The MIFARE Classic family covers contactless smart card ICs used in public transport, access management, loyalty cards and many more. 
Fully compliant with ISO/IEC 14443 Type A, it is available with  4 KB memory, and 7 byte or 4 byte identifiers.
Key features and benefits
>Fully ISO/IEC 14443Type A 1-3 compliant, ensuring a broad marketplace of solution developers and providers
> Available with 7 byte unique identifier (7B UID) or 4 byte non-unique identifier (4B NUID)
> Versatile product portfolio, offering an optimized price-performance ratio
> 4 KB EEPROM
> Reduced infrastructure costs due to card and reader compatibility across all generations
> Memory access conditions freely programmable
> Many companies with commercial products, enabling a broad and competitive supply chain
>Personalization options supporting flexibility within 4 byte- and 7 byte UID infrastructure (7B UID version only)
> Fast time-to-market
Key applications
> Public transportation
> Electronic toll collection
> Loyalty cards
> Event ticketing
> Car parking

Make contactless cards Alipay for instance, it is about many manufacturers from the industrial chain, for example mobile phone manufacturers, mobile operators, bus corporation, bank, union pay and the like. Each one of these make commercial mode complicated meanwhile, they have got limited the short development. In terms of the unsafe application, the cultivation of users' habit along with the popularization of NFC mobile phone are a couple of challenges.