The only public network Hashgraph consensus algorithm is Hedera Hashgraph. Hedera goes beyond blockchain to create a quick, equal, and safe environment that allows businesses to implement distributed ledger technologies. This thesis focuses on the security level of the Hashgraph and the possible attacks. Therefore, different Hashgraph potential vulnerabilities are discussed and evaluated in depth in this thesis. In addition, we demonstrated and explained deeply the various Hashgraph attacks and how they can be used. As a result, this thesis includes some countermeasures and suggestions for avoiding them. In addition, various experiments were applied to showcase the normal scenarios as a control reference and possible attacks scenarios. Fur thermore, a theft prevention experiment is demonstrated were it shows how to bullet proof your transactions when using Hedera Hashgraph consensus. As a result, the aim of this thesis is to make Hashgraph more resistant to attacks while still making it safe to use in realistic applications.