diff --git a/mirai-core/src/commonMain/kotlin/network/protocol/data/proto/Msg.kt b/mirai-core/src/commonMain/kotlin/network/protocol/data/proto/Msg.kt
index 024acbb75..f75d75fc9 100644
--- a/mirai-core/src/commonMain/kotlin/network/protocol/data/proto/Msg.kt
+++ b/mirai-core/src/commonMain/kotlin/network/protocol/data/proto/Msg.kt
@@ -13,9 +13,12 @@ import kotlinx.serialization.Serializable
 import kotlinx.serialization.protobuf.ProtoIntegerType
 import kotlinx.serialization.protobuf.ProtoNumber
 import kotlinx.serialization.protobuf.ProtoType
+import net.mamoe.mirai.internal.utils.io.NestedStructure
+import net.mamoe.mirai.internal.utils.io.NestedStructureDesensitizer
 import net.mamoe.mirai.internal.utils.io.ProtoBuf
 import net.mamoe.mirai.internal.utils.structureToStringIfAvailable
 import net.mamoe.mirai.utils.EMPTY_BYTE_ARRAY
+import net.mamoe.mirai.utils.unzip
 
 @Serializable
 internal class ImCommon : ProtoBuf {
@@ -538,10 +541,26 @@ internal class ImMsgBody : ProtoBuf {
 
     @Serializable
     internal class LightAppElem(
+        @NestedStructure(LightAppElemDesensitizer::class)
         @ProtoNumber(1) @JvmField val data: ByteArray = EMPTY_BYTE_ARRAY,
         @ProtoNumber(2) @JvmField val msgResid: ByteArray = EMPTY_BYTE_ARRAY,
     ) : ProtoBuf
 
+    internal object LightAppElemDesensitizer : NestedStructureDesensitizer<LightAppElem, ByteArray> {
+
+        // unzip
+        override fun deserialize(context: LightAppElem, byteArray: ByteArray): ByteArray {
+            if (byteArray.isEmpty()) return byteArray
+
+            return when (byteArray[0].toInt()) {
+                0 -> byteArrayOf(0) + byteArray.decodeToString(startIndex = 1).toByteArray()
+                1 -> byteArrayOf(0) + byteArray.unzip(offset = 1).decodeToString().toByteArray()
+                else -> error("unknown compression flag=${byteArray[0]}")
+            }
+        }
+
+    }
+
     @Serializable
     internal class LocationInfo(
         @ProtoNumber(1) @JvmField val longitude: Double = 0.0,
diff --git a/mirai-core/src/commonMain/kotlin/utils/io/ProtocolStruct.kt b/mirai-core/src/commonMain/kotlin/utils/io/ProtocolStruct.kt
index c3692f328..f4a0686f0 100644
--- a/mirai-core/src/commonMain/kotlin/utils/io/ProtocolStruct.kt
+++ b/mirai-core/src/commonMain/kotlin/utils/io/ProtocolStruct.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2021 Mamoe Technologies and contributors.
+ * Copyright 2019-2022 Mamoe Technologies and contributors.
  *
  * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
  * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@@ -21,6 +21,6 @@ internal annotation class NestedStructure(
     val serializer: KClass<out NestedStructureDesensitizer<*, *>>
 )
 
-internal interface NestedStructureDesensitizer<in C : ProtocolStruct, T : ProtocolStruct> {
+internal interface NestedStructureDesensitizer<in C : ProtocolStruct, T> {
     fun deserialize(context: C, byteArray: ByteArray): T?
 }
\ No newline at end of file