In this paper we present known-plaintext single-key and chosen-key attacks on round-reduced LED-64 and LED-128.
We show that with an application of the recently proposed slidex attacks,
one immediately improves the complexity of the previous single-key 4-step attack on LED-128. Further, we explore the possibility of
multicollisions and show single-key attacks on 6 steps of LED-128. A generalization of our multicollision attack
leads to the statement that no 6-round cipher with two subkeys that alternate, or 2-round cipher with
linearly dependent subkeys, is secure in the single-key model. Next, we exploit the possibility of finding pairs of inputs that follow
a certain differential rather than a differential characteristic, and obtain chosen-key differential distinguishers
for 5-step LED-64, as well as 8-step and 9-step LED-128. We provide examples of inputs that follow the 8-step differential,
i.e. we are able to practically confirm our results on 2/3 of the steps of LED-128. We introduce a new type of
chosen-key differential distinguisher, called random-difference distinguisher, and
successfully penetrate 10 of the total 12 steps of LED-128. We show that this type of attack is generic
in the chosen-key model, and can be applied to any 10-round cipher with two alternating subkeys.
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