Well to say, keyword itself is the answer.
When you create a crossword, the algorithm tries to fit the randomly selected keywords and fit them in the grid. And when a user want to solve it, he will not be shown the keywords, instead shown its questions. He needs to predict the keyword and enter in the grid. If he enters them correctly, the crossword will be solved.
In this, the keyword is known to the submitter of that. So if you are creating a crossword, your questions will not be included in that (as you know the keyword for it :) )
When opportunity is in front of you, don't hesitate to catch it. It will never come to you again. - Maverick
