# LED cryptography algorithm

I would like to better understand the operation of the LED algorithm, especially the process of substitution and permutation of the blocks and especially the use of the keys in each round.

The keys in each round are expansions of a single key or keys are different?

https://www.cryptolux.org/index.php/Lightweight_Block_Ciphers#Zorro

https://eprint.iacr.org/2012/600.pdf

But could not find if each round are expansions or are different keys.

"Note that for a 64-bit key $K$, all subkeys are equal to $K$, while for a 128-bit key $K$, the subkeys are alternatively equal to the left part $K^1$ and to the right part $K^2$ of $K$."