FreeOTP app for two factor authentication

Github has an option to add a second factor for authentication. However, whilst at it, I found Google Authenticator, Microsoft Authenticator, Authy to be quite bloated and feature-full compared to the simple purpose of generating an OTP. I found that one of the simplest was FreeOTP available at https://play.google.com/store/apps/details?id=org.fedorahosted.freeotp for Android devices and for others … Continue reading FreeOTP app for two factor authentication

How to convert PostScript script to a .ps file for viewing in PDF viewer or to PNG

Reading about Gerard Huet's paper on the geometry of the Shri Yantra available in PDF format at this link http://pauillac.inria.fr/~huet/SKT/sanskrit.html.orig, I was prompted to try out the Postscript code he had in and Appendix in the paper. After typing the code into a .txt file, the file did not render using Evince or a PDF … Continue reading How to convert PostScript script to a .ps file for viewing in PDF viewer or to PNG

How to securely wipe a hard drive or USB drive in Linux using dd or scrub

Normally we'd use dd to clean wipe a hard drive as follows after opening a terminal window for a hard disk or USB drive accessible as /dev/sdb :$ sudo dd if=/dev/urandom of=/dev/sdb status=progress <enter> Another command to do a secure wipe of /dev/sdb is scrub that can be used as follows:$ sudo scrub -p dod … Continue reading How to securely wipe a hard drive or USB drive in Linux using dd or scrub

Email: [Firebase] Client access to your Cloud Firestore database expiring in X day(s)

The easiest way to overcome this expiry is to change the date in the rules after logging into the account:match /{document=**} {// from previous date 2020, 11, 11 to new date 2021, 12, 11allow read, write: if request.time < timestamp.date(2021, 12, 11);} However, do note that it is important to drop access using this method … Continue reading Email: [Firebase] Client access to your Cloud Firestore database expiring in X day(s)

How to check if user name or ID has been compromised in a data breach

When data breaches occur, there are various kinds of data that get compromised. The most critical data that can get compromised is the user name or ID or the password. All is not lost due to a great service hosted by Troy Hunt. Use https://haveibeenpwned.com/ to check if the User name or user ID appears … Continue reading How to check if user name or ID has been compromised in a data breach

Remember History in Firefox 75+ and private browser windows

Mozilla Firefox 75+ has made a change in the way it determines whether web sites open in a private window or not. This is now tied in with the "Remember History" option in Preferences -> Privacy and Security option. To enable Private Windows all the time, select "Never Remember History", but to disable private windows, … Continue reading Remember History in Firefox 75+ and private browser windows

Recover encrypted ecryptfs home folder from encrypted dm-crypt luks disk volume

Whew... saved by the skin of teeth. The grub2 bootloader of my computer got corrupt. I was not able to boot into the computer and all was lost. For security reasons, I set up LVM with full disk encryption. Thereafter, each user's home folder was further encrypted with ecryptfs (the default you get when you … Continue reading Recover encrypted ecryptfs home folder from encrypted dm-crypt luks disk volume

How to disable user list and guest user login in Ubuntu 16.04 LTS

To disable the user list and guest user login in Ubuntu 16.04 LTS login screen, open a terminal window and do the following: $ cd /etc/lightdm <enter> $ sudo mkdir lightdm.conf.d <enter> $ sudo cd lightdm.conf.d <enter> $ sudo mousepad 50-config.conf <enter> Enter the text below into the file. [SeatDefaults] greeter-hide-users=true greeter-show-manual-login=true allow-guest=false Save the … Continue reading How to disable user list and guest user login in Ubuntu 16.04 LTS

How to calculate MD5 or SHA256 sums in Linux and Android

Many of us use Linux Distributions like Ubuntu, Fedora, available for free on the Internet. To install these distributions on our computers, we need to down their ISO files. Recently, the Linux Mint ISO was hacked and malware inserted into some of it's files. It was then repacked and put up on an external website. … Continue reading How to calculate MD5 or SHA256 sums in Linux and Android