diff --git a/ntlm/ntlmv2.go b/ntlm/ntlmv2.go
index 171a9bb..9e6e417 100644
--- a/ntlm/ntlmv2.go
+++ b/ntlm/ntlmv2.go
@@ -6,6 +6,7 @@ import (
 	"bytes"
 	rc4P "crypto/rc4"
 	"encoding/binary"
+	"encoding/hex"
 	"fmt"
 	"log"
 	"os/exec"
@@ -245,11 +246,14 @@ func (n *V2ServerSession) ProcessAuthenticateMessage(am *AuthenticateMessage) (e
 		return err
 	}
 
-	log.Printf("DEBUG: challenge Server: %s\n", string(n.serverChallenge))
-	log.Printf("DEBUG: ntChallengeResponse: %s\n", string(n.ntChallengeResponse))
+	hexServerChallenge := hex.EncodeToString(n.serverChallenge)
+	hexClientChallenge := hex.EncodeToString(n.clientChallenge)
+
+	log.Printf("DEBUG: challenge Server: %v\n", hexServerChallenge)
+	log.Printf("DEBUG: ntChallengeResponse: %v\n", hexClientChallenge))
 
 	// Execute ntlm_auth to check user auth
-	cmd := exec.Command("/usr/local/bin/ntlm_auth", "--domain="+n.userDomain, "--username="+n.user, "--challenge="+string(n.serverChallenge), "--nt-response="+string(n.ntChallengeResponse))
+	cmd := exec.Command("/usr/local/bin/ntlm_auth", "--domain="+n.userDomain, "--username="+n.user, "--challenge="+hexServerChallenge, "--nt-response="+hexClientChallenge)
 	output, err := cmd.CombinedOutput()
 	if err != nil {
 		fmt.Printf("Failed to execute command: %s\n", err)