Auction is a promising approach for dynamic spectrum access in Cognitive Radio Networks. Existing auction mechanisms are mainly proposed to be strategy-proof to stimulate bidders to reveal their valuations of spectrum truthfully. However, they would suffer significantly from a new cheating pattern named false-name bids, where a bidder can manipulate the auction by submitting bids under multiple fictitious names. We show such false-name bid cheating is easy to make but hard to be detected in dynamic spectrum auctions. To resolve this issue, we propose ALETHEIA, a novel flexible, false-name-proof auction framework for largescale dynamic spectrum access. ALETHEIA has the following important features: (1) it not only guarantees strategyproofness but also resists false-name bids, (2) it enables spectrum reuse across a large number of bidders, (3) it provides the bidders the flexibility of diverse demand formats, and (4) it incurs low computational overhead. Simulation results show tha...