Xavier L. xhoong

TypeSafe Jev — Project Knowledge Resource

Status: Working project reference
Knowledge date: 16 September 2026
Scope: TypeSafe AI, System One Models, and specifically the Jev model

1. Purpose of this resource

Symmetic encryption

For symmetic encryption, you can use the following:

To encrypt:

openssl aes-256-cbc -salt -a -e -in plaintext.txt -out encrypted.txt

To decrypt:

Generate ssl certificates with Subject Alt Names on OSX

We can generate a common CA certificate, and then each project can use this CA certificate to sign and issue a project certificate. Hence the CA certificate is needed to install as a trusted cert, and once the project is signed and issue using this CA cert, the new project certificate will be trusted via chain of trust policy.

Generate a CA key

openssl genrsa -out ca.key 4096

Generate a CA public key, ensure expiry date is exceeding the individual cert

Open PostgreSQL and Create a table student in database student.

CREATE EXTENSION hstore;

CREATE TABLE student (
    id     int,
    name   varchar(254) NOT NULL,
    hobbies  text[],
    marks hstore
);

	#### Reference: https://raynix.info/archives/4296

	# in the master node, run as root
	kubeadm certs renew all
	[renew] Reading configuration from the cluster...
	[renew] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
	[renew] Error reading configuration from the Cluster. Falling back to default configuration

	certificate embedded in the kubeconfig file for the admin to use and for kubeadm itself renewed
	...

	FROM mcr.microsoft.com/mssql/server:2022-latest

	USER root

	RUN apt-get update && \
	apt-get install -y software-properties-common curl && \
	rm -rf /var/lib/apt/lists/*

	RUN curl https://packages.microsoft.com/keys/microsoft.asc \| apt-key add -
	RUN add-apt-repository "$(curl https://packages.microsoft.com/config/ubuntu/20.04/mssql-server-2022.list)"

	//https://softwaremill.com/comparing-scala-relational-database-access-libraries/
	case class MetroSystemWithCity(metroSystemName: String, cityName: String,
	dailyRidership: Int)

	implicit val getMetroSystemWithCityResult = GetResult(r =>
	MetroSystemWithCity(r.nextString, r.nextString, r.nextInt))

	val query = sql"""SELECT ms.name, c.name, ms.daily_ridership
	FROM metro_system as ms
	JOIN city AS c ON ms.city_id = c.id

	package com.softwaremill.akka

	import java.time._

	import akka.actor.ActorSystem
	import akka.stream.ActorMaterializer
	import akka.stream.scaladsl.Source

	import scala.collection.mutable
	import scala.concurrent.Await

	/**
	* Used for reading/writing to database, files, etc.
	* Code From the book "Beginning Scala"
	* http://www.amazon.com/Beginning-Scala-David-Pollak/dp/1430219890
	* http://stackoverflow.com/a/5218279
	*/
	def using[A <: {def close(): Unit}, B](param: A)(f: A => B): B =
	try { f(param) } finally { param.close() }

	def writeToFile(fileName:String, data:String) =