diff --git a/scalabot-app/src/main/java/net/lamgc/scalabot/util/ByteUtils.java b/scalabot-app/src/main/java/net/lamgc/scalabot/util/ByteUtils.java
index ed529e4..3888fdf 100644
--- a/scalabot-app/src/main/java/net/lamgc/scalabot/util/ByteUtils.java
+++ b/scalabot-app/src/main/java/net/lamgc/scalabot/util/ByteUtils.java
@@ -8,7 +8,8 @@ final class ByteUtils {
     public static String bytesToHexString(byte[] bytes) {
         StringBuilder builder = new StringBuilder();
         for (byte aByte : bytes) {
-            builder.append(Integer.toHexString(aByte));
+            String hexBit = Integer.toHexString(aByte & 0xFF);
+            builder.append(hexBit.length() == 1 ? "0" + hexBit : hexBit);
         }
         return builder.toString();
     }
diff --git a/scalabot-app/src/main/kotlin/BotDBMaker.kt b/scalabot-app/src/main/kotlin/BotDBMaker.kt
index 5bcdefb..37a3f8d 100644
--- a/scalabot-app/src/main/kotlin/BotDBMaker.kt
+++ b/scalabot-app/src/main/kotlin/BotDBMaker.kt
@@ -8,10 +8,8 @@ import java.nio.charset.StandardCharsets
 import java.security.MessageDigest
 
 internal object BotDBMaker {
-
-    private val digest: MessageDigest = MessageDigest.getInstance("SHA-256")
-
     fun getBotMaker(botAccount: BotAccount): DBContext {
+        val digest: MessageDigest = MessageDigest.getInstance("SHA-256")
         val digestBytes = digest.digest(botAccount.token.toByteArray(StandardCharsets.UTF_8))
         val dbPath = AppPaths.DATA_DB.path + "${digestBytes.toHaxString()}.db"
         val db = DBMaker.fileDB(dbPath)