Is it possible that all current blockchain-based cryptocurrencies (like Bitcoin) can be hacked in just a matter of seconds? It indeed seems possible, based on the statements made by Dr. Joseph Liu, Associate Professor at Monash University.
Dr. Lius qualifications add allot of weight to his statements. He is the Head Researcher at Monash Blockchain Research Lab, the Chief Scientist of HCash and he is also the co-creator of the Moreno cryptocurrency. In other words, his statements about cryptocurrency development should be taken seriously...
https://www.bitcrypt.co/every-cryptocurrency-hacked-in-seconds/