security: Generate random block in Tpm.

Change-Id: Ia65d32802ed0ebc76605ae7975ea02f4c2db737d
diff --git a/src/security/sec-tpm-memory.hpp b/src/security/sec-tpm-memory.hpp
index 38bc5ff..69f5052 100644
--- a/src/security/sec-tpm-memory.hpp
+++ b/src/security/sec-tpm-memory.hpp
@@ -107,6 +107,9 @@
   virtual void 
   generateSymmetricKeyInTpm(const Name& keyName, KeyType keyType, int keySize);
 
+  virtual bool
+  generateRandomBlock(uint8_t* res, size_t size);
+
   /**
    * Check if a particular key exists.
    * @param keyName The name of the key.