diff --git a/Asec.h b/Asec.h
new file mode 100644
index 0000000..136ad3b
--- /dev/null
+++ b/Asec.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _ASEC_H
+#define _ASEC_H
+
+struct asec_superblock {
+#define ASEC_SB_MAGIC 0xc0def00d
+    unsigned int magic;
+
+#define ASEC_SB_VER 1
+    unsigned char ver;
+
+#define ASEC_SB_C_CIPHER_NONE    0
+#define ASEC_SB_C_CIPHER_TWOFISH 1
+#define ASEC_SB_C_CIPHER_AES     2
+    unsigned char c_cipher;
+
+#define ASEC_SB_C_CHAIN_NONE 0
+    unsigned char c_chain;
+
+#define ASEC_SB_C_OPTS_NONE 0
+    unsigned char c_opts;
+
+#define ASEC_SB_C_MODE_NONE 0
+    unsigned char c_mode;
+} __attribute__((packed));
+
+#endif