Friday, February 13, 2015

HCE: The User Experience That Nobody Talks About

Host Card Emulation (HCE) is an incredibly enabling technology. For Android developers there are a few nuances to be aware of in the form of OS rules. Not understanding how these rules apply can have a negative impact and create an embarrassing or awkward customer experience if the system should render a 'payment failure'. Here are four scenarios to keep in mind to avoid point-of-sale issues.

Avoid The Embarrassment



The only limiting factor for the NFC radio in an Android device is whether or not the screen is lit up. What that means is that the NFC radio will turn on and could be ready for an HCE transaction is:

screen is dark:    NO
screen is lit:       YES

That rule alone is an Android rule, not an application rule, and so the application will have the ability to further limit this HCE experience if it wants to.

To support the best user experience, an application must be able to respond and complete an HCE transaction on demand if the screen is lit up. This should hold true even if:

1) application is running in the foreground
2) application is running in the background
3) application is NOT running at all because android has "repo'd" or removed it from running memory, or not started at all since a re-boot of the phone.
4) application is NOT running and a time based  Limited Use Key has expired since the application stopped running

The 1st and 2nd cases above are the easy ones as transaction data can be store in the running application memory space.

Here is how android works on the 3rd and 4th scenarios. When the phone antenna engages the terminal antenna and the terminal requests a particular AID, then the android OS looks at that AID request from the terminal and decides which Card Emulation Service to startup based on the "Tap and Pay" menu options.  That service is NOT your app, it is a component of your application that is expected to respond to APDU requests from the terminal. An APDU stands for Application Protocol Data Units.  The challenge is that the service will most likely not contain the APDU data to respond with as the rest of the application is not currently running at that time and the data required may not be loaded. It would require that the APDU data that the reader is asking for actually must be persistent in some way on the device so that the service could get access to it and answer the terminal properly with card data.

There are a few ways to store data locally, but the point is that it must happen in order to respond to the reader in time for a proper user experience. We have noted that simply expecting the application to be running on the phone at tap time is simply not reliable and that in a 24 hour window, it the app is not used, then Android has likely removed that application from memory.

This is just food for thought as you are thinking of designing your own HCE application or using a vendor like ST.  By the way, the SimplyTapp SDK supports all 4 scenarios listed above. The 4th is slightly more complicated, but i'll leave it up to you to noodle at.


51 comments:

  1. isn't your service going to receive the APDU payload as param? as, in order to be a HCE service, it must extend android.nfc.cardemulation.HostApduService

    https://developer.android.com/guide/topics/connectivity/nfc/hce.html#ServiceImplementation

    ReplyDelete
    Replies
    1. Great Article
      android based projects





      Java Training in Chennai

      Project Center in Chennai

      Java Training in Chennai

      projects for cse



      The Angular Training covers a wide range of topics including Components, Angular Directives, Angular Services, Pipes, security fundamentals, Routing, and Angular programmability. The new Angular TRaining will lay the foundation you need to specialise in Single Page Application developer. Angular Training

      Delete
  2. I will be reading about this article tomorrow in my classroom and then our teacher will review and explain to all of us about it. Thanks for this.

    ReplyDelete
  3. This comment has been removed by the author.

    ReplyDelete
  4. What is it?
    Anthony Joshua defends his status as undisputed heavyweight champion of the world against Andy Ruiz Jr, his first fight since September 2018.

    When is it?
    The fight is on Saturday, June 1, but due to time differences UK viewers may be watching in the early hours of Sunday, June 2

    Where is it?
    Madison Square Garden, New York City. The Manhattan venue is steeped in boxing history having hosted fights involving Muhammad Ali, Joe Frazier and Mike Tyson.

    What TV channel will it be on?
    Sky Sports Box Office have exclusive pay-per-view coverage while viewers in America will be able to watch via streaming service DAZN.

    Joshua vs Ruiz
    Ruiz vs Joshua
    Joshua Ruiz
    Joshua vs Ruiz Live
    Joshua vs Ruiz Live Stream


    When is the Champions League final?
    The Champions League final will take place on Saturday, June 1.

    What time is kick-off?
    Tottenham vs Liverpool kicks off at 8pm, BST.

    What TV channel is it on?
    There is exclusive live coverage on BT Sport 2. Alternatively, you can bookmark this page and return on matchday to follow all the action on our dedicated live blog.

    There are several ways to access BT Sport. If you’re already a BT Broadband customer, you can add BT Sport for nothing for three months and then £10 a month thereafter. For new customers, broadband and television packages start at £34.99 per month.

    Champions League Final
    Champions League Final 2019
    Champions League Final Live
    UEFA Champions League Final

    ReplyDelete
  5. The 2019 Belmont Stakes odds behind favorite Tacitus, who is 9-5. With so little separating the top two choices on Saturday, and plenty of other intriguing value selections on the board, you need to see the predictions from horse racing handicapper Hank Goldberg before making any 2019 Belmont Stakes picks of your own.
    GGG vs Rools
    GGG Rools
    GGG vs Rools Live
    Golovkin vs Rools
    GGG vs Rools Fight

    This story was written in collaboration with Forbes Finds. Forbes Finds covers products we think you’ll love. Featured products are independently selected and linked to for your convenience. If you buy something using a link on this page, Forbes may receive a small share of that sale.
    Belmont Stakes 2019
    Belmont Stakes
    Belmont Stakes Live
    Belmont Stakes Race
    Belmont Stakes Horses

    ReplyDelete
  6. Hey, that's a very unique topic you covered. I wonder if the NFC tag also applies on Quickbooks applications from one phone to another transferring data over android ? that would be even great to know.
    In return you can check this informative blog on how to download and install Quickbooks Tool Hub in order to rectify all the errors that occur in Quickbooks app

    ReplyDelete
  7. This blog is very useful for me, helps me learn a lot. I appreciate your kindness in sharing this useful with you and me!
    Verizon's email service is widely regarded as one of the best in the world. It has a powerful feature set and a fantastic user interface, making it a top-notch emailing platform.
    If you can't remember your Verizon password and are having trouble logging in to your account, you can easily Change Verizon Email Password by visiting our website and following our guidelines.

    ReplyDelete
  8. Very Interesting and wonderfull game keep Download Ludo Online Game

    ReplyDelete
  9. In order to enhance the effectiveness of the accounting it is necessary for the company to take the outsourcing outsourced cfo services

    ReplyDelete
  10. Thank you for posting such a great article. Keep it up mate.

    nhts 2021

    ReplyDelete
  11. quickbooks error 15106 is the most normal error, which is happening when refreshing finance. QuickBooks gives phenomenal alternatives to conquer the blunder and to put it plainly, dispose of it.

    ReplyDelete
  12. You got a really useful blog. I have been here reading for about an hour. I am a newbie and your success is very much an inspiration for me. For instant support related to Common AOL Mail Login Issues please contact our technical expert for help

    ReplyDelete

  13. Thanks for sharing this post .this is the best technical provider ,providing online technical support service including the phone calls and all other services if you are search these kinds of technical sites and all helpful services go through in
    error 1723 quickbook and click on the mentioned link

    ReplyDelete
  14. Thanks for sharing your post it helps me alot for my articles it helps me for better graphics and design for the most important data and more creative ideas you can just check on error 1723 quickbook for this site

    ReplyDelete

  15. Hey, I am an IT student and thanks for updating us with this information this is really nice blog and very informative if you want more information about the article click on

    error 1723 quickbook to visit the site

    ReplyDelete
  16. thank you for sharing your information. I really appreciate your efforts and Thanks a lot for sharing a piece of wonderful information which I am looking for for a longer period of time.it is very helpful for the students because of the nice creativity and animations if you want more click on quickbooks error #15215

    ReplyDelete
  17. Nicely written.
    QuickBooks and Quicken are the world’s most useable accounting software. if you own a little to medium enterprise then the quickbooks was best for you but if individuals and families then the quicken was best for you. here you can compare them quickbooks vs quicken

    ReplyDelete
  18. why won't QuickBooks open might try to open your previous company. Press and hold the Ctrl key, then double-click the QuickBooks Desktop icon. Important: Don't release the Ctrl key until you see the "No Company Open" window unless QuickBooks freezes or gives you an error.

    ReplyDelete
  19. Thanks for sharing this information with all of us actually i have been searching for that for so long and finally i found your page which clear me alot about this and if you want to know what is quickbooks error #15215 then must go to this mentioned link quickbooks unexpected error 5: A QBs Repairing Guide

    ReplyDelete
  20. Quickbooks is one of the leading accounting software providing its users best in class services but sometimes the user get rid of some error one of the error was Quickbooks unrecoverable error when opening the company file this error can occur

    ReplyDelete
  21. Very interesting article. I have written a review on Mcafee antivirus on mcafee.com/activate

    ReplyDelete
  22. May I simply just say what a relief to discover someone that actually knows what they are talking about online. You actually know how to bring an issue to light and make it important.
    메이저사이트
    경마
    온라인경마

    ReplyDelete
  23. A lot more people ought to look at this and understand this side of the story. It’s surprising you aren’t more popular given that you definitely possess the gift.
    바카라
    사설토토

    ReplyDelete
  24. I read your post. It is amazing and helpful information for me. Are you looking for a solution How to Delete Cache App Activity? Cash App Activity is a record of all transaction activity from sending or receiving the money to your contacts. To delete your cache app activity, you have it in the right place. If you have any questions regarding deleting Cash App transaction history, please contact us at our Cash App customer service.

    ReplyDelete
  25. he Indian education system is one of the most complex in the world. There are so many different types of exams, from state to national, that it can be difficult to keep track of what you need to do and when. Whether you're a student looking ahead at the next few years or a parent wondering how to get your child into a good school, this article will give you some insight into some of the Toughest Exams in India 2022.

    ReplyDelete

  26. It’s really nice and meaningful. It’s really cool blog. Thanks for sharing and please update some more information here. Have you been looking for the Zelle customer service support, than you have arrived at the right destination. At this destination you will find the customer service help from zelle, and if you found some issues in using zelle, then you can resolve them by just a click on the given link.

    ReplyDelete
  27. Amazing information. Thanks for sharing with everyone
    If you are looking for a Coin Master Free Spin and Coin Links then it is the right place for you. At this place, you will get the customer service support and 24/7 helpline number of Coin Master Free Spin for this you just have to click on this link.

    ReplyDelete
  28. This is such a great resource that you are providing and you give it away for free. I love seeing blog that understand the value of providing a quality resource for free.
    고스톱

    ReplyDelete
  29. You there, this is really good post here. Thanks for taking the time to post such valuable information. Quality content is what always gets the visitors coming.
    스포츠토토

    ReplyDelete
  30. I like the many blogposts, I seriously liked, I want details about it, since it is rather wonderful., Cheers pertaining to expressing.
    한국야동

    ReplyDelete
  31. All the contents you mentioned in post is too good and can be very useful. I will keep it in mind, thanks for sharing the information keep updating, looking forward for more posts. Thanks!
    토토사이트

    ReplyDelete
  32. This is an amazing blog. Loved it totally. Just visit the offical site of Intuit and click on quickbooks tool hub download and get all your quickbooks errors fixed

    ReplyDelete
  33. Trains, subways, buses, cars, walls, road signs, statues and memorials, bridges, park benches, trees, and billboards are frequently targeted with graffiti. The growing issue of graffiti is predicted to propel the Anti-Graffiti Coatings Market.

    Also Read: https://takeitcool.com/global-anti-graffiti-coatings-market-size-share-key-players-demand-growth-analysis-research-report/

    Read More: Smart Waste Management Market, Europe Biodiesel Market, United States Vaccine Market

    ReplyDelete
  34. Understand How Do I Recover My Cash App Funds By Referring To The Right Source
    Are you not able to understand How Do I Recover My Cash App Funds so that you can apply for a refund to get your money back to your Cash App account wallet? In such a case, you have to simply have a candid discussion with the professionals who will suggest you the right information.

    ReplyDelete
  35. Very useful post. 스포츠토토 This is my first time i visit here. I found so many interesting stuff in your blog especially its discussion. Really its great article. Keep it up.

    ReplyDelete
  36. 스포츠토토티비 Generally I don’t learn article on blogs, however I wish
    to say that this write-up very forced me to try and do
    it! Your writing taste has been surprised me. Thank you, quite nice
    post.

    ReplyDelete
  37. Wow!! Really a nice Article. Thank you so much for your efforts. Definitely, it will be helpful for others. I would like to follow your blog. Share more like this. Thanks Again. for More Information Visit Here:- Install Epson Printer Driver on Mac

    ReplyDelete
  38. The best activator for windows 10However, with Windows 8 regaining a lot of popularity for the Windows brand, it is not surprising that Windows 10 has also been highly successful with tech enthusiasts and users around the world. Combining the best features of Windows 7 and Windows 8, Windows 10 has a lot to offer its wide user base.

    ReplyDelete
  39. The Best cycle under 20000 is among the most popular categories in cycle touring. This range of prices is designed to appeal to the large majority of cycle tourers who are not interested in the most extreme and expensive machines. The key here is comfort and range. You still need the strength and efficiency to make long tours, but you don't need to sacrifice to get there. Hit the link here and get to know Cheapest Best Cycle Under 20000 In India Best cycle under 20000https://gymfever.in/best-cycle-under-20000-in-india/

    ReplyDelete
  40. Hii, this is useful information. Your article is really inspiring me to do the same as you. Visit India if you are interested. An e visa to India is required for travel in India. You may apply online through evisa to India. I found this site & read about and then i used it. In just a few days, I received my India visa online. When errors occurred, they promptly rectified them and understood them. I highly recommend it.

    ReplyDelete
  41. The best windows 10 activator free download for all version for pc With Windows 10 Activator Pro 2022 Crack is permanent patching technique for the Microsoft windows which provide a universal method. It provides you with a statistical approach to make your pc run properly and perform the basic function with full coordination. The best thing about this activator is that, after activation, it generates an update system which aim is to inform you regarding daily updates and other performance of windows. This modern activator fulfills the all modern day requirements which a system need to work without any interruption. It allows all apps to run smoothly and properly work on your system.

    ReplyDelete
  42. Hey! I like your writing skills. Meanwhile, you can create your Kundali By Date of Birth And Time, which might help you in the predictions on several aspects of life.
    Children Astrology | Child Adoption as per Birth Chart | Parent Child Relationship by Kundli

    ReplyDelete
  43. Are you looking for a dependable Gear Box Manufacturer in India? If that's the case, your quest has come to an end with us. Akshi Engineers Pvt. Ltd. can provide you with a high-quality, precision-engineered parallel helical gearbox that may be used in a variety of applications. With gearbox manufacturer India's goods, you may enhance torque, reduce or raise speed, rotate, reverse, or change the direction of the driveshaft in your industrial solutions. For more information, just call the toll-free number and visit our website.

    ReplyDelete
  44. Nice blog. You put up interesting stuff. Thanks for sharing. Do you know what an electronic Indian visa? India e-Visa is an electronic travel authorization launched by the Government of India. You can get more info about categories of India E-Visa via our India visa page.

    ReplyDelete
  45. Elite Cranes Pvt. Ltd. is the leading Manufacturer, Supplier, and Exporter of Industrial Cranes and Material Handling Equipments in India, with its headquarters in Faridabad, Haryana. We offer a wide range of products including EOT Cranes, Single Girder EOT Cranes, Double Girder EOT Cranes, Gantry Cranes, Goliath Cranes, Single Girder Goliath Cranes, Double Girder Goliath Cranes, Semi Goliath Cranes, Overhead Cranes, Jib Cranes, Material Handling Cranes, Industrial Cranes. We have a first-rate solution for the most difficult material handling requirements spanning a wide range of industries.

    ReplyDelete
  46. I enjoyed reading the above article, explained everything in detail, and the article was very interesting and effective. Thank you, and I look forward to hearing from you in the future.

    토토사이트
    토토
    온라인카지노
    바카라사이트
    안전놀이터
    스포츠토토핫

    ReplyDelete
  47. Your openness in sharing your wisdom and thoughts is sincerely admirable and deeply valued. I want to share some news for everyone. New Zealand Opens Borders To Visa-Waiver Nations As Travel Resumes. As a result, people of nations qualified for visa-waiver entrance can now travel to New Zealand without a visa. This action is a part of the nation's attempts to restore its tourist sector and once more welcome visitors from abroad. The entrance procedures, such as giving the required health information and following any quarantine or testing measures, still apply to travelers.

    ReplyDelete
  48. I must say, your blog is absolutely fantastic! The way you seamlessly combine profound insights with captivating storytelling is truly impressive. It's like embarking on a thoughtfully curated journey through a vast universe of knowledge, designed to engage readers of all backgrounds. Your talent for making complex ideas accessible is truly outstanding. Furthermore, my intention is to share information on obtaining a Turkey eVisa specifically for Indian citizens. Delve into the simplified process of obtaining a Turkey evisa for Indians, offering convenient access to Turkey's rich cultural experiences, ensuring a stress-free travel experience.

    ReplyDelete