Based on a first look, this appears to be... genuine:
> The letter is signed by Professor Duncan Buell, Ph.D., Chair Emeritus — NCR Chair in Computer Science and Engineering, Dept. of Computer Science and Engineering, University of South Carolina; David Jefferson Ph.D., Lawrence Livermore National Laboratory (retired), Election Integrity Foundation; Susan Greenhalgh, Senior Advisor for Election Security, Free Speech For People; Chris Klaus, Chief Executive Officer, Fusen World; William John Malik, Malik Consulting, LLC; Marilyn R. Marks, Executive Director, Coalition for Good Governance; Peter G. Neumann Ph.D., Chief Scientist, SRI International Computer Science Lab; and Professor John E. Savage, Ph.D, An Wang Professor Emeritus of Computer Science, Brown University.
Ugh.