At a glance, the passwords the LLMs created looked secure, much like those that a password generator might spit out. But that’s exactly where the problems arose: Although the AI-generated passwords appeared to be complex and safe to use for securing online accounts, they were actually quite predictable upon closer inspection.

All three LLMs exhibited clearly identifiable patterns in how they created these passwords. These patterns included repeated character strings, predictable password structure, frequent reuse of similar characters, clear biases toward certain numbers and letters, and even duplicate passwords in some cases. Although the AI-generated passwords looked random, they really weren’t. This could easily create a false sense of security if you were to use these predictable passwords for your online accounts.