Last week, privacy-focused crypto altcoin GRIN made news after the development team received a donation from an early Bitcoin whale interested in supporting future development of the budding technology built on a unique blockchain protocol called Mimblewimble, after Happy Potter lore.

Now this week, that whale may regret the donation, as a former Google engineer and computer scientist has discovered a new attack that "breaks Mimblewimble's privacy model" and uncovers as much as 96% of the addresses associated with the privacy altcoin.

Former Google Engineer Publishes Successful Attack on Privacy Altcoin

Russian computer scientist and former Google engineer Ivan Bogatyy, has revealed via a detailed Medium post, that he has discovered an attack vector that allows the developer to expose the exact addresses of the senders and receivers of 96% of all GRIN transactions in "real-time."

The developer claims that GRIN's protocol, Mimblewimble, is "fundamentally flawed," and unfixable, even going as far to say that the Mimblewimble-based cryptocurrency "should no longer be considered a viable alternative to Zcash or Monero when it comes to privacy."

Bogatyy says he was able to use only $60 per week of spend on Amazon Web Services to use the attack to expose the addresses of the privacy coin.