Payment by NFC

- Sep 21, 2018-

NFC has appeared on mobile phones for 11 years. But even so, most people see NFC is still aggressive. As a playable and usable feature, NFC is very necessary to introduce it to everyone, whether it is used to replace various cards or as a chatter.

The first NFC-enabled mobile phone, the Nokia 6131, was released in 2006. The first NFC-enabled Android phone was the Nexus S released in 2010. At the end of 2012, the domestic flagship began to slowly carry NFC, the Apple camp was launched in the iPhone 6 in 2014, and the domestic services such as Apple Pay, Samsung Zhifu, Huawei/Millet payment started in 2016, which is regarded as NFC for many years. The largest application.

NFC's full name, Near Field Communication, evolved from RFID and interconnect technology and was jointly developed by Philips and Sony in 2003. In 2004, they and Nokia founded the NFC Forum Association to establish and promote NFC technology standards. Today, China Mobile, Huawei ZTE, Xiaomi Meizu, vivo, OPPO and other manufacturers are already members of the NFC Forum.

Technical characteristics and advantages: NFC works at 13.56MHz, the maximum transmission speed is only 424kbit/s, and the effective data transmission rate is only about 10cm (in fact, the NFC distance between bus cards and mobile phones is generally less than 5cm), but its advantage is The data can be read and exchanged directly without the need for a troublesome pairing process, which can be understood as an interconnection technique that uses the transmission distance to "change" power consumption and security. In addition, NFC also has a pairing speed, the pairing speed is less than 0.1ms (can improve experience and security), as contrast Bluetooth is about 6 seconds, infrared takes about 0.5 seconds.

The object to be read, such as the NFC tag, the bus card/access card, is driven by the electric power generated by the coil induction, so that the battery and the body size and weight can be made small. Even if it is working in a card reader, because the RF working distance is very short, the required power is very low, and the power consumption of the normally open is much lower than that of Bluetooth.

Hardware components: The NFC hardware part consists of three parts: CLF (non-connected front-end module), RF antenna, and SE (Secure Element security area). The common bus card balance reading can be done using the CLF+ antenna, and the SE part is required if the mobile phone/watch is modeled as a bus card (air card issuance and recharge). What we see outside is the structure of the chip + coil (opening the bus card and flash payment bank card, which are also the two basic components). The coils are usually mounted on the back shell or placed against the battery. Generally, the NFC is sensed through the back of the phone.

Working mode and use

NFC has three active modes: active, passive and two-way. It corresponds to the card reader in mobile phones and smart watches/wristles (such as mobile phone reading bus card balance), card simulation (such as mobile phone analog bus card, access card), P2P. (ie, point-to-point data transmission like Bluetooth) three working modes. Corresponding to the three working modes of NFC, the use of NFC, according to the scope of application from small to large, is roughly divided into the following three categories:

Two-way (P2P point-to-point data transmission mode): It is mainly point-to-point data transmission. The advantage is that the pairing can be done close to the distance, eliminating the need for password input. In the era of Android 4.0, Android Beam is added. The technical principle is to initialize the connection between the two mobile phones via NFC (NFC is basically responsible for transmitting the pairing information), and then transfer the URLs and contacts to each other. , pictures, music, video and other data and files, through the third-party app can complete wifi password, address and other types of data sharing.

Active (reader mode): NFC compatible with ISO7816-3 / ISO15693 / FeliCa (Sony proposed standard, more applications in Japan) PBC2.0 (People's Bank of China's second generation financial IC card specification, mainly used in bank cards On the top, the electronic account part of the flash payment card is such a standard, and can read the unencrypted balance of common bus cards, card-type one-time tickets, bank cards, access cards, campus cards and NFC tags. , transaction records and other information.

Samsung's S Beam is changed to Bluetooth transmission, although it can only be used between Samsung phones, but the speed is greatly improved. Another special usage is the common NFC pairing of products such as Sony cameras/speakers. It is also the transmission protocol and information transfer through NFC to complete fast and simple pairing. But the popularity of NFC is too low, and the communication software such as WeChat is powerful. This function has no practical value for 99% of domestic users.

99% of people don't know NFC knowledge! All in this science

The function of checking the balance of the bus card by mobile phone has already existed in 2012.

99% of people don't know NFC knowledge! All in this science

Passive (card emulation mode): As the name suggests, NFC emulation/disguise of a mobile phone/watch is a card of various NFC-compliant standards as mentioned above. This is also the most widely used and most used use in the entire NFC field, including the simulation of mobile phones/watches as access control cards, bus cards, UnionPay, Apple Pay, Samsung Zhifu, Huawei/Millet Pay. HCE flash payment (Android 4.4+NFC+ bank app is available) is one of the earlier, but the reputation is much smaller.

The NFC tags in the past have been on fire for a while, except for some early NFC phones that will distribute a few NFC tags that can be read and written by themselves. Some manufacturers even made smart products such as NFC rings. It is essentially an NFC plastic piece that records simple text messages such as URLs and numbers. It can be used to switch between the mode of switching phones, enabling certain functions, and opening URLs. For most people, the biggest use of this reader mode is to read the bus card balance.

Analog IC card or ID card

99% of people don't know NFC knowledge! All in this science

NFC Emulator access control card emulation app - NFC Emulator (the software charges higher and the actual limit is more)

Access cards can be roughly divided into IC card and ID card. Simple access card, mobile phone/watch can also read and NFC simulate its UID, it can replace the card. Complex access card, including UID, sector, keya/b, data and other data, the encrypted content can not be simulated. You can try to read the UID of the card with an app such as TagInfo.

Analog bus card

For convenience, in order to bring a physical card with less, we can choose to plug the physical card into the phone case, and even the high-end point can dismember the bus card, and then plug the chip and the coil into the phone case or the back cover (if the phone can still be opened The back cover)). There are a lot of smart products on the market, and a bus card is built in the form of a "shaped card".

99% of people don't know NFC knowledge! All in this science

In 2015, there were a number of products like the brush wristbands that support certain city bus cards, such as StarWrist smart watches, Wedge Sharkey smart watches, tiger fish watches and Industrial Bank's Xingpower payment bracelet (it also supports Flash payment), it is estimated that many people have never heard of it. The biggest disadvantage of these programs is that they need to buy an additional smart device. Secondly, in the environment where almost all major cities in China have their own bus cards, the bus cards between cities are not universal, which directly leads to the products of Lingnantong. , one card and other versions, and can not be used in the field of the other party.

The advantage of the NFC analog bus card is that the same device can be used to simulate the use of a bus card in different cities, or even a card such as an access card or a meal card, by replacing internal data, thereby completing the task of using one device in multiple cities. It is the simplest and essential difference between the two programs. But the most regrettable thing is that both programs have to open a bus card... 99% of people do not know the NFC knowledge! All in this science

Ticwatch 2 NFC after opening a virtual bus card

Opening time and cost: Huawei's bus card function was publicly tested at the end of August, and only supported Shanghai for the time being; Xiaomi Pay officially opened on September 1, claiming to support 34 cities, which is the largest number of support, but part of it. Marked cities and some models have not yet opened; Samsung Zhifu's bus card was officially launched in December 16 and temporarily only supports Beijing and Shanghai. At the beginning of the service opening, Samsung and Xiaomi had a subsidy of 1 yuan and free card opening, respectively. The current card opening fee is generally between 20-29 yuan.

In addition, one plus three in the hydrogen OS beta sixth edition system, also supports the Beijing card, it and Xiaomi use snowball technology program. Intelligent products support NFC analog bus cards, and now only Ticwatch 2 NFC (now only supports Beijing One Card and Shenzhen Tong), and the Huawei Watch 2 launched at the end of February may also be equipped. Samsung's Gear S3 series has been supported by Samsung Zhifu, but it has not yet opened a bus card service for it.

Recharge and inquiry: The bus cards simulated by these devices can be used to read balances and query transaction records through other NFC mobile phones, in addition to checking the balance and recharge on their own apps. "Peng Tao" and Beijing's "e music charge", and even Alipay's city card (but its compatibility problems are more) to recharge.

Restrictions and Uses: For the security considerations of bus card issuers and banks, bus cards and bank cards are bound to hardware, not user accounts. Once opened, the bus card is bound to the mobile phone body, and the bus card will be in place after the machine is flashed, but the bus card cannot be transferred to the new phone with the account after the change. The most regrettable is that no matter whether the physical card or the NFC analog card is adopted, the original bus card cannot be bound, and the new bus card can be re-opened, and the card is not supported.

Another "restriction" comes from the bus card itself. This kind of tool needs to work stably and quickly. When recharging and getting on the bus, it will erase the internal data, no need to connect to the network, no need for registration, and no report of loss. . It is like a banknote. If you lose it, you will lose it. No matter who you are, you can use it directly.

The use of bus cards is much more than everyone thinks. In addition to public transportation and subway, Beijing's parking lot / indoor park / gas station / part of the special store, Shanghai ferry, Suzhou's living payment / library / special merchants, Wuhan's airport express / ferry / special merchants, Hangzhou's roadside parking Guangzhou ferry/meter parking/special stores/partial supermarkets and convenience stores are all unpopular but have the same features.

UnionPay Flash Pay is a bank card-based contactless payment product launched by UnionPay, corresponding to Paywave of Foreign Visa and Paypass of MasterCard. It is characterized by a contactless and micropayment free password, which is as simple and convenient as a bus card. Nowadays, Apple Pay and other forms of flash payment are basically used by mobile phones instead of physical cards. The use process is to bind the bank card in the mobile phone, and use a small amount of confidentiality, fingerprint or regular password to consume the bank card with the flash payment.

NFC technology and product technical form

Technical route: Flash payment is a banking service after all, which has high requirements for security level. In the field of intelligent hardware, around security and NFC, Flash has two main technical routes: TSM and HCE. Their core is the SE security module mentioned in the above NFC science, which corresponds to the physical and virtual SE modules:

TSM: The full name of Trusted Service Manager trusted service management, which began to be large-scale and practical in 2014. For the early stage of Android with NFC but no SE security module, the manufacturer "opens the brain" through the SE security module and SIM card / The TF card and other integration methods allow mobile phones and smart devices to replace the physical card for flash payment. The early mobile phone "simulation" bus card mentioned above is also one of the products of this technology.

HEC: But TSM is a solution that requires hardware replacement. The actual implementation and impact are very limited. At about the same time, after Google added HEC (Host-Card Emulation Host Card Simulation) technical support for Android 4.4, UnionPay became the HCE flash payment in the middle and late 15 years, by using the cloud server as the SE module. (The origin of the "cloud" in the cloud flash payment), so that NFC mobile phones without security modules can use flash payment directly without hardware SE.

99% of people don't know NFC knowledge! All in this science

UnionPay flash has been developed for several generations in just a few years:

Early flash payment and even usage are very similar to bus cards. Users need to go to the bank/ATM to deposit funds into the electronic cash account.

Later, in order to save the process of the deposit, the flash payment was merged into the bank account;

Later, in order to save the trouble of carrying the card, the two technical paths of TSM and HEC mentioned above were derived. The NFC-SIM and NFC-SD card equipped with the security chip introduced by UnionPay are designed to enable the flash payment function of the NFC mobile phone without the SE module.