John Cantrell, Bitcoin and Lightning Network project developer, recently revealed he had successfully hacked a Bitcoin address. His article, however, received a number of responses with many concluding Bitcoin isn’t secure. Cantrell felt people missed the point of the exercise so, in a tweet thread on June 19, explained and ensured people that despite hacking a wallet, Bitcoin is still safe.
Takes forever to crack the wallet
According to Cantrell, bitcoins stored in a wallet generated from a 12-word mnemonic is secure. The only reason why he was able to hack the Bitcoin wallet was because the wallet’s owner publicly exposed eight words from his 12-word mnemonic seed. He explained:
“It would take the same system that brute forced the last 4 words of his mnemonic 837 quintillion millennium to brute force all possible 12 word mnemonics [...] if you know as few as 5 words. To brute force all 12 words (just to break even on your $100B investment, assuming you can actually liquidate all the BTC) still takes 422 TRILLION YEARS.”
The only way Bitcoin is not secure is when seed words are revealed. “Your bitcoin is safe. 2^128 is a REALLY big number. Just don't let anyone near your seed words,” he concluded.