APDU Sender Contactless

APDU Sender Contactless is an application designed for the Android platform that enables users to send ISO7816-4 C-APDU commands via NFC technology. This app facilitates the interaction with contactless smart cards by allowing users to send commands and receive responses wirelessly. Those interested in experimenting with smart card communication can download APDU Sender Contactless to explore its various functionalities.

The application provides a user-friendly interface where users can construct a C-APDU command using a structured layout. The command includes several parameters: CLA (Class byte), INS (Instruction byte), P1 and P2 (Parameter bytes), Lc (Length of the command data), Data (the command data itself), and Le (Expected length of the response). This layout aids users in creating commands tailored to their specific needs.

In addition to the structured approach, APDU Sender Contactless also supports sending C-APDU commands in raw format. This feature allows for greater flexibility, as users can input any data they desire without adhering to the predefined layout. This capability is particularly useful for advanced users who may need to send unique commands not covered by the standard layout.

For those who prefer using predefined commands, the app includes a built-in command list. This list consists of various commonly used commands, including selecting application identifiers such as SELECT PSE, SELECT PPSE, SELECT VISA AID, and SELECT MASTERCARD AID, among others. Users can quickly access these commands, making it easier to interact with different types of smart cards.

The app also includes commands for reading records from the card, such as READ RECORD SFI:01 R:01 and READ RECORD SFI:02 R:01. These commands enable users to retrieve specific information stored on the card, which can be valuable for applications requiring card data access. Additionally, commands such as GET ATC (Application Transaction Counter) and GET PIN TRY COUNTER provide insights into the state of the card, enhancing user understanding of its usage.

Another aspect of APDU Sender Contactless is its TLV (Tag-Length-Value) response interpretation feature. This function allows users to decode the responses received from their smart cards. By interpreting the responses with relevant EMV tags and ISO7816 Status Words, users can better understand the data being returned and the status of their commands. This feature is particularly beneficial for those involved in payment processing or smart card development.

User engagement is further supported by the app's educational focus. It is distributed with the intention of being a useful tool for learning about NFC technology and smart card communication. This educational aspect makes it an attractive resource for both hobbyists and professionals interested in exploring the capabilities of contactless smart cards.

The source code for APDU Sender Contactless is available on GitHub, allowing developers to examine the underlying architecture of the application. This transparency promotes collaboration and enables users to modify or extend the app according to their needs. By providing access to the source code, the application fosters a community of developers who can contribute to its improvement.

For those who are interested in using NFC technology and smart card capabilities, downloading APDU Sender Contactless offers a practical and comprehensive solution. The app's combination of structured command input, raw command capabilities, predefined command lists, and response interpretation makes it a versatile tool for interacting with contactless cards. Users can engage with a variety of smart card applications, gaining insights into the data contained within and the commands that govern their operation.

With its focus on educational purposes, the app serves as a resource for both new and experienced users. The blend of user-friendly features and advanced command options ensures that individuals can explore the depths of NFC interactions, whether for personal projects or professional development.

APDU Sender Contactless stands out as a valuable application in the realm of NFC technology and contactless smart card communication. The ability to send and interpret commands effectively allows users to gain practical experience and understanding of how smart cards operate. This application represents a significant step towards enabling users to harness the potential of contactless technology in various applications.

For further exploration of its capabilities and features, users can visit the source code repository on GitHub at https://github.com/jmarroyo/ApduSenderContactLess.