Properties with 10% Down payment?

[Martin Phillips]

Hello I want to know if this would be legal, what If I were to find an apartment owner to give me a percentage of my down payment for the bank say 10% and I pay the other 10? Alternately what If he pays me this 10% after I have financed the deal contingent on it's purchase? So I put up the 20 percent down payment and then he returns me 10 percent after the deal?