{"type":"rich","version":"1.0","author_name":"npub1xg2m84malu0cfm4444r0kysx4rgk27e75aj6sz6538kw8fcz627qeadsv7","author_url":"https://nostr.ae/npub1xg2m84malu0cfm4444r0kysx4rgk27e75aj6sz6538kw8fcz627qeadsv7","provider_name":"njump","provider_url":"https://nostr.ae","html":"📅 Original date posted:2014-03-07\n📝 Original message:On 03/07/2014 10:26 AM, Johannes Zweng wrote:\n\n\u003e     In current phone implementations, the screen must be on already for NFC\n\u003e     to be active. Also it must be unlocked, although I certainly hope future\n\u003e     OSes will allow payment apps on the lock screen, just like they allow\n\u003e     music players.\n\u003e \n\u003e Just a small input to this point:\n\u003e On Android 4.4 the new host card emulation (HCE) feature (aka: the phone\n\u003e emulates a ISO-DEP Smartcard and processes ISO7816-4 APDU commands like\n\u003e a Smartcard would do) only works when the display is on, but even when\n\u003e the screen is locked (can be changed with \"android:requireDeviceUnlock\"\n\u003e in Manifest). See here for detailled\n\u003e specification: http://developer.android.com/guide/topics/connectivity/nfc/hce.html\n\u003e \n\u003e Using the HCE API on Android 4.4 also has the beauty that any app that\n\u003e registers itself for HCE and sets its category to CATEGORY_PAYMENT in\n\u003e the Manifest automatically shows up in Adroid's system settings under\n\u003e \"Tap \u0026 Pay\" (where a user would expect payment applications).\n\nThanks for the pointer! Good to hear there is finally a decent\ndocumentation for HCE.\n\nGood news: HCE offers the required dispatch ability -- they call it AID\n(Application ID).\n\nBad news: It seems - at least CATEGORY_PAYMENT - very credit card centric.\n\nHCE seems to cover only the payer side. I wonder if there is also an API\nfor \"reader emulation\" which we would need for apps to support the payee\nside.\n\nSince Android 4.4 market penetration is quite far off, I suggest we\nfocus on the already established NFC payment protocol(s) for now, it\nworks pretty well. I will investigate into IsoDep and HCE and see if we\ncan make it enhance usability.\n\nInteresting side note: They recommend messages transmitted via NFC to\nnot exceed 1 KB in order for a snappy experience. This (again) questions\nusage of bulky X.509 certificates in our payment request messages.\nBitcoin Wallet currently does not sign payment requests, so I could not\ntry how it would feel."}