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Hello,

I own a few RPN calculators (HP-15c, HP-16c, WP-34s, HP-42s) and I was wondering if I could use one of them to store passwords for the few (maybe 25~) login credentials that are required for work or internet in general. Some passwords are as long as 20 characters.

While I own a few RPL calculators (various generations of the HP-48, HP-49, HP-50), I think those are too big to carry on a daily basis, while the RPN ones are easy to carry in a pocket, making it the ideal companion for data storage.

The volume of data is about 25 passwords, times 20 characters and a 8 character description per password, hence 25*20*8 = 4KB. Due to the unfrequent updates, those could be stored in firmware, in the case of the WP-34s, but this isn't a strong requirement.

This password store would have to be protected by a password or combination of keys; their encryption would be nice, but isn't a strong requirement.

Let me know if this has been done or if this is even doable.
Thank you,
Jerome

I think that your data size calculation off and you could certainly do something clever to compress the data since the number of different characters used in a password is quite small.

However, the issue that you will have on some of those calculators would be displaying all the characters necessary. Numerals and Alpha might be OK on some, but if you follow good password practices and use special charcters, that would pose a problem.

What about an old PDA? A Palm M500 will run for a very long time on a charge, and you can load Free42 on it.

Or if you want something more modern, an iPod Touch loaded with Free42, and an encrypted password database app (I use mSecure, but there are lots to choose from). Plus you could do remote desktop/ssh/vnc, which, while not ideal, can certainly save your butt in a pinch.

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What about an old PDA? A Palm M500 will run for a very long time on a charge, and you can load Free42 on it.

Or if you want something more modern, an iPod Touch loaded with Free42, and an encrypted password database app (I use mSecure, but there are lots to choose from). Plus you could do remote desktop/ssh/vnc, which, while not ideal, can certainly save your butt in a pinch.


I'd rather carry a 48gx or 50g than a Palm or Ipod, as imho, the hp is a much more capable device; at least for the work I do; and the keyboard makes things much easier than emulators. It looks like this might be the best solution at the moment. Sadly, though, since I would have preferred to carry something that fits in a pocket and work on batteries.

For pocketability and alphanumeric capability, your list boils down to the WP 34S and the HP-42C. Either can store and display arbitrary length alpha strings as needed only limited by memory by using scrolling. The main limit may be the desire to secure the data so anyone who picks it up can't just see all your passwords with just a button press or two.

As you point out, since the WP 34S source is available you could easily replace some of the internal functions you don't use with dedicated ones for passwords, perhaps requiring a specific numeric input for them to supply an output (or to supply the correct one). Security through obscurity - who would ever know you have that? And, unlike the HP-42C, the WP 34S is more easily replaced if it falls out of your pocket or otherwise is lost / damaged / destroyed (perish the thought!).

Finally, an orthagonal approach may be to use one of the on-line secure password storage sites or, if you don't trust them, put your own home PC online acting as one. Or even an inexpensive server such as the RasberryPi, Shiva Plug or such, running code that malware won't even recognize or try to infect. Then carry the calculator you want to actually use for your work and let the Web help you with Web stuff. Or wear a Casio DataBank watch. Lots of possibilities...

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As you point out, since the WP 34S source is available you could easily replace some of the internal functions you don't use with dedicated ones for passwords, perhaps requiring a specific numeric input for them to supply an output (or to supply the correct one).

This is a really good idea, I'm going to look into the feasibility of this.