SWP based secure element
I would like to comment a detail of the article about the SWP technology. This last one is blamed as the one contributing to make the transaction too long.
The SWP technology is entirely defined in the TS 102.613 ETSI standard and is designed to address a split system: the NFC controller dealing with the RF NFC protocol and the secure element in charge of the secure applications. The propagation time through the NFC controller (compliant with the standard) is predictable and cannot exceed a maximal time. Any engineer can compute it and precise what the time spent within the NFC controller and the time spent in the secure element.
More than 80% of the transaction time is related to computations within the secure element. For instance, the impact of the SWP technology on the transaction time is about 3%!!
Why the secure element is slow?
The processing time is directly related to the Mifare Desfire protocol itself (number of cryptographic operations, writing in non volatile memory,..) but not only!
The processing time depends mainly of the way the secure element is powered. In most of the cases, the secure element is under powered (18 mW max) and the secure element maker is obliged to set low frequency CPU and so gets a low power of computation.
Beside that, there is a big difference between a secure element hosting multiple programmable applications able to be downloaded other the Air (OTA) and a contactless card hosting a single application running on a dedicated operating system (Mifare Desfire OS). Here we cannot have the cake and eat it: a flexible multi-application platform as JavaCard able to be programmed and the performance of an optimized platform dedicated to a single native application!!
I hope the few explanations above may help the readers of this article to not make wrong assumptions about the root cause of the issues related the these new NFC-capable mobile phones.
Best regards, A.