What purpose does a performance appraisal serve?

1)  What purpose does a performance appraisal serve? What are some key ideas to remember when conducting a performance appraisal? What best practices have you seen? What would you change and why? 2)  1). Using the Web or other resources, write a brief paper about RSA, its      history, its methodology, and where it is used.     2). Send a brief message (ten words minimum) using the Caesar Cypher.