diff --git a/src/main/java/com/reandroid/archive2/block/ApkSignatureBlock.java b/src/main/java/com/reandroid/archive2/block/ApkSignatureBlock.java
index 4220113..4c2c289 100644
--- a/src/main/java/com/reandroid/archive2/block/ApkSignatureBlock.java
+++ b/src/main/java/com/reandroid/archive2/block/ApkSignatureBlock.java
@@ -148,13 +148,7 @@ public class ApkSignatureBlock extends LengthPrefixedList<SignatureInfo>
     }
     @Override
     public int compare(SignatureInfo info1, SignatureInfo info2) {
-        if(SignatureId.PADDING.equals(info1.getId())){
-            return 0;
-        }
-        if(SignatureId.PADDING.equals(info2.getId())){
-            return 1;
-        }
-        return 0;
+        return info1.getId().compareTo(info2.getId());
     }
 
     public static final String FILE_EXT = ".sig";
diff --git a/src/main/java/com/reandroid/archive2/block/SignatureId.java b/src/main/java/com/reandroid/archive2/block/SignatureId.java
index 501fc04..47a9918 100644
--- a/src/main/java/com/reandroid/archive2/block/SignatureId.java
+++ b/src/main/java/com/reandroid/archive2/block/SignatureId.java
@@ -19,13 +19,15 @@ import com.reandroid.arsc.decoder.ValueDecoder;
 
 import java.util.Objects;
 
-public class SignatureId {
+public class SignatureId implements Comparable<SignatureId>{
     private final String name;
     private final int id;
+    private final int sort;
 
-    private SignatureId(String name, int id) {
+    private SignatureId(String name, int id, int sort) {
         this.name = name;
         this.id = id;
+        this.sort = sort;
     }
     public String name() {
         return name;
@@ -51,6 +53,10 @@ public class SignatureId {
         return id == that.id;
     }
     @Override
+    public int compareTo(SignatureId signatureId) {
+        return Integer.compare(sort, signatureId.sort);
+    }
+    @Override
     public int hashCode() {
         return Objects.hash(id);
     }
@@ -76,7 +82,7 @@ public class SignatureId {
             }
         }
         if (ValueDecoder.isHex(name)) {
-            return new SignatureId(null, ValueDecoder.parseHex(name));
+            return new SignatureId(null, ValueDecoder.parseHex(name), 99);
         }
         return null;
     }
@@ -86,20 +92,20 @@ public class SignatureId {
                 return signatureId;
             }
         }
-        return new SignatureId(null, id);
+        return new SignatureId(null, id, 99);
     }
 
     public static SignatureId[] values() {
         return VALUES.clone();
     }
 
-    public static final SignatureId V2 = new SignatureId("V2", 0x7109871A);
-    public static final SignatureId V3 = new SignatureId("V3", 0xF05368C0);
-    public static final SignatureId V31 = new SignatureId("V31", 0x1B93AD61);
-    public static final SignatureId STAMP_V1 = new SignatureId("STAMP_V1", 0x2B09189E);
-    public static final SignatureId STAMP_V2 = new SignatureId("STAMP_V2", 0x6DFF800D);
-    public static final SignatureId PADDING = new SignatureId("PADDING", 0x42726577);
-    public static final SignatureId NULL = new SignatureId("NULL", 0x0);
+    public static final SignatureId V2 = new SignatureId("V2", 0x7109871A, 0);
+    public static final SignatureId V3 = new SignatureId("V3", 0xF05368C0, 1);
+    public static final SignatureId V31 = new SignatureId("V31", 0x1B93AD61, 2);
+    public static final SignatureId STAMP_V1 = new SignatureId("STAMP_V1", 0x2B09189E, 3);
+    public static final SignatureId STAMP_V2 = new SignatureId("STAMP_V2", 0x6DFF800D, 4);
+    public static final SignatureId PADDING = new SignatureId("PADDING", 0x42726577, 9999);
+    public static final SignatureId NULL = new SignatureId("NULL", 0x0, 999);
 
     private static final SignatureId[] VALUES = new SignatureId[]{
             V2, V3, V31, STAMP_V1, STAMP_V2, PADDING, NULL