On Mon, Apr 4, 2011 at 11:49 PM, JMC114 <[email protected]> wrote:
> Hey Michael, > > Thank you very much for you elaborate answer. As you suggested, I did > not distinguish between smart cards and NFC tags. > > I have several follow-up questions regarding your answer. > > *Regarding P2P communication* > > - If I understand correctly, Android uses a proprietary protocol > (which I believe is called com.android.npp) on top of LLCP as > specified by the NFC Forum, which is a protocol on top of NFCIP-1 as > specified in ISO 18092. I read in another discussion in this group > about a spec on com.android.npp that's due to be published, is there > any information as to a specific date for this publication? Or is > there any other (documented) way for regular terminals or desktop > readers to communicate with an Android phone over P2P? > Just want to clarify this - NPP is an open protocol. We've published the spec here: http://source.android.com/compatibility/ndef-push-protocol.pdf > > *Regarding Card Emulation* > > - How would installation of an application on the SE work? // How > would permission be given, and to whom? I don't yet clearly see how > this would work in practice. > > - And more specifically, how would one develop and test an application > for the SE, if it requires permission by the SE owner. > > - You mentioned it's possible to emulate a card with some tweaking of > the android source, how far could you go with this? Any pointers? > > Either way, thank you very much for you clarification on card > emulation and the different NFC modes. > > Thanks, > JMC > > On Apr 4, 2:07 pm, Michael Roland <[email protected]> wrote: > > Hallo JMC, > > > > I think there is a big misunderstanding out there of whatcardemulation > > is (and what it is not!). > > > > First of all, NFC has three different communication modes: > > * Reader/writer mode, > > * Peer-to-peer mode, and > > *Card-emulationmode > > > > *Reader/writer mode* is used to access NFC tag (i.e. tags that comply to > > the tag formats specified by the NFC Forum and contain NDEF data). > > Moreover, this modes provides compatibility to existing RFID (13.56MHz, > > inductive, proximity coupling)cardinfrastructures (i.e. you can > > interact with contactless smart (and memory) cards, like MIFARE, > > ePassports, ...) > > The Nexus S supports reader/writer mode for 3 (4) contactless standards: > > - ISO/IEC 14443 Type A (e.g. MIFARE) and Type B > > - JIS X 6319-4 (that's FeliCa) > > - ISO/IEC 15693 (that's vicinity coupling cards, which is not NFC > > but uses a similar communication technique also in 13.56 MHz) > > > > *Peer-to-peer mode* is used for direct communication between two NFC > > devices (e.g. two mobile phones, but an NFC device can be pretty much > > anything). This mode lifts the restrictions imposed by an "active reader > > -- passivecard" system. Thus, in a classic RFID/smartcardsystem there > > is a reader device that starts and controls the communication with one > > or multiple cards, and cards that process commands received by reader. > > Whereas, in a peer-to-peer system any device can start (and control) the > > communication with any other device. > > Peer-to-peer mode is used to exchange any data between NFC devices. This > > data can be as simple as NDEF messages, but it's even possible to tunnel > > other network protocols like IP over a peer-to-peer link. > > The Nexus S supports the peer-to-peer protocol (NFC-DEP, ISO/IEC 18092) > > with LLCP (NFC Logical Link Control Protocol) on top. With the current > > API level only a simple exchange of NDEF messages (with Android's > > proprietary protocol on top of LLCP) is possible. > > > > *Card-emulationmode* is used to emulate a contactless smartcardwith > > an NFC device. This mode provides compatibility to existing RFID > > (13.56MHz, inductive, proximity coupling) reader infrastructures. An NFC > > device incard-emulationmode acts the same as any "real" contactless > > smartcard. > > Withcardemulationit is important to notice the difference between a > > _contactless smart card_ and an _NFC tag_: > > > > - An NFC tag is a contactless transponder that has a certain memory > > layout and contains standardized data elements (NDEF messages). > > Four such layouts are defined by the NFC Forum (tag types 1 to 4). > > Tag type 1 is based on Innovision's Jewel tags, tag type 2 is > > based on NXP's MIFARE Ultralight. So I would not consider these > > two "smart" cards (they are more like simple memory cards). Tag > > type 3 is based on FeliCa and tag type 4 is based on the ISO/IEC > > 7816-4 smartcardstandard. Therefore, the latter certainly are > > smart cards. Yet, in this case an NFC tag is a smartcardwith a > > specific file layout (i.e. acardthat contains the "NDEF > > application"). > > Besides the standardized NFC tag formats, vendors like NXP have > > created guidelines for using their contactlesscardtechnologies > > (e.g. MIFARE Classic) as NFC tags. > > An NFC tag is only data storage and doesn't have (may have but > > not use) special security features like data encryption, ... > > > > - A smartcardcan be much more than an NFC tag. A smartcardcan > > contain, for instance, a credit/debitcardapplication, a > > ticketing application for public transport ... > > These applications have even existed before NFC. They DO NOT use > > the NDEF format to exchange data. Instead they use their own > > protocols (e.g. EMV for payment cards). Often they use special > > security features of smart cards (high security execution > > environment, highly secure data storage, cryptographic > > processing power ...) > > > > So thecard-emulationmode allows theemulationof a contactless > msartcard(and not an NFC tag, although the smartcardcould *possibly* be > > used as NFC tag). As applications like credit cards typically have high > > security requirements,cardemulationis not handled by the NFC device > > itself (i.e. the application processor of an NFC-enabled mobile phone). > > Instead, the NFC device has a dedicated hardware component (the > > so-called Secure Element) that handles all thecardemulation. (*) > > > > (*) This is not entirely true, as some NFC controllers (like the > > PN544) would theoretically allow theemulationof ISO/IEC > > 14443-4 contactelss smart cards from the application processor. > > Yet, I don't know of any NFC phone that makes this functionality > > available to the user and I rather doubt that this will become > > available on the Nexus S. > > > > The Secure Element (SE) is typically a smartcarditself. But instead of > > a normal contact/contactless smartcardinterface it has a connection to > > the NFC controller, which connects it to the NFC antenna. > > > > The Nexus S has an integrated SE (a SmartMX combined into the same > > package as the PN544 NFC controller). This SmartMX emulates a ISO/IEC > > 14443 (Type A) smartcardand a MIFARE Classiccard. > > In addition to this integrated SE it is possible to use a special UICC > > (also known as SIMcard) that supports the Single Wire Protocol (which > > is an interface designed for the communiction between the NFC controller > > and a UICC) as the SE. > > > > So the Nexus S will definitly support theemulationof contactless smart > > cards (with a bit of tweaking the Android sourcesthis is already > > possible to some extent). Yet, the SE is a protected environmentwhere > > you can't simply install your application. Instead, you have to ask the > > owner for permission to install your application. The "owner is not the > > user who bought the device but instead the device's vendor. So, for the > > internal SE of the Nexus S it is Samsung/Google(?) who decide who gets > > access to the SE. For the UICC it is your telco who decides this. > > > > As a consequence an "NDEF application" will most likely not make it into > > the SE. So you won't be able to use your phone as *NFC tag*. But there > > is not much use for this anyways as a device that understands NDEF would > > most likely be an NFC device that also supports peer-to-peer mode. > > > > To summarize this,cardemulationwill certainly become available for > > the applications you mentioned. But it will not be used to transport > > *NDEF data* between devices. > > > > br, > > Michael > > > > On 02.04.2011 22:45 JMC114 wrote: > > > > > > > > > > > > > > > > > Hey Michael, > > > > > Why - may I ask - do you think this possibility will not be made > > > available to android phones? It seems to me it's a rather important > > > part of NFC. The part where it makes phones compatible to existing > > > infrastructures based on RFID (without changing those > > > infrastructures), namely those in public transport, building access, > > > charge points for electric driving, etc. > > > > > I - for one - believe the general public's adoption of NFC technology > > > strongly depends on this. > > > > > Thoughts? > > > > > Gr, > > > JMC > > > > > On Mar 23, 11:03 am, Michael Roland <[email protected]> wrote: > > >> Hallo, > > > > >> the current SDK does not allow you to usecardemulation. > > > > >> Anyways, withcard*emulation* you will not be able to simulate an > > >> *NFC tag* (i.e. a tag where you store simple NDEF messages).Card > > >>emulationmode allows to emulate a contactless smartcard (typically > > >> used for applications with high security requirements, like credit > > >> cards). While such acard(emulated or real) can be used to carry NDEF > > >> messages, I really doubt that this possibility will be made available > > >> for the Android phones. > > > > >> br, > > >> Michael > > > > >> On Mar 23, 5:14 am, Zhihong GUO <[email protected]> wrote: > > > > >>> Hi all, > > > > >>> about NFC in Gingerbread, is it possible to simulate a tag by the > SDK? I > > >>> have found the support for tag read/write and P2P push message, but > haven't > > >>> found any support oncardsimulate. > > > > >>> thanks > > > > >>> James > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en > -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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