Make "Kerberos interrealm authentication does not scale" into a number: tabulate the pairwise key exchanges needed for 2 to 100 realms, then measure what doubling the realm count costs.
Make "Kerberos interrealm authentication does not scale" into a number: tabulate the pairwise key exchanges needed for 2 to 100 realms, then measure what doubling the realm count costs.
Answer
def exchanges(n): return n * (n - 1) // 2 print("realms key exchanges") for n in [2, 5, 10, 20, 50, 100]: print("%-7d %d" % (n, exchanges(n))) for n in [10, 50]: print("N=%d -> N=%d multiplies the work by %.2f" % (n, 2 * n, exchanges(2 * n) / exchanges(n)))