NfcReaderLib 1.0.3

NfcReaderLib

Low-level NFC/Smart card utilities library providing platform-independent PC/SC communication, SL Token generation, and utility functions for card data processing.

? What's New in v1.0.2

• ?? Platform-Independent Wrapper - Automatic 32-bit/64-bit detection
• ?? Unified API - Single codebase for both platforms
• ?? Enhanced PC/SC Support - ModWinsCard, ModWinsCard32, ModWinsCard64
• ?? Improved Documentation - Complete guides and examples
• ?? NuGet Publishing - Easy updates with GitHub Actions

?? Installation

Package Manager Console

Install-Package NfcReaderLib -Version 1.0.2

.NET CLI

dotnet add package NfcReaderLib --version 1.0.2

PackageReference

<PackageReference Include="NfcReaderLib" Version="1.0.2" />

?? Target Framework

• .NET Framework 4.7.2

Compatible with:

• .NET Framework 4.7.2+
• .NET Standard 2.0+
• .NET Core 2.0+
• .NET 5+

Platforms: Windows (32-bit and 64-bit automatically detected)

?? Features

Core Functionality

• ?? Platform-Independent PC/SC - Automatic 32/64-bit detection
• ?? SL Token Generation - SHA-256 based secure tokens from ICC certificates
• ?? Card Utilities - Helper functions for card data processing
• ?? Data Formatting - Byte array and hex string conversions
• ??? EMV Support - ICC certificate parsing and validation
• ?? Cryptography - SHA-256 hashing utilities

Platform Support

• ? Windows 32-bit - Full support via ModWinsCard32
• ? Windows 64-bit - Full support via ModWinsCard64
• ? Auto-Detection - Use ModWinsCard wrapper for automatic platform selection
• ? IntPtr Handles - Platform-appropriate handle sizes

?? Quick Start

Platform-Independent PC/SC Communication

using NfcReaderLib;

// ModWinsCard automatically detects 32-bit or 64-bit platform
IntPtr hContext = IntPtr.Zero;
int result = ModWinsCard.SCardEstablishContext(
    ModWinsCard.SCARD_SCOPE_USER, 0, 0, ref hContext);

if (result == ModWinsCard.SCARD_S_SUCCESS)
{
    Console.WriteLine($"Running on {ModWinsCard.GetPlatformInfo()} platform");
    
    // List readers
    int pcchReaders = 0;
    ModWinsCard.SCardListReaders(hContext, null, null, ref pcchReaders);
    
    byte[] readers = new byte[pcchReaders];
    ModWinsCard.SCardListReaders(hContext, null, readers, ref pcchReaders);
    
    // Release context
    ModWinsCard.SCardReleaseContext(hContext);
}

SL Token Generation

using NfcReaderLib;

// Generate SL Token from ICC certificate
var slCard = new SLCard
{
    PAN = "1234567890123456",
    AID = "A0000000031010",
    IccPublicKeyCertificate = iccCertData
};

string token = slCard.GetSLToken();      // No spaces: "E3B0C442..."
string token2 = slCard.GetSLToken2();    // With spaces: "E3 B0 C4 42..."

Utility Functions

// Hex conversions
byte[] data = Util.FromHexString("9F 46 01 02 03");
string hex = Util.ByteArrayToHexString(data);

// PAN masking
string masked = Util.MaskPAN("1234567890123456");
// Output: "1234 56** **** 3456"

// SHA-256 hash
byte[] hash = Util.CalculateSHA1(data);

?? Main Classes

ModWinsCard (Platform-Independent Wrapper) ? NEW

Purpose: Automatic 32-bit/64-bit platform detection for PC/SC operations

Key Features:

• ?? Automatic platform detection using IntPtr.Size
• ?? Single API for both 32-bit and 64-bit Windows
• ? Type-safe with IntPtr handles
• ? Zero performance overhead

Example:

// Check platform
bool is64Bit = ModWinsCard.IsRunning64Bit();
string platform = ModWinsCard.GetPlatformInfo(); // "32-bit" or "64-bit"

// Establish context (works on both platforms)
IntPtr hContext = IntPtr.Zero;
int result = ModWinsCard.SCardEstablishContext(
    ModWinsCard.SCARD_SCOPE_USER, 0, 0, ref hContext);

Methods:

• Context Management: SCardEstablishContext, SCardReleaseContext
• Reader Operations: SCardListReaders, SCardConnect, SCardDisconnect
• Card Operations: SCardStatus, SCardTransmit, SCardBeginTransaction
• Error Handling: GetScardErrMsg(int returnCode)
• Platform Info: IsRunning64Bit(), GetPlatformInfo()

See also: Platform Wrapper Documentation

SLCard

Purpose: Card model with ICC certificate parsing and SL Token generation

Properties:

• PAN - Primary Account Number
• AID - Application Identifier
• IccPublicKeyCertificate - ICC certificate data (Tag 9F46)
• IccPublicKeyExponent - ICC exponent (Tag 9F47)
• IccPublicKeyRemainder - ICC remainder (Tag 9F48)
• IssuerPublicKeyCertificate - Issuer certificate (Tag 90)
• IssuerPublicKeyExponent - Issuer exponent (Tag 9F32)
• IssuerPublicKeyRemainder - Issuer remainder (Tag 92)

Methods:

• GetSLToken() - Generate SHA-256 based SL Token (no spaces)
• GetSLToken2() - Generate SHA-256 based SL Token (space-separated hex)
• GetMaskedPAN() - Get masked PAN for privacy
• ParseIccPublicKey(EmvPublicKey issuerKey) - Parse ICC certificate (EMV v4.3)

Example:

var slCard = new SLCard
{
    PAN = "1234567890123456",
    AID = "A0000000031010",
    IccPublicKeyCertificate = certificateBytes
};

string token = slCard.GetSLToken2();
// Output: "E3 B0 C4 42 98 FC 1C 14 ... 52 B8 55" (64 hex bytes)

string maskedPan = slCard.GetMaskedPAN();
// Output: "1234 56** **** 3456"

Util

Purpose: Utility functions for data conversion and formatting

Key Methods:

Hex Conversions:

• FromHexString(string hex) - Convert hex string to byte array
• ByteArrayToHexString(byte[] bytes) - Convert byte array to hex string
• PrettyPrintHex(byte[] data) - Format as space-separated hex

PAN Masking:

• MaskPAN(string pan) - Mask card number for privacy
• MaskCardNumber(string cardNumber, string mask) - Custom masking

Cryptography:

• CalculateSHA1(byte[] data) - SHA-256 hash (note: legacy name)

Data Conversion:

• ByteToInt(byte b) - Convert byte to integer
• Byte2Short(byte b1, byte b2) - Convert two bytes to short
• HexToAscii(string hexStr) - Convert hex string to ASCII
• NotEmpty(byte[] bytearray) - Check if array has data

?? Platform-Independent Architecture

How It Works

Your Application
       ?
  ModWinsCard (Wrapper)
       ?
   [Platform Detection: IntPtr.Size == 8?]
       ?
  ???????????
  ?         ?
64-bit    32-bit
(Int64)   (int)
  ?         ?
winscard.dll

Benefits

? Single Codebase - Write once, run on both platforms
? Automatic Detection - No configuration needed
? Type Safe - IntPtr ensures correct handle sizes
? Zero Overhead - Simple delegation pattern
? Backward Compatible - Platform-specific classes still available

Migration Example

Before (64-bit only):

Int64 hContext = 0;
ModWinsCard64.SCardEstablishContext(
    ModWinsCard64.SCARD_SCOPE_USER, 0, 0, ref hContext);

After (Platform-independent):

IntPtr hContext = IntPtr.Zero;
ModWinsCard.SCardEstablishContext(
    ModWinsCard.SCARD_SCOPE_USER, 0, 0, ref hContext);

See: Migration Guide

?? SL Token Details

What is SL Token?

The SL (Secure Link) Token is a unique cryptographic identifier derived from the card's ICC Public Key Certificate using SHA-256 hashing.

How It Works

ICC Certificate (Tag 9F46) ? SHA-256 Hash ? Space-Separated Hex ? SL Token

Example:

Input:  ICC Certificate (128-248 bytes)
Output: "E3 B0 C4 42 98 FC 1C 14 9A FB F4 C8 99 6F B9 24 27 AE 41 E4 64 9B 93 4C A4 95 99 1B 78 52 B8 55"

Properties

?? Unique - Each card generates a unique token
?? Consistent - Same card always produces the same token
?? Secure - One-way hash, cannot be reversed
??? Privacy-Friendly - No PAN or sensitive data exposed
?? Format - 64 bytes as space-separated hex (191 characters)

Use Cases

• ?? Loyalty program card identification
• ?? Card binding to user accounts
• ?? Transaction correlation
• ?? Duplicate card detection
• ?? Analytics without storing sensitive data

?? Advanced Usage

EMV Certificate Parsing

using NfcReaderLib;

var slCard = new SLCard
{
    PAN = "1234567890123456",
    AID = "A0000000031010",
    IccPublicKeyCertificate = iccCert,
    IccPublicKeyExponent = iccExp,
    IccPublicKeyRemainder = iccRem
};

// Parse ICC public key (requires issuer public key)
var issuerKey = new SLCard.EmvPublicKey(issuerModulus, issuerExponent);
var iccKey = slCard.ParseIccPublicKey(issuerKey);

if (iccKey != null)
{
    Console.WriteLine($"ICC Key: {iccKey}");
}

Custom Hex Formatting

byte[] data = new byte[] { 0x9F, 0x46, 0x01, 0x02 };

// Standard hex string (no spaces)
string standard = Util.ByteArrayToHexString(data); // "9F460102"

// Pretty print (with spaces)
string pretty = Util.PrettyPrintHex(data); // "9F 46 01 02"

// Parse back
byte[] parsed = Util.FromHexString(pretty);

Platform Detection

// Check current platform
if (ModWinsCard.IsRunning64Bit())
{
    Console.WriteLine("Running on 64-bit Windows");
}
else
{
    Console.WriteLine("Running on 32-bit Windows");
}

// Or get string
Console.WriteLine($"Platform: {ModWinsCard.GetPlatformInfo()}");

?? Dependencies

• System.Security.Cryptography.Algorithms (v4.3.1) - SHA-256 hashing

?? Requirements

• .NET Framework 4.7.2 or later
• Windows 7 or later (for PC/SC support)
• PC/SC smart card reader (for card operations)

?? Documentation

Included Documentation

• README_ModWinsCard.md - Platform wrapper guide
• MIGRATION_SUMMARY.md - Migration details
• QUICKSTART_NUGET.md - Publishing guide

Online Resources

• GitHub Repository
• NuGet Package
• Issues & Support

?? Related Packages

• EMVCard.Core - High-level EMV card reading library (depends on NfcReaderLib)

?? Contributing

We welcome contributions! See the repository for contribution guidelines.

Publishing to NuGet

This package uses environment variables for secure NuGet publishing:

# Set API key
$env:NUGET_API_KEY = "your-key-here"

# Publish
./publish-nuget.ps1

See: Publishing Guide

?? License

Copyright � Johan Henningsson 2026

This project is licensed under the MIT License.

????? Author

Johan Henningsson

• GitHub: @johanhenningsson4-hash
• Repository: EMVReaderSL

?? Acknowledgments

• EMV specifications by EMVCo
• PC/SC Workgroup
• .NET Cryptography API
• Contributors and users of this library

?? Version History

v1.0.2 (Latest)

• ? Added platform-independent wrapper (ModWinsCard)
• ? Automatic 32-bit/64-bit detection
• ? Updated EmvCardReader to use IntPtr
• ?? Enhanced documentation with guides
• ?? Added NuGet publishing workflow
• ?? Added security features (Git hooks, .gitignore)

v1.0.1

• ?? Updated copyright to 2026
• ?? Improved documentation
• No functional changes

v1.0.0

• ?? Initial release
• ?? SL Token generation
• ?? Card utilities
• ?? Cryptography helpers

Made with ?? by Johan Henningsson | 2008-2026

? Star this package on GitHub if you find it useful!