rich1.0npub1xg2m84malu0cfm4444r0kysx4rgk27e75aj6sz6538kw8fcz627qeadsv7https://nostr.ae/npub1xg2m84malu0cfm4444r0kysx4rgk27e75aj6sz6538kw8fcz627qeadsv7njumphttps://nostr.ae📅 Original date posted:2014-03-07 📝 Original message:On 03/07/2014 10:26 AM, Johannes Zweng wrote: > In current phone implementations, the screen must be on already for NFC > to be active. Also it must be unlocked, although I certainly hope future > OSes will allow payment apps on the lock screen, just like they allow > music players. > > Just a small input to this point: > On Android 4.4 the new host card emulation (HCE) feature (aka: the phone > emulates a ISO-DEP Smartcard and processes ISO7816-4 APDU commands like > a Smartcard would do) only works when the display is on, but even when > the screen is locked (can be changed with "android:requireDeviceUnlock" > in Manifest). See here for detailled > specification: http://developer.android.com/guide/topics/connectivity/nfc/hce.html > > Using the HCE API on Android 4.4 also has the beauty that any app that > registers itself for HCE and sets its category to CATEGORY_PAYMENT in > the Manifest automatically shows up in Adroid's system settings under > "Tap & Pay" (where a user would expect payment applications). Thanks for the pointer! Good to hear there is finally a decent documentation for HCE. Good news: HCE offers the required dispatch ability -- they call it AID (Application ID). Bad news: It seems - at least CATEGORY_PAYMENT - very credit card centric. HCE seems to cover only the payer side. I wonder if there is also an API for "reader emulation" which we would need for apps to support the payee side. Since Android 4.4 market penetration is quite far off, I suggest we focus on the already established NFC payment protocol(s) for now, it works pretty well. I will investigate into IsoDep and HCE and see if we can make it enhance usability. Interesting side note: They recommend messages transmitted via NFC to not exceed 1 KB in order for a snappy experience. This (again) questions usage of bulky X.509 certificates in our payment request messages. Bitcoin Wallet currently does not sign payment requests, so I could not try how it would feel.