On Tue, 22 Jan 2002, Newsmail wrote: > hi people, is there anyone who could give me an url that describes how > smart cards work, and what are they good for. I mean, I read about cipher > performances on smart cards, but actually I dont understand how can I store > keyfiles on smartcards, or how all this thing works. I asked a many people, > but nobody was able to give me an answer. if someone could help me, I'M > looking forward to it. thx > Regards, > Greg > > ps: I'M mostly interested about storing encrypted keyfiles on smartcards, > and so on. I have not programed them myself, so this is not firsthand experience. Smart cards are in fact often small computers on a single chip on a credit card (or credit card sized card). They are typically based on old 8-bit chips, especially the 8051 chip and have quite limited amounts of RAM, typically 128 or 256 _bytes_, and about 8192 bytes of ROM/EPROM/FLASH. No, it is not kilobytes or megabytes but bytes. This makes them extremly cheap (like $0.5), but programming them is challenging. They can also be memory card with 64 or more bytes of RAM. There are also more powerful card that use 16 bit processors (typically ARM-processors) and have more memory available. This is more expensive, so they have not been so much used as the lowend cards. Typically usages for lowend cards are decoder cards and credit cards. For symmetric crypto, a low end card can be used. For public key crypto the low end card is usually not powerful enough, and you need either special purpose hardware or a more powerful card. Thats probably the reason that many of the highend cards are markeded as 'crypto cards' and are designed to not leak information, and may have crypto hardware on it. On such cards the private key never needs to leave the card. It can be generated on the card, and the public key exported. Everytime something needs to be decrypted or signed, it can be given to the card, and the card does the job on the onchip processor. To use a smartcard you must have a smartcard reader and driver to it, and you must communicate with the card via a specific protocols. I have an impresson that quite a lot of these are properitary, but there is open standards as well. There is a HOWTO on linuxdoc: http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/Smart-Card-HOWTO.html -- Gisle Sælensminde ( gisle@ii.uib.no ) With sufficient thrust, pigs fly just fine. However, this is not necessarily a good idea. It is hard to be sure where they are going to land, and it could be dangerous sitting under them as they fly overhead. (from RFC 1925) - Linux-crypto: cryptography in and on the Linux system Archive: http://mail.nl.linux.org/linux-crypto/
