 Hi, I am Ashwin Jha, I will be presenting the paper towards tight security bounds for OMAC, XCBC, and TMAC at AsiaGrid 2022. This is a joint work with Shomo Jotapathya and Mirzul Nandi. In my presentation, I will be focusing on four main points. First, I will describe OMAC, XCBC, and TMAC, which are popular CBCMAC variants. Note that CMAC and ISO standard and NIST recommended algorithm is just a simple variant of OMAC. So, our results implicitly apply to CMAC as well. Second, I will discuss the existing security bound, which says that the security holds up to the square root of 2 to the N over L queries, where N is the block size of the block cipher and L is the maximum message length. Third, I will talk about the tightness of the existing bounds. Interestingly, there is no matching attack for the existing bound, and the general belief is that the bounds can be improved up to the minimum of square root of 2 to the N and 2 to the N over L. So, the existing bounds have a quadratic degradation as compared to the four-core bound, and it was not clear up to now how it can be improved. Finally, I will present our improved bound, which effectively says that the security holds up to the minimum of square root of 2 to the N and 2 to the N over L squared queries. While we do not achieve the four-core bound due to the additional L factor, our result is still an improvement over the existing bounds. To get an idea of the quantitative improvement, take N equals 128 and consider this graph of the number of queries versus the maximum message length. Here black curve denotes the existing bound and red curve denotes the four-core bound. Obviously, there is a clear daylight between the two bounds. Now if we put the new bounds, that is the curve in green, you can see that our bounds are very close to the four-core bounds up to the message length of 2 to the 30 blocks or roughly 64 gigabyte, and are still better than the existing ones up to roughly 64 terabyte long messages. For further details, I will invite you to my IshaGrip talk. Thank you.