Skip to main content

All numbers are random, but some are more random than others

This title is an adaption of the quote from George Orwell's book Animal Farm:

All animals are equal, but some are more equal than others

So what is this post all about? During a code review I noticed the following code to create a random number in C#:

This code will return an integer between -1 and 2147483647. There is nothing wrong with this code until you know the context where it is used. Using System.Random is a performant easy way to get random values, but this implementation is not truly random. System.Random uses a seed to generate values from. The same seed will produce the same order of values. And similar seeds will produce similar values. This could lead to vulnerabilities a bad actor can use.

So we need a better solution…

Luckily a cryptographic safe alternative is provided in the form of the RandomNumberGenerator class:

In the example above a new byte array of length 16 is created that will contain 16 random bytes. You can convert this yourself to an integer but you can also use the GetInt32() method instead:

Labels:

Popular posts from this blog

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.
Read more

Kubernetes–Limit your environmental impact

Reducing the carbon footprint and CO2 emission of our (cloud) workloads, is a responsibility of all of us. If you are running a Kubernetes cluster, have a look at Kube-Green . kube-green is a simple Kubernetes operator that automatically shuts down (some of) your pods when you don't need them. A single pod produces about 11 Kg CO2eq per year( here the calculation). Reason enough to give it a try! Installing kube-green in your cluster The easiest way to install the operator in your cluster is through kubectl. We first need to install a cert-manager: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml Remark: Wait a minute before you continue as it can take some time before the cert-manager is up & running inside your cluster. Now we can install the kube-green operator: kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml Now in the namespace where we want t...
Read more

DevToys–A swiss army knife for developers

As a developer there are a lot of small tasks you need to do as part of your coding, debugging and testing activities.  DevToys is an offline windows app that tries to help you with these tasks. Instead of using different websites you get a fully offline experience offering help for a large list of tasks. Many tools are available. Here is the current list: Converters JSON <> YAML Timestamp Number Base Cron Parser Encoders / Decoders HTML URL Base64 Text & Image GZip JWT Decoder Formatters JSON SQL XML Generators Hash (MD5, SHA1, SHA256, SHA512) UUID 1 and 4 Lorem Ipsum Checksum Text Escape / Unescape Inspector & Case Converter Regex Tester Text Comparer XML Validator Markdown Preview Graphic Col...
Read more