Device Code Phishing

This isn’t new, but it’s increasingly popular:

The technique is known as device code phishing. It exploits “device code flow,” a form of authentication formalized in the industry-wide OAuth standard. Authentication through device code flow is designed for logging printers, smart TVs, and similar devices into accounts. These devices typically don’t support browsers, making it difficult to sign in using more standard forms of authentication, such as entering user names, passwords, and two-factor mechanisms.

Rather than authenticating the user directly, the input-constrained device displays an alphabetic or alphanumeric device code along with a link associated with the user account. The user opens the link on a computer or other device that’s easier to sign in with and enters the code. The remote server then sends a token to the input-constrained device that logs it into the account…

February 19, 2025
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Pairwise Authentication of Humans

Here’s an easy system for two humans to remotely authenticate to each other, so they can be sure that neither are digital impersonations.

To mitigate that risk, I have developed this simple solution where you can setup a unique time-based one-time passcode (TOTP) between any pair of persons.

This is how it works:

  1. Two people, Person A and Person B, sit in front of the same computer and open this page;
  2. They input their respective names (e.g. Alice and Bob) onto the same page, and click “Generate”;
  3. The page will generate two TOTP QR codes, one for Alice and one for Bob;
February 10, 2025
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