BTCP is one of many bitcoin hard forks that emerged in the past two years. It is a merge fork of Bitcoin and Zclassic (which is a fork of Zcash). The fork occurred in February 2018, primarily as a result of developers wanting to create a more privacy-focused version of Bitcoin that took elements from Zcash/Zclassic. Hard forks are often done because of legitimate disagreements between developer communities. However, many have also accused the various Bitcoin forks of being nothing more than cash and opportunity to make money while capitalizing on bitcoins name.
The discovery was first made by digital assets analytics website ‘Coinmetrics’. The site published a report declaring that “2.04 million units of altcoin BTCP — about $3.9 million at the time of the discovery, were secretly minted”.
BTCP responded by launching their internal investigation to verify if the claims were true. They discovered that the allegations were ‘mathematically accurate’, explaining that after a BTCP developer had solved an issue, they merged their code, but left one line missing, “allowing the fork mine to be exploited due to the nodes not properly verifying the falsified fork blocks.”
This developer collected their bounty for fixing the issues, then left the project.
The bug created by the merged code was later exploited to generate more than 2 million new coins when the BTCP fork was announced.
“As the code was open source, and the fork-mine was announced on Twitter, anyone with sufficient blockchain development knowledge could have exploited it.”
“This particular exploit could only be taken advantage of during the fork mine, which already occurred earlier this year. Therefore, it is impossible for this particular bug to exploit to occur again, nor can it be further exploited.”
– BCTP dev. Team.
At this time, the BCTP team still has not uncovered who is responsible for creating 2 million coins from the blockchain.
According to BCTP teams official statement, less than 20k legitimate BTCP coins exist in shielded addresses along with 1.7–1.8 million illegitimate coins. BCTP is considering a hard fork to remove all shielded coins from existence. Although this would cause the 20k legitimate coins to disappear, the BCTP team believes this is preferable to the alternative of leaving the 1.7–1.8 million illegitimate coins in circulation, and have stated that this would also fix the over-supply issue.