I. INTRODUCTION  
II. SMART GRID OVERVIEW  
A. Smart grid’s features  
B. Smart grid’s conceptual model  
C. Smart grid’s systems  
D. Smart grid’s network protocols  
III. SECURITY REQUIREMENTS OF SMART GRID  
A. Confidentiality  
B. Availability  
C. Integrity  
D. Accountability  
IV. CHALLENGES AND FUTURE DIRECTION  
V. CONCLUSION