Suppose that the key generation is insecure; each key bit is independently generated, but the value of each key bit is '$1$' with probability $0.90$. These keys are used in AES. What is an efficient attack against these weak keys.
The only thing I know is that a randomly chosen key has a lot of $1$s. But from this I don't know how to continue. Can someone give some hint on how to continue?
I have read here but I don't understand.