  Game G: Clare passes a string s which is either from perfect random number
generator R0 or from good imperfect number generator R1, with equal
probability. Alice's information about whether it is from R0 or R1 is bounded
by small value h. Alice use s as the input random numbers for QKD protocol with
Bob. Suppose Eve may have very small information about the final key if s is
from R0 and Eve has large information if s is from R1, then after the protocol,
Alice announce the final key, Eve's information about whether s is from R0 or
R1 is unreasonablly large, i.e., breaks the known bound, h. Explicit formulas
are given in the article.
