Tech Rescue

Hector Perez

How to generate 256-bit random hex strings in MacOS

The command openssl gives us everything we need. If you run openssl rand -hex 32 you will have an output like this: openssl rand -hex 32 fe2b27f8d12cc51729c6fcf43c8316b156eb86d539330ab8eb9b5641a5569df0 But what happens if we need more than one, say 20. We'll need to run seq 20 | xargs -n1 -I{} openssl rand -hex

Ethernet

Ethernet

What is Ethernet? Ethernet is the most common wired networking technology used in homes, offices, and data centers. It allows computers and other devices to communicate over a local area network (LAN) using cables and standardized protocols. Ethernet Cable Wiring Standards Ethernet cables use twisted pairs of wires to carry

IEEE-754

IEEE-754

Floating Point Made Simple! The IEEE-754 standard defines how computers represent floating point numbers — that is, numbers with decimals like 3.14 or -0.001. It helps ensure that all systems (computers, languages, CPUs) store and calculate with floating point numbers consistently. Why Do We Need IEEE-754? Computers use binary

AES GCM in .NET 8 (.csx script)

AES GCM in .NET 8 (.csx script)

Well, sooner or later, I would need a way to encrypt things, a safe way, therefore here I leave the code for AES GCM string encryption with .NET 8. I assume you already have .NET 8 installed as well as dotnet-script. #!/usr/bin/env dotnet-script /* ====================================================================== + AES-GCM (Galois/Counter Mode) -

AES Encryption Decryption Tool in .NET 8 (Console App)

AES Encryption Decryption Tool in .NET 8 (Console App)

Here is the code! copy it and paste it inside a file (say AESFileEncryptDecrypt.csx) and then run it with dotnet-script AESFileEncryptDecrypt.csx. I am assuming that you already have dotnet-script tool installed globally in your computer as well as .NET 8 SDK. In case you don't, you can install

JWE Generation & Verification in .NET 6

JWE Generation & Verification in .NET 6

This code is the result of a chat session with AI using codegemma:7b model. Generate JWE public static string GenerateJweToken(string issuer, string audience, SymmetricSecurityKey key, SigningCredentials credentials) { var claims = new[] { new Claim(JwtRegisteredClaimNames.Sub, "user_id"), new Claim(JwtRegisteredClaimNames.Name, "John Doe"), new Claim(JwtRegisteredClaimNames.Email, "john.doe@

JWT Generation & Verification with HMAC SHA-256 Signature in .NET 6

JWT Generation & Verification with HMAC SHA-256 Signature in .NET 6

This code is the result of a chat session with AI using deepseek-coder-v2-latest model. using System; using System.IdentityModel.Tokens.Jwt; using System.Security.Claims; using System.Text; using Microsoft.IdentityModel.Tokens; class Program { static void Main(string[] args) { // Define the security key and algorithm to sign the token var