Let's suppose I have a 1MB high-resolution photo and I want to hash and create a 1536-bits key.
I know that I could just use SHAKE-256 as its a pre-enginered way for doing that.
There is also Skein that can emit outputs of any sizes (up to 2^64-1).
But Skein has a internal state of 1024-bits.
If I decide to use Skein to generate the 1536-bits key, would I have the same security of that of SHAKE-256 despite Skein internal state being shorter than the key size? Would the key have guaranteed 1536-bits of security?
PS: I read the entire Skein manual and I could not find anything that can answer this question.