I would like to implement some ECDSA functionalities into an NFC microchip (generating keypairs, signing, etc.), with NDEF communication.
I am wondering if JavaCards suits that need (size, power, protocol, performances, ECDSA acceleration, etc.), or if I'd rather use more dedicated hardware (e.g. banking secure element) with lower level software layer such as a dedicated firmware (the one I'm targeting is http://www.tiempo-secure.com/product/dual-interface-secure-chips/).
Thank you very much!
Mario.
Related
Can someone explain what is the difference/relationship between the two?
Now I'm using GPShell + globalplatform + pcsclite too manipulate the NFC-enabled card. From my point of view (I don't know much about libnfc) pcsclite and libnfc do the same.
pcsclite (or rather PC/SC in general and not just the pcsclite implementation)
PC/SC is a smartcard API for the personal computer platform (initially mainly destop computers, but also servers, etc and even smartphones and other embedded systems). So PC/SC is a standard that provides interoperability between arbitrary smartcard readers and arbitrary PC platforms from different manufacturers. pcsclite is the implementation of this interoperability layer (from developer point of view basically providing a standardized API that is idependent of the smartcard and reader platform as well as the target OS). PC/SC comes from times before contactless smartcards and has since been extended to contactless smartcards and contactless memory cards.
libnfc
libnfc is a library for NFC controller chips and provides a standardized way to access an NFC interface. While this also permits access to contactless smartcards and memory cards/NFC tags, NFC controllers have much more capabilities (peer-to-peer mode communication and (host) card emulation). These capabilities are covered by libnfc (btw, there is not really a standard* defining the interfaces and layers of the software stack behind libnfc as is with PC/SC).
*) This is starting to change with the NFC Forum's NCI specification (at least for the lower levels).
To summarize, pcsclite is for access to smartcard readers (that could also be contactless smartcard readers) and libnfc is for access to NFC interfaces (which are something different than smartcard readers, though they may sometimes be used for the purpose of reading contactless smartcards). So, libnfc and pcsclite simply have a different purpose and comparing them is pretty much like comparing apples and oranges.
I am very new to the smart cards and I think I have misunderstood some things.
I want to be able to sign messages using ECDSA with the card's private key(s). Also have some custom logic for key derivation.
Is it possible with Mifare DESFire? If not, what other NFC smart cards could do that?
Thanks
No, MIFARE DESFire is a memory card (with some additional protection mechansims for authentication/access control and encryption) so it's not possible to run custom code on such a card. DESFire cards only have symmetric keys for authentication and support only (3)DES and AES (only EV1) encryption of the exchanged data.
If you want to be able to create digital signatures and do other asymmetric cryptography with a card, I suggest you look into processor smartcards. Besides contactless cards with pre-loaded cryptography applications, I suggest you look into Java Cards if you want to create your own card-side applications or if you want some existing open-source applets like OpenPGPcard. Note that you need to make sure that the card contains an asymmetric co-processor with support for ECDSA if you want to create an application that performs ECDSA signatures.
Keep in mind, however, that the NFC interface of mobile phones is typically designed for interaction with low-power NFC tags. Consequently, communication with processor cards (particularly in combination with cryptography) may result in problems.
Not on desfire but just get any smart card with contactless capabilities and implement something like ndef on top of it. Like Yubikey NEO's applet that generates a NDEF message with OTP keys, for example.
I'm new to the NFC standards and I have only played with Ntag203, Mifare Classic and Desfire. I'm trying to figure out what is the advantage of Desfire for our application.
I have looked through ISO 14443 and ISO 7816-4 standards and I can only figure out that the Desfire provides a standards compliant API to manage encryption to ensure interoperability between OEM client applications, readers and cards.
Let's say I am building a mobile client that needs to encrypt and store data using the same scheme as Desfire (AES or 3DES) - can I do that completely client side with , say ntag203, and not violate any security standards.
I have worked with PCI-DSS and am worried if this is some kind of mandatory technology to be able to process sensitive data like health records, payment balance, etc
For my master thesis I'm investigating the possibility to use an NFC enabled phone for opening off-line door locks. These locks currently work with DESFire cards which contains authorisation data. Furthermore, the card is also used to update configurations and obtain maintenance messages to/from the lock. The goal is to update and read this information to/from the lock via an application on the phone that communicates with an external server over the internet ultimately making the exchange of this information more efficient.
Currently, I think the best choice for getting card emulation to work is to use an SD card with NFC and a secure element. This provides two possibilities:
1) A possibility is to implement a custom made java card applet that emulates a DESFire card. Theoretically, this should be feasible as DESFire cards optionally supports APDUs (ISO7816).
2) Some of the NFC SD cards available on the market offer DESFire emulation as a ROM.
I've the following questions:
For option 1 I wonder what will happen if the off-line lock / reader initiates communication using DESFire 'native' commands instead of APDUs. Is it possible to interpret non-APDU commands from java card? If not, it probably means it will not work?
Is it possible to manage the content of an emulated DESFire card in option 2? The NFC SD cards that I saw provides a proprietary API to access the secure element. It allows this by transceiving APDUs. The emulated DESFire, however, is not a java card applet in this case but it is a ROM which may or may not support this communication with APDUs.
I know this question is not strictly related to programming. But I found that there are quite some people on stackoverflow with expertise on NFC related topics. In fact, I found most of my information here.
Thanks
In order to answer 1 you would need to examine carefully ETSI 102 705 and see if the API lets you process CLT events (lower level protocol exchanges) instead of the contactless chip. I think this is unlikely.
In option 2 there surely is a way to manage the contents, otherwise the proposed desfire emulation would be totally worthless, but this might end up being partly proprietary, or requiring a substantial effort in cryptography, in which case you need to obtain the right keys.
All in all, if I were you, I would do ISO7816 (14443-4) card emulation using javacard, and forget about all the NXP proprietary stuff, which is built to make you buy licenses and associated software solutions.
I am often being asked about standards, the NFC is based on. I summarized my knowledge in the text below. I hope it can be an answer to such questions. Please feel free to correct it by posting comments and replies - I will include it into my text.
Since NFC is based on RFID, it is often seen as RFID extension, its form or subset. It is correct because many existing standards from RFID were adopted in the NFC. The NFC base standard for physical layer is NFCIP-1 (ISO 18092 or ECMA 340) - it standardizes communication between two NFC devices. The RF layer use in the NFCIP-1 is directly inherited from older ISO standards ISO 14443 (proximity contactless cards) more specifically the Type A protocol defined in that standard, and on Japanese JIS 6319-4 (on which Sony FeliCa is based, also used by the NFC Forum Type 3 Tag standard). The consequence of that is that NFC devices (reader/writer mode) is compatible with ISO 14443 smart cards.
NFCIP-1 defines newly the active mode. In this mode in which both communicating NFC devices must have own source of power for generating RF fields (i.e. two mobile devices or mobile device and NFC reader) and both can be initiators of the communication.
The 2nd major standard is NFCIP-2 (ISO 21481 or ECMA 352), which defines selection mechanism between different contactless technologies that operates on the same frequency 13.56Mhz. It is intended to be used by mobile devices that support communication according to ISO 18092, ISO 14443, but they be also compatible other contactless standards like ISO 15693.
In addition to that NFC Forum released also couple of other standards like NDEF (data format) RTD (record types for various purposes), and recommendations for NFC Handover and in particular use of the NFC for Bluetooth pairing. The Wi-Fi Alliance introduced NFC as the one of four ways to configure home networks.
NFC forum also defined LLCP protocol used on the top of NFCIP-1 in peer-to-peer communication. Another protocol used in peer-to-peer communication on the top of the LLCP is SNEP (Simple NDEF Exchange protocol), which allows the exchange of NDEF messages analogous to tag operation specifications.
NFC devices can in addition work in card emulation mode, which allows them to pretend they are passive contactless smart cards. This might be the most important mode, since it allows the mobile phones act as contactless payment cards. There are couple of standards for interconnection of NFC controller with secure element (element used for storing secure applications and sensitive data) used in card emulation mode - SWP (Not standard yet - see ETSI TS 102 613 V.9.1.0) and NFC-WI (ECMA-373).
I am not 100% sure about above text correctness, so my question is - is it correct or not? Is there anything you would add?
BR
STeN
Added comments from NFC guy
I am not sure your questions belong on SO, as they are not related to programming. Stil, I have some comments and additions.
NFC-IP1 is based on ISO 14443, more specifically the Type A protocol defined in that standard, and on JIS 6319-4 (on which Sony FeliCa is based, also used by the NFC Forum Type 3 Tag standard). NFC-IP1 is not based in any way on ISO 15693.
I don't think it is necessary for a device to support NFC-IP2 to be considered an NFC-enabled device. Also, LLCP does not require active mode.
When talking about NFC standards, I would also mention SNEP (Simple NDEF Exchange Protocol), which uses LLCP to exchange NDEF messages. Next to Bluetooth handover, NFC Connection Handover has also been standardized for WiFi by the WiFi Alliance.
Connecting a secure element to an NFC controller: the protocol is called SWP (not SWI). This protocol is typically used to connect a SIM card as a secure element to the NFC controller.
Another standard you may find worth mentioning is ISO 7816-4, as that is used by the NFC Forum Type 4 Tag standard.
ISO15693 standards compatibility was added in fall 2015 or so by NFC Forum.