About Bitcoin Gold (BTG)

Bitcoin Gold is a hard fork of the cryptocurrency Bitcoin. The fork occurred in late October 2017, on block 491407. The purpose of the fork is to create an ASIC resistant Bitcoin, by reusing Equihash proof-of-work algorithm from Zcash. The token debuted at #5 on CoinMarketCap. Between 12-15 November 2017 users of Bitcoin Gold started reporting that their wallets were being emptied of various cryptocurrencies including Bitcoin, Bitcoin Gold, Ether (Ethereum) and Litecoin. Investigations revealed that an open source wallet found on mybtgwallet.com and linked to from the Bitcoin Gold website was stealing users' master passphrases or "recovery seeds" used to generate the private keys for multi-wallets containing multiple cryptocurrencies.

At first the BTG development team issued statements to the media that the wallet was "modified by unknown parties long after it was originally published". They later changed their statement after it became apparent that the website wasn't hacked and the developer, going only by the name "John Dass", broke all communication with the team. Some users reported that they only used the wallet on 12 November when Bitcoin Gold's mainnet was launched and subsequently had their funds transferred between 14 and 15 November. It's still not known who changed the website code and installed a broken security certificate after the keys were stolen so that it would look like it was hacked.

An analysis revealed that the code contained a line to convert the entered passphrases into Google Analytics cookies that could later be retrieved. Altogether more than 440 Bitcoin worth more than $3 million at the time together with unknown amounts of Bitcoin Gold, Ether and Litecoin were transferred from users' wallets. On 26 November 2017 the Bitcoin Gold team issued a statement that their Windows wallet contained on their Github repository contained a file of "suspicious origin". The team stated: "Until we know otherwise, all users should presume this file was created with malicious intent - to steal cryptocurrencies and/or user information. The file does not trigger antivirus / anti-malware software, but do not presume the file is safe." It further advised users to check their computers for malware and move all wallet funds to new addresses.

Source: Wikipedia