I came up with this concept, which I thought would be pretty secure.
So the idea is this, you have a message $M$, which you split up in blocks of each 256 bits. You generate a random (pseudo-random of course) key of $256$ bits. You XOR the first block of $M$ with this key, which is also the input key for the second block, and so on. Would this be a secure scheme? My theory is that since XOR has the property that if you were given
$Z = X \oplus Y$
You can't extract $X$ nor $Y$ from $Z$
So you would have to guess every key in the 256 bit keyspace and go through this "encryption" process and see if you get some logical output.
So, would this be safe?