diff --git a/Launcher/source/hasher/HashedFile.java b/Launcher/source/hasher/HashedFile.java
index 306cbd1..0becfe0 100644
--- a/Launcher/source/hasher/HashedFile.java
+++ b/Launcher/source/hasher/HashedFile.java
@@ -22,7 +22,7 @@
     @LauncherAPI
     public HashedFile(long size, byte[] digest) {
         this.size = VerifyHelper.verifyLong(size, VerifyHelper.L_NOT_NEGATIVE, "Illegal size: " + size);
-        this.digest = DIGEST_ALGO.verify(digest).clone();
+        this.digest = digest == null ? null : DIGEST_ALGO.verify(digest).clone();
     }
 
     @LauncherAPI
diff --git a/Launcher/source/helper/VerifyHelper.java b/Launcher/source/helper/VerifyHelper.java
index aa2a2f0..5e06a7a 100644
--- a/Launcher/source/helper/VerifyHelper.java
+++ b/Launcher/source/helper/VerifyHelper.java
@@ -41,6 +41,7 @@
         return USERNAME_PATTERN.matcher(username).matches();
     }
 
+    @LauncherAPI
     public static <K, V> void putIfAbsent(Map<K, V> map, K key, V value, String error) {
         verify(map.putIfAbsent(key, value), Objects::isNull, error);
     }
diff --git a/Launcher/source/request/update/UpdateRequest.java b/Launcher/source/request/update/UpdateRequest.java
index 3741fe1..5d5f06a 100644
--- a/Launcher/source/request/update/UpdateRequest.java
+++ b/Launcher/source/request/update/UpdateRequest.java
@@ -180,7 +180,7 @@
         updateState(filePath, 0L, hFile.size);
 
         // Start file update
-        MessageDigest digest = SecurityHelper.newDigest(DigestAlgorithm.MD5);
+        MessageDigest digest = this.digest ? SecurityHelper.newDigest(DigestAlgorithm.MD5) : null;
         try (OutputStream fileOutput = IOHelper.newOutput(file)) {
             long downloaded = 0L;
 
@@ -194,8 +194,10 @@
                 }
 
                 // Update file
-                digest.update(bytes, 0, length);
                 fileOutput.write(bytes, 0, length);
+                if (digest != null) {
+                    digest.update(bytes, 0, length);
+                }
 
                 // Update state
                 downloaded += length;
@@ -205,9 +207,11 @@
         }
 
         // Verify digest
-        byte[] digestBytes = digest.digest();
-        if (!hFile.isSameDigest(digestBytes)) {
-            throw new SecurityException(String.format("File digest mismatch: '%s'", filePath));
+        if (digest != null) {
+            byte[] digestBytes = digest.digest();
+            if (!hFile.isSameDigest(digestBytes)) {
+                throw new SecurityException(String.format("File digest mismatch: '%s'", filePath));
+            }
         }
     }