function cancelBid(address bidder, bytes32 seal) {
        Deed bid = sealedBids[bidder][seal];
        
        if (address(bid) == 0 
            || now < bid.creationDate() + initialAuctionPeriod 
            || bid.owner() > 0) throw;

        
        bid.setOwner(msg.sender);
        bid.closeDeed(5);
        sealedBids[bidder][seal] = Deed(0);
        BidRevealed(seal, bidder, 0, 5);
    }