DIY USB password generator

Posted on Wednesday, December 5th, 2012 in PCBs, security, USB by the machinegeek

Benjamin Lunt writes to inform us of a small hardware HID project which for which he’s developed a PCB. The device design was created by Joonas Pihlajamaa (Jokkebk) and posted on CodeAndLife where it’s very popular. Joonas’ device is a small USB HID keyboard device that types a password stored in EEPROM every time it’s attached. As shown above, a new password can be generated just by tabbing CAPS LOCK a few times (4 times to start password regeneration and one tab for each password character generated, 10 is the default password length). The design is based on an ATTiny85 and a few resistors and zener diodes.

Ben went on to develop the PCB design be found on his website. Additional docs and pics can be found at CodeAndLife.

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This entry was posted on Wednesday, December 5th, 2012 at 3:01 pm and is filed under PCBs, security, USB. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

2 Responses to “DIY USB password generator”

  1. Very cool! Would be an interesting experiment to implement a Hardware RNG using a zener diode as a noise source! I have some cryptographer friends and they get very picky about their RNGs ;)

  2. Alvin Chang says:

    Joonas has a new blog port about my project inspired by his DIY USB password generator at

    Come check it out!

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