KNM.CryptoHelper

Description

KNM.CryptoHelper is a production-ready C# cryptographic library for enterprise .NET applications. Provides AES-256 encryption with HMAC integrity, JWT authentication, TOTP MFA, device fingerprinting, and OTP generation. Full DI integration with fluent configuration.

Installation

Single NuGet package - Zero dependencies!

Install-Package KNM.CryptoHelper

Bundled: OtpNet, QRCoder, UAParser, System.IdentityModel.Tokens.Jwt ✅

Quick Start

1. Dependency Injection (Recommended)

builder.Services.AddKnmCryptoCollection(options =>
{
    options.Crypto.CryptoPassword = "YourSecurePassword!";
    options.DeviceFingerprint.CacheExpiryDays = 30;
    options.Otp.Length = 6;
});

2. Fluent Builder

builder.Services.AddKnmCryptoCollection()
    .WithCrypto(crypto => crypto.Iterations = 200_000)
    .WithOtp(opt => opt.Length = 6)
    .WithDeviceFingerprint(opt => opt.CacheExpiryDays = 7);

Core Features

🔐 AES Encryption + HMAC Integrity

string encrypted = crypto.EncryptText("Secret data");
string decrypted = crypto.DecryptText(encrypted); // Tamper-proof

🪪 Device Fingerprinting + Trusted Devices

await crypto.InjectDeviceContextAsync(context, userId); // Sets MFARequired
var deviceInfo = crypto.GetDeviceInfo(context, userId);
string fp = crypto.GenerateDeviceFingerprint(context);

📱 OTP Generation

var otp = crypto.GenerateOtp(); // OtpResult(Code="592134", ExpiryDate)

🔑 JWT Tokens

string jwt = crypto.GenerateJwtToken(userId, email, claims);
bool isValid = crypto.JwtTokenIsValid(jwt).isValid;

🔐 TOTP MFA (QR + Verify)

string secret = crypto.GenerateMfaSecret();
string qrSvg = crypto.GenerateMfaQrCode("user@company.com", secret);
bool valid = crypto.VerifyMfaCode(secret, "123456");

Technical Stack

Enterprise Features

• Fluent configuration with validation
• IMemoryCache integration for trusted devices
• Swagger compatible middleware
• .NET 10 + MAUI ready
• Zero external deps - Everything bundled!

Configuration Example

builder.Services.AddKnmCryptoCollection()
    .WithCrypto(opt => opt.Iterations = 100_000)
    .WithOtp(opt => 
    {
        opt.Length = 5;
        opt.ValidityDurationMinutes = 5;
    })
    .WithDeviceFingerprint(opt => 
    {
        opt.SimilarityThreshold = 0.92;
        opt.CacheExpiryDays = 30;
    });

Production crypto made simple - One package, full security suite! 🚀