If you participate in a virtual currency fundraiser, take a good look at all the conditions of these Initial Coin Offerings (ICO), at the risk of losing everything.

This is the story that investors in the Swiss startup Tezos - specializing in blockchain technology - are currently living through, through the creation of a new secure transaction system.

This summer, they participated in a $ 232 million virtual currency fundraiser in the company co-founded by Frenchman Arthur Breitman and his wife Kathleen.