The creation of 2.04 million BTCP "that never existed on the blockchain". Bitcoin Private, has been officially confirmed by the developers of the altcoin Bitcoin Private (BTCP). Bitcoin Private is a cryptocurrency that was issued as a result of merging the blockchain data of bitcoin and ZClassic. On December 23, analysts from Coin Metrics published a report stating that during the import of the blockchain data an additional 2.04 million BTCP (about $3.9 million at the time of publication) were secretly minted. According to the project's official documents, the total supply of BTCP is about 20.4 million, whereas the secret minting of BTCP brought "the initial supply up to 22.6 million".

The BTCP team stated that after examining the data in the Coin Metrics report they "immediately launched an investigation to determine whether the alleged conclusions about the additional quantity of BTCP coins were true". After conducting an internal audit, the team confirmed that Coin Metrics' conclusions were "mathematically accurate". The developers discovered that a single line was missing from the code, which "allowed forged blocks to be accepted". It is reported that a hacker exploited this error, creating more than 2 million BTCP. The statement says that since the code was open-source, "anyone with sufficient knowledge of blockchain development could have used the exploit". The BTCP team also stated that it was unaware of the incident until the publication of the Coin Metrics report. The altcoin's network uses the zk-SNARK protocol, which allows coins to be stored at hidden (shielded) addresses. According to Coin Metrics, it is on these that the secretly minted coins are held, along with a relatively small portion (about 20 thousand) of legitimate coins. The developers decided to destroy all coins at the shielded addresses through a hard fork (sacrificing the legitimate coins in the process). The team also proposed an even more radical solution to the community — to destroy all BTCP coins that have never been moved (more than 12 million).