56 страниц. 2012 год. LAP Lambert Academic Publishing The author deeply analyzed the concepts of cryptography, and look at the detailed study of symmetric key algorithms. Performances are evaluated of various symmetric key algorithms on Dot NET framework by taking different input sizes. All algorithms are implemented and evaluated on base 16 and base 64. So, the Computations are done on different hardware systems. It gives different values depend on hardware, software platforms and also on input sizes. In this, running time execution is taken as main parameters on which evaluation of various symmetric key algorithms are analyzed. There has a lot of scope of future in evaluating these algorithms by taking more other parameters and which helps us for more detailed study of these symmetric key algorithms.