--- /dev/null
+// Define byte offset of key within context structure.
+#define ContextKey 0
+
+/* Define byte offset of key length within context structure. The number
+ stored there is the number of bytes from the start of the first round key
+ to the start of the last round key. That is 16 less than the number of
+ bytes in the entire key.
+*/
+#define ContextKeyLength 240