 Hi everyone, this is Constructive Post-Quantum Reductions. Assumed you have a classical reduction between two cryptographic primitives. For example, assume you have a proof by reduction of the security of your encryption scheme based on some post-quantum secure assumption. But the reduction is classical, which means that if you have an adversary against the encryption scheme, you can translate it into an adversary for the underlying assumption. Now, does having this reduction mean that your encryption scheme is quantumly secured? Is it secure against the quantum adversary? Well, at first glance, it may seem that it is the case, but in this paper, we show that we need to think a little bit more carefully about what this actually means. So we want to argue that if you have a quantum adversary that violates the security of the encryption scheme, then you also get a quantum adversary against the underlying assumption. But one has to be careful in the quantum case. In particular, if the adversary that violates security of the encryption scheme actually has an internal quantum state. And the reason is that the internal quantum state can actually change once you call, once you invoke this attacker. And therefore, it's not even clear that you can use this attacker more than once. So these questions, this type of questions are what we deal with in this paper, and we show some positive results. So for some classes of reductions, you actually can infer from having a classical reduction that you would also have a quantum reduction, or a reduction for the quantum case. In some cases, we actually show that there are barriers, even in the sort of easier case of non-interactive, non-interactive class of primitives. So Neer is going to give the topic crypto, and it should be great, do come.