Blockchain technology has gained importance in theprevious years. Emerging through cryptocurrencies like Bitcoinin the early 2010s, it is now used in various fields like power grid,smart cars, or bank transactions. With the growing interest inblockchain, the question of their security became important, sodoes the question of their performances.

A centreal question is the differences between Proof-of-Workand Proof-of-Stake. Proof-of-Work is a mechanism used by alarge majority of the current blockchain. Introduced by Bitcoin,it lacks in performance and needs large resources. On the otherhand, Proof-of-Stake is an alternative which allows blocks to bequickly created and with a lesser energy consumption, but at theexpense of the security.

The objectives of this thesis are to study these two mechanisms,their advantages and vulnerabilities, and, if it is possible, to finda mechanism with both the efficiency and low consumption ofProof-of-Stake and the security of Proof-of-Work, and also tostudy the application of DLTs to improve the security of IT andOT systems.