In November last year, researchers Joe Grand and Bruno, using insights into a flawed password generator, successfully cracked an 11-year-old password, unlocking Michael's $3 million cryptocurrency wallet initially thought irretrievable.

When "Michael," a cryptocurrency owner, reached out to Joe Grand two years ago asking for assistance in regaining access to almost $2 million worth of bitcoin that Grand had kept on his computer in an encrypted format, Grand declined.

Michael, a European who has requested to remain anonymous, kept the cryptocurrency in a digital wallet that required a password to access. He used the RoboForm password manager to create a password, which he then saved in an encrypted file using TrueCrypt. The 20-character password Michael had created to protect his 43.6 BTC (worth a total of roughly €4,000, or $5,300, in 2013) was lost when that file became corrupted.

Michael created the password using the RoboForm password manager, but he didn't keep it in ...