According to my point of view The  first online cryptocurrency exchange based on block chain technology has been started in Belarus the world's first  regulated  tokenized securities exchange,, financially supported by London-based Belarusian entreprenuer a Russian business man .The online service allowed users to exchange different types of cryptocurrencies and also to sell and buy for national currencies .Block chain technology makes online transactions faster and more secure and as well as anonymous .Token may be used to safe guard sensitive data such as bank accounts  or financial  statements  the decree makes initial coin offerings and transactions in crypto currencies legal and all such trades will not be taxed.till the year 2023 .