Yubikey NEO OpenPGP advisory

Julian H. Stacey jhs at berklix.com
Mon Apr 27 16:51:50 CEST 2015

> Thanks for the hints, guys. But I'm very happy with my current leather
> wallet, and the bag I keep the wallet in is almost full. So I'm more
> looking for something really compact around the card, like a sleeve.
> getDigital has one: [1]. I just can't judge how sturdy it is; the sleeve
> I have seen in real life looked like it was quite a hassle to remove
> your card from because it looked really flimsy.
> Peter.

I make my own RF blockers, though un-tested yet :
For maybe 10 years my business cards have been made from 80 gram/
square metre paper, folded once & cut to size, then heat sealed
into plastic, hot lamination pouches, using 2 alternate products:
  Leitz 100x Credit Card Hot seal laminating pouches 125 (250) mic
    1 Leitz 33810 bar code 5 411313 338103
  Ibico ibi pouches for hot laminating credit card 54 x 86 mm
    100 pouches . clear . 5 mil 125 micron permanently sealed & protected

Years back I realised I could cut some aluminium cooking foil to
same size as the paper, & seal that as an RF / microwave test tool,
then an RFC card arrived, & I inserted the metal foil `card' behind
the NFC credit card, on the outside of the wallet.

The metal foil in sealed plastic puch is a much slimmer (0.26 mm)
than a credit card (0.8 mm), so fits well in same wallet slot as an NFC
enabled credit card (metal foil on outer side of wallet of course.

As cards are stacked offset in a wallet I assume it make sense to
decide where on the credit card the NFC chip is, for max overlap
of the foil.

I made a larger foldable excapsulated foil pouch for my brother's
wallet, (he had NFC cards before I did). I can't remember what
thickness plastic I used + 2 for British passports (some kind of chip).

I haven't tested them yet, just use them :-) I recently got an NFC
app to convert my Android phone into an NFC reader on USB coupled
to a PC, so I will test it some time, but :
A) I dont normally carry my NFC card, &
B) I haven't looked beyond 

If aluminium cooking foil is too thin, some are thicker than others,
& I have some thin copper sheet too, but I doubt it will need that.

I've long been planning to insert aluminium foil in the new
version of my business cards, which BTW look like this

I guess computer clubs could create similar cards, with foil blockers.
I bought my hot laminator long ago, it does up to A4 size, since
then prices for laminators have crashed, & credit card sized ones
even cheaper, probably most on this list can with local friends
club together & buy/ share a laminator, & make ther own blockers,
but we need to check how effective they are :-)

Julian Stacey, BSD Linux Unix C Sys Eng Consultant Munich http://berklix.com
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