root@generate-random:~/api-keys/csharp$ _

Generate API Keys in C# (.NET)

Complete code tutorial with examples and best practices

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[ Code Example - Quick Summary ]

Language: C#

What: Generate cryptographically secure API keys in C# using <code>RandomNumberGenerator</code> for ASP.NET Core and .NET applications. Perfect for Web APIs and microservices.

Try it: Use our interactive Api-keys generator or integrate this code into your C# application.

Generate cryptographically secure API keys in C# using RandomNumberGenerator for ASP.NET Core and .NET applications. Perfect for Web APIs and microservices. Looking for other languages? Check our code examples in PHP , JavaScript , Python , Java , C++ , Ruby and Go or use our interactive web generator.

C# Code Example

using System;
using System.Security.Cryptography;

public class ApiKeyGenerator
{
    public static string GenerateApiKey(int length = 32)
    {
        using var rng = RandomNumberGenerator.Create();
        byte[] bytes = new byte[length];
        rng.GetBytes(bytes);

        // Convert to hexadecimal
        return BitConverter.ToString(bytes).Replace("-", "").ToLower();
    }

    public static string GenerateApiKeyBase64(int length = 32)
    {
        using var rng = RandomNumberGenerator.Create();
        byte[] bytes = new byte[length];
        rng.GetBytes(bytes);

        // Base64 URL-safe encoding
        return Convert.ToBase64String(bytes)
                      .Replace('+', '-')
                      .Replace('/', '_')
                      .TrimEnd('=');
    }

    public static void Main()
    {
        // Generate 256-bit (32 byte) API key
        string apiKey = GenerateApiKey(32);
        Console.WriteLine($"Hex: {apiKey}");
        // Output: "a7f3e9c2d8b4f1a6e5c9d7b3f8a2e6c4d9b5f7a3e8c6d2b9f4a7e1c5d8b3f6a9"

        string apiKeyBase64 = GenerateApiKeyBase64(32);
        Console.WriteLine($"Base64: {apiKeyBase64}");
        // Output: "p3_pwr2L8RpuXJbT-IouaztX86jG0rmU9KfhxdizNpo"
    }
}

[EXPLANATION]

C#'s RandomNumberGenerator class provides cryptographically secure random byte generation. The implementation properly disposes of the RNG with using statements. For .NET 6+, you can use RandomNumberGenerator.GetBytes() static method for cleaner code. The Base64 URL-safe encoding manually replaces special characters.

Expected Output

Hexadecimal: a7f3e9c2d8b4f1a6e5c9d7b3f8a2e6c4d9b5f7a3e8c6d2b9f4a7e1c5d8b3f6a9
Base64 URL-safe: p3_pwr2L8RpuXJbT-IouaztX86jG0rmU9KfhxdizNpo
.NET 6+ static: kL7mP9tR3wX6hY2jN8vB4qS1eC5fA9xD0pT7gU6iM3n