 Hello everyone, my name is Yobin Shen. Today I'm going to talk about our action clip paper, key-reduced variant of 3KM9 with beyond-burst-bound security. This is joint work with Fodina Cypria. 3KM9 is the three key CBC type mark that enhances the standardized integrated algorithm F9. This is also called 3GPP mark. It is a sequential mode without field multiplication and has beyond-burst-bound security and is expected to be a post-broke needed in constrained environment, that we instance with that we block cypher. The problem to reduce the number of key of 3KM9 is the 3GProperance. Two variants of 2KM9 and 1KM9 were proposed to reduce key size for efficiency. But recently, for the 1KM9, low-run at all has proposed their burst-bound attack by exploring the fixed function. For a 2KM9, subsequently, Shen at all also proposed one-carry attack and also a similar attack when the fixed function is added and saw this attack invaded that layer security pools. In this work, we revisit previous construction of key-reduced variant of 3KM9 as light and analyzable when known in security analysis. Interestingly, we find that a single doubling at the end cannot only fix 2KM9 to go beyond the burst-bound security but also have 1KM9 to go beyond the burst-bound security. Here is our proposal and 2KM9. We simply add a single doubling near the end. The single doubling can be achieved by one base shift and one conditional echo with some constant which can be very efficient. For one key version, here is the 1KM9. We also add a single doubling at the near the end. But here is an additional constraint that the mainstream space should be prefixed free as the original cb-smart. There is no query as a prefix of the other. This requires an approval but not a text currently. If we compare n2KM9 with an eMark, n2KM9 can provide a higher security guarantee with one additional block-several code and one doubling. The top part can be regarded as an eMark, let the last block is always zero. For n2KM9, the security bound is beyond the burst-bound security. This security bound can be improved for while the eMark, the security bound is only burst-bound and the bound is typed so there is no room to improve this bound. We will compare n1KF9 with the cb-smart. There you also provide a higher security guarantee with only one conditional block-several code and one doubling. Similarly, the top part can also be regarded as a cb-smart where the last block is always zero. The bound of n1KM9 is beyond the burst-bound security. This bound may be improved for while the bound for the cb-smart is only burst-bound. The bound is typed so there is no room to improve it further. As a conclusion, we propose a two-new key-reduced variant of n2KM9 with beyond burst-bound security. Compared to eMark and cb-smart, the additional codes to provide a higher security guarantee is expected to be minimal for n2KF9 and n1KF9. It only requires one additional block-several code and one doubling. Thanks.