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Plug n Trust click

‍Plug&Trust Click is a compact add-on board that contains a ready-to-use IoT secure element solution.

click Product page

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Click library

• Author : Luka Filipovic
• Date : Feb 2021.
• Type : I2C type

Software Support

We provide a library for the PlugnTrust Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on mikroE github account.

Library Description

‍This library contains API for PlugnTrust Click driver.

Standard key functions :

• plugntrust_cfg_setup Config Object Initialization function.

  void plugntrust_cfg_setup ( plugntrust_cfg_t *cfg );

• plugntrust_init Initialization function.

  err_t plugntrust_init ( plugntrust_t *ctx, plugntrust_cfg_t *cfg );

• plugntrust_default_cfg Click Default Configuration function.

  err_t plugntrust_default_cfg ( plugntrust_t *ctx );

Example key functions :

• plugntrust_apdu_transfer Write-Read frame data function.

  err_t plugntrust_apdu_transfer ( plugntrust_t *ctx, plugntrust_frame_data_t *frame_data );

• plugntrust_select_card_manager Select card manager.

  err_t plugntrust_select_card_manager ( plugntrust_t *ctx, uint8_t rsp, uint8_t *cardmanager_rsp, uint8_t *cardmanager_rsp_len );

• plugntrust_select_applet Selects Clicks Applet and returns info that device sends back to host.

  err_t plugntrust_select_applet ( plugntrust_t *ctx, uint8_t ns_encode, plugntrust_version_info_t *ver_info );

Example Description

‍This application is showcasing basic functionality of Plug&Trust

click board. It gets identify data from device, selects card manager and applet. Then checks free memory, reads all objects and deletes not reserved ones. After that showcases a few of functionality: Generating random data, Creating, reading and deleteing binary objects, Creating AES symmetrical key and cipher with it; In the end it is showcasing funcionality in the endless loop.

The demo application is composed of two sections :

Application Init

‍At the start it sets comunication interface from default

configuration[I2C]. Reads indetifing data from device, and then selects Card manager and applet. After that it reads free presistant memory, reads all objects and deletes objects that are not reserved by the Applet. Then it generates 2 byte of random data, and gets the version information from the Applet. Thtas followed up with creating binary object and 'MikroE' data is wrriten in it. Then its checked it object is created, and reads data back, in the end its deleted and checked if it still exists. Finally it creates 128AES key (16bytes), and then it encrypts and then decrypts data with that key, and in the end it deletes that key object.

void application_init ( void ) 
{
    log_cfg_t log_cfg;  
    plugntrust_cfg_t plugntrust_cfg;  
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, " Application Init " );
    // Click initialization.
    plugntrust_cfg_setup( &plugntrust_cfg );
    PLUGNTRUST_MAP_MIKROBUS( plugntrust_cfg, MIKROBUS_1 );
    err_t init_flag = plugntrust_init( &plugntrust, &plugntrust_cfg );
    if ( init_flag == I2C_MASTER_ERROR ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
 
        for ( ; ; );
    } 
    
    frame_data.apdu = &apdu_data;
    
    plugntrust_default_cfg ( &plugntrust );
    
    if ( PLUGNTRUST_INTERFACE_ISO14443 == plugntrust.interface )
    {
        log_info( &logger, " ISO14443 Interface active..." );
        for ( ; ; );
    }
    
    soft_reset( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    get_data_identify( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    select_card_manger( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    select_applet( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    check_free_memory( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    list_and_delete_objects( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    get_random( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    read_uid_object( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    get_version(  );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    create_check_delete( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    aes_cipher( );
    
    log_info( &logger, " Application Task " );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

Application Task

‍It generates 16bytes of data, writes it in binary object and

then reads it and logs it. Then creates AES key and encrypts that random data with it, and then decrypts it. In the end it deletes both AES key object and binary object thats created at the start of task.

void application_task ( void ) 
{
    #define DATA_LEN 16
    static uint8_t aes_value[ DATA_LEN ]    = { 0x40, 0x41, 0x42, 0x43,0x44, 0x45, 0x46, 0x47,
                                                0x48, 0x49, 0x4A, 0x4B,0x4C, 0x4D, 0x4E, 0x4F };
    static uint32_t binary_id               = 0xBBBBBBBBul;
    static uint32_t aes_id                  = 0xCCCCCCCCul;
    uint8_t random_data[ DATA_LEN ]         = { 0 };
    uint8_t read_data[ DATA_LEN ]           = { 0 };
    uint8_t encrypted_data[ DATA_LEN ]      = { 0 };
    uint32_t read_len = DATA_LEN;
    
    if ( PLUGNTRUST_OK == plugntrust_get_random_numbers( &plugntrust, random_data, DATA_LEN ) )
    {
        log_printf( &logger, " > Generated random data: 0x" );
        log_buf_hex( random_data, DATA_LEN );
        log_printf( &logger, "\r\n" );
    }
    else
    {
        log_error( &logger, " Random" );
    }
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    if ( PLUGNTRUST_OBJECT_DOESNT_EXIST == plugntrust_check_object_exist( &plugntrust, binary_id ) )
    {
        log_printf( &logger, " Write random data to binary object...\r\n" );
        if ( PLUGNTRUST_OK != plugntrust_write_binary_object( &plugntrust, binary_id, 0, DATA_LEN, random_data ) )
        {
            log_error( &logger, " Write Binary" );
        }
        else
        {
            log_info( &logger, " Status OK" );
        }
    }
    else
    {
        log_error( &logger, " Binary object already exist" );
    }
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    if ( PLUGNTRUST_OBJECT_DOES_EXISTS == plugntrust_check_object_exist( &plugntrust, binary_id ) )
    {
        if ( PLUGNTRUST_OK == plugntrust_read_object( &plugntrust, binary_id, 0, 0, read_data, &read_len ) )
        {
            log_printf( &logger, " > Read data from binary object: 0x" );
            log_buf_hex( read_data, read_len );
            log_printf( &logger, "\r\n" );
        }
        else
        {
            log_error( &logger, " Read binray object" );
        } 
    }
    else
    {
        log_error( &logger, " Binary object doesn't exist" );
    }
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    log_printf( &logger, " Create AES key...\r\n" );
    create_128_aes_key( aes_id, aes_value );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    if ( PLUGNTRUST_OK == cipher_data_with_aes_key( aes_id, PLUGNTRUST_P2_ENCRYPT_ONESHOT, read_data, encrypted_data ) )
    {
        log_printf( &logger, " > Encrypted data: 0x" );
        log_buf_hex( encrypted_data, DATA_LEN );
        log_printf( &logger, "\r\n" );
    }
    else
    {
        log_error( &logger, " Encrypting data" );
    }
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    if ( PLUGNTRUST_OK == cipher_data_with_aes_key( aes_id, PLUGNTRUST_P2_DECRYPT_ONESHOT, encrypted_data, read_data ) )
    {
        log_printf( &logger, " > Decrypted data: 0x" );
        log_buf_hex( read_data, DATA_LEN );
        log_printf( &logger, "\r\n" );
    }
    else
    {
        log_error( &logger, " Decrypting data" );
    }
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    log_printf( &logger, " Delete Binary and AES object...\r\n" );
    if ( ( PLUGNTRUST_OK != plugntrust_delete_object( &plugntrust, binary_id ) ) || ( PLUGNTRUST_OK != plugntrust_delete_object( &plugntrust, aes_id ) ) )
    {
        log_error( &logger, " Deleting objects" );
    }
    log_printf( &logger, "*****************************************************************************\r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

Note

‍For more informations and explanations refer to documents

from NXP->AN12413 and UM11225.

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on mikroE github account.

Other mikroE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.PlugnTrust

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all Mikroelektronika compilers.

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