The NFC Forum, a non-profit industry association that advances the use of NFC technology, announced the adoption and release of the Logical Link Control Protocol (LLCP) specification, which supports bi-directional communications between NFC-compliant devices.
The organization also announced the new NFC Signature Record Type Definition (RTD) candidate specification, which defines how to digitally sign data records in NFC Data Exchange Format (NDEF) messages. Both specifications are available to the public for download at no charge at here.
Formerly a candidate specification, the adopted LLCP technical specification defines an OSI layer-2 protocol to support peer-to-peer communication between two NFC-enabled devices – essential for any NFC applications that involve bi-directional communications, such as the exchange of electronic business cards, the transfer of a Web URL from one phone to another, or the initiation of Bluetooth communications.
The specification defines two service types, connectionless and connection-oriented, organized into three link service classes: connectionless service only; connection-oriented service only; and both connectionless and connection-oriented service. The connectionless service offers minimal setup with no reliability or flow-control guarantees (deferring these issues to applications and to the reliability guarantees offered by ISO/IEC 18092 and ISO/IEC 14443 MAC layers). The connection-oriented service adds, in-order, reliable delivery, flow-control, and session-based service layer multiplexing.
LLCP is a compact protocol, based on the industry standard IEEE 802.2, designed to support either small applications with limited data transport requirements, such as minor file transfers, or network protocols, such as OBEX and TCP/IP, which in turn provide a more robust service environment for applications. The NFC LLCP thus delivers a solid foundation for peer-to-peer applications, enhancing the basic functionality offered by ISO/IEC 18092, but without impacting the interoperability of legacy NFC applications or chipsets.
The Signature RTD candidate technical specification helps users verify the authenticity and integrity of data within NDEF messages by specifying the format to be used when signing single or multiple NDEF records. It defines the required and optional signature RTD fields, and also provides a list of suitable signature algorithms and certificate types that can be used to create the signature. It does not define or mandate a specific Public Key Infrastructure (PKI) or certification system, nor does it define a new algorithm for use with the Signature RTD.
The Signature RTD specification remains a candidate for final release pending feedback from NFC Forum members and other standards organizations. By releasing candidate specifications, the NFC Forum enables organizations in the NFC ecosystem to begin integrating them into their own work. This gives both NFC Forum members and other standards organizations an opportunity to accelerate their development and provide valuable feedback that can be incorporated into the final specifications. Once the feedback has been evaluated and integrated, the Signature RTD specification will be officially adopted and released by the NFC Forum.