diff --git a/SM4-with-AESENCLAST.md b/SM4-with-AESENCLAST.md
index 8e47f62..50d7b62 100644
--- a/SM4-with-AESENCLAST.md
+++ b/SM4-with-AESENCLAST.md
@@ -11,4 +11,10 @@ A1(x) = M1*x + C1
 A2(x) = M2*x + C2
 ```
 
-The combinations of (M1, C1, M2, C2) or (A1, A2) are not unique.
\ No newline at end of file
+The combinations of (M1, C1, M2, C2) or (A1, A2) are not unique.
+
+Two known (M1, C1, M2, C2), please reference [sm4 with AESENCLAST](https://gist.github.com/emmansun/ae4677d71c75ff8407d5f5b3a884f5d2), my question is how to generate all (M1, C1, M2, C2)? 
+```
+{(M1, C1, M2, C2) | SM4-S(x) = A2(AES-S(A1(x)), A1(x) = M1*x + C1, A2(x) = M2*x + C2}
+```
+