbeDevice() error
-	Report(nonce, userData string, extraArgs map[string]any) (evidence_api.CcReport, error)
+	Report(nonce, userData []byte, extraArgs map[string]any) (evidence_api.CcReport, error)
 	Name() string
 	CCType() evidence_api.CC_Type
 	Version() evidence_api.DeviceVersion
@@ -27,7 +27,7 @@ type GenericDevice struct {
 	Device
 }
 
-func (d *GenericDevice) Report(nonce, userData string, extraArgs map[string]any) (evidence_api.CcReport, error) {
+func (d *GenericDevice) Report(nonce, userData []byte, extraArgs map[string]any) (evidence_api.CcReport, error) {
 	var err error
 	if _, err = os.Stat(TSM_PREFIX); os.IsNotExist(err) {
 		return evidence_api.CcReport{}, errors.New("Configfs TSM is not supported in the current environment.")
@@ -36,18 +36,18 @@ func (d *GenericDevice) Report(nonce, userData string, extraArgs map[string]any)
 	// concatenate nonce and userData
 	// check if the data is base64 encoded, if yes, decode before doing hash
 	hasher := sha512.New()
-	if nonce != "" {
-		val, err := base64.StdEncoding.DecodeString(nonce)
+	if nonce != nil {
+		val, err := base64.StdEncoding.DecodeString(string(nonce))
 		if err != nil {
-			hasher.Write([]byte(nonce))
+			hasher.Write(nonce)
 		} else {
 			hasher.Write(val)
 		}
 	}
-	if userData != "" {
-		val, err := base64.StdEncoding.DecodeString(userData)
+	if userData != nil {
+		val, err := base64.StdEncoding.DecodeString(string(userData))
 		if err != nil {
-			hasher.Write([]byte(userData))
+			hasher.Write(userData)
 		} else {
 			hasher.Write(val)
 		}
diff --git a/src/golang/cctrusted_vm/sdk/sdk.go b/src/golang/cctrusted_vm/sdk/sdk.go
index be3dd14..a9219c6 100644
--- a/src/golang/cctrusted_vm/sdk/sdk.go
+++ b/src/golang/cctrusted_vm/sdk/sdk.go
@@ -37,7 +37,7 @@ func (s *SDK) DumpCCReport(reportBytes []byte) error {
 // GetCCMeasurement implements evidence_api.EvidenceAPI.
 func (s *SDK) GetCCMeasurement(index int, alg evidence_api.TCG_ALG) (evidence_api.TcgDigest, error) {
 	emptyRet := evidence_api.TcgDigest{}
-	report, err := s.GetCCReport("", "", nil)
+	report, err := s.GetCCReport(nil, nil, nil)
 	if err != nil {
 		return emptyRet, err
 	}
@@ -121,7 +121,7 @@ func (s *SDK) internelEventlog() (*evidence_api.EventLogger, error) {
 }
 
 // Report implements EvidenceAPI.
-func (s *SDK) GetCCReport(nonce, userData string, extraArgs map[string]any) (evidence_api.Report, error) {
+func (s *SDK) GetCCReport(nonce, userData []byte, extraArgs map[string]any) (evidence_api.Report, error) {
 	if s.cvm == nil {
 		return nil, errors.New("no available cvm in sdk")
 	}
diff --git a/src/golang/cctrusted_vm/tdx/device.go b/src/golang/cctrusted_vm/tdx/device.go
index 2ec6ad5..d27260f 100644
--- a/src/golang/cctrusted_vm/tdx/device.go
+++ b/src/golang/cctrusted_vm/tdx/device.go
@@ -62,7 +62,7 @@ func (t *TDXDevice) initDevice() error {
 }
 
 // Report implements cctrusted_vm.Device, get CC report
-func (t *TDXDevice) Report(nonce, userData string, extraArgs map[string]any) (evidence_api.CcReport, error) {
+func (t *TDXDevice) Report(nonce, userData []byte, extraArgs map[string]any) (evidence_api.CcReport, error) {
 	var resp evidence_api.CcReport
 	var err error
 
diff --git a/src/golang/cctrusted_vm/tdx/device_test.go b/src/golang/cctrusted_vm/tdx/device_test.go
index 664e0c1..8b7c3f3 100644
--- a/src/golang/cctrusted_vm/tdx/device_test.go
+++ b/src/golang/cctrusted_vm/tdx/device_test.go
@@ -22,8 +22,8 @@ func TestReport15(t *testing.T) {
 	fmt.Println(res)
 	assert.Equal(t, true, res)
 
-	nonce := "IXUKoBO1UM3c1wopN4sY"
-	userData := "MTIzNDU2NzgxMjM0NTY3ODEyMzQ1Njc4MTIzNDU2NzgxMjM0NTY3ODEyMzQ1Njc4"
+	nonce := []byte{"IXUKoBO1UM3c1wopN4sY"}
+	userData := []byte{"MTIzNDU2NzgxMjM0NTY3ODEyMzQ1Njc4MTIzNDU2NzgxMjM0NTY3ODEyMzQ1Njc4"}
 	tdreport, err := device.TdReport(nonce, userData)
 	assert.Nil(t, err)
 	t.Log(tdreport)
diff --git a/src/golang/cctrusted_vm/tdx/quote_handler.go b/src/golang/cctrusted_vm/tdx/quote_handler.go
index 74aa94e..5f60e31 100644
--- a/src/golang/cctrusted_vm/tdx/quote_handler.go
+++ b/src/golang/cctrusted_vm/tdx/quote_handler.go
@@ -21,7 +21,7 @@ type QuoteHandler interface {
 	Quote([tdx.TD_REPORT_LEN]byte) ([]byte, error)
 	// TdReport gets the td report of the td vm, where nonce ad userData
 	// are encoded in base64
-	TdReport(nonce, userData string) ([tdx.TD_REPORT_LEN]byte, error)
+	TdReport(nonce, userData []byte) ([tdx.TD_REPORT_LEN]byte, error)
 }
 
 var _ QuoteHandler = (*QuoteHandler15)(nil)
@@ -34,7 +34,7 @@ type QuoteHandler15 struct {
 }
 
 // TdReport implements QuoteHandler.
-func (q *QuoteHandler15) TdReport(nonce, userData string) ([tdx.TD_REPORT_LEN]byte, error) {
+func (q *QuoteHandler15) TdReport(nonce, userData []byte) ([tdx.TD_REPORT_LEN]byte, error) {
 	tdreport := [tdx.TD_REPORT_LEN]uint8{}
 	var err error
 	var file *os.File
@@ -55,18 +55,18 @@ func (q *QuoteHandler15) TdReport(nonce, userData string) ([tdx.TD_REPORT_LEN]by
 	// check if the data is base64 encoded, if yes, decode before doing hash
 	hasher := sha512.New()
 	if len(nonce) > 0 {
-		nonceDecoded, err := base64.StdEncoding.DecodeString(nonce)
+		nonceDecoded, err := base64.StdEncoding.DecodeString(string(nonce))
 		if err != nil {
-			hasher.Write([]byte(nonce))
+			hasher.Write(nonce)
 		} else {
 			hasher.Write(nonceDecoded)
 		}
 	}
 
 	if len(userData) > 0 {
-		userDataDecoded, err := base64.StdEncoding.DecodeString(userData)
+		userDataDecoded, err := base64.StdEncoding.DecodeString(string(userData))
 		if err != nil {
-			hasher.Write([]byte(userData))
+			hasher.Write(userData)
 		} else {
 			hasher.Write(userDataDecoded)
 		}