BBC News reports short passwords are becoming increasingly insecure due to advances in GPGPU password cracking tools. A research team at Georgia Tech Research Institute says seven-character passwords are now hopelessly inadequate, and recommend people to use a 12-character (or longer) combination of upper and lower case letters, symbols and digits.
Longer passwords take longer to crack and offer better protection, say the researchers.
"Right now we can confidently say that a seven-character password is hopelessly inadequate," said Mr Boyd, "and as GPU power continues to go up every year, the threat will increase."
A better alternative, he suggested, would be a 12-character combination of upper and lower case letters, symbols and digits.
Ultimately, suggest the researchers, users may be forced to rely on whole sentences that are a mix of different sorts of characters to ensure no-one else can guess their password and get at online services.