diff --git a/PKHeX/PKM/PKMConverter.cs b/PKHeX/PKM/PKMConverter.cs
index 6da5762e1..251d27857 100644
--- a/PKHeX/PKM/PKMConverter.cs
+++ b/PKHeX/PKM/PKMConverter.cs
@@ -297,7 +297,14 @@ namespace PKHeX.Core
             switch (format)
             {
                 case 1:
-                case 3: // TOneverDO, nobody exports encrypted pk3s
+                case 2: // no encryption
+                    return;
+                case 3:
+                    ushort chk = 0;
+                    for (int i = 0x20; i < PKX.SIZE_3STORED; i += 2)
+                        chk += BitConverter.ToUInt16(pkm, i);
+                    if (chk != BitConverter.ToUInt16(pkm, 0x1C))
+                        pkm = PKX.decryptArray3(pkm);
                     return;
                 case 4:
                 case 5: