Computer Tips - Programming, Cybersecurity and Tech Tutorials

I was working on a python3 script on my macOS, and I came across this error: % python3 my-random-script.py Unable to revert mtime: /Library/Fonts I got it solved by installing libmagic: % brew install libmagic This message on macOS comes from the python-magic library when its underlying libmagic dependency is missing. The script still runs but cannot read file type information and prints this warning. Installing libmagic with Homebrew, as shown, supplies the missing piece and clears the message. python-magic relies on the same system libmagic that the file command uses.

NTRU: NTRU – Nth Degree Truncated Polynomial Ring Units (or R = Z[X] / ( X^N-1 )) NTRU is the first public-key cryptosystem not based on factorization or discrete logarithmic problems. NTRU is a lattice-based alternative to RSA and ECC and is based on the shortest vector problem in a lattice. NTRU is an open-source public-key cryptosystem that uses lattice-based cryptography to encrypt and decrypt data. It consists of two algorithms: NTRUEncrypt, which is used for encryption, and NTRUSign, which is used for digital signatures. Unlike other popular public-key cryptosystems, it is resistant to attacks using Shor's algorithm. NTRUEncrypt was patented, but it was placed in the public domain in 2017. NTRUSign is patented, but it can be used by software under the GPL. Example in Python3: % python3 --version Python 3.9.1 % pip3 install --user sympy % pip3 install --user numpy % pip3 install --user docopt

Google Photos is a photo-sharing and storage service developed by Google . It was announced in May 2015 and separated from Google+, the company's former social network. In its free tier, Google Photos stores unlimited photos and videos up to 16 megapixels and 1080p resolution, respectively (anything larger gets down-scaled to these sizes). This free tier will end on June 1, 2021 . Photos and videos uploaded after that date get counted towards the 15 GB free quota shared across the user's Google services . There are subscriptions offered for users wanting to store their photos and videos at their "original" quality and requiring more storage than the 15 GB offered free. Storage (GB) Per Month (USD) Annual (USD) 15 0 0 100 1.99 19.99 200 2.99 29.99 2000 9.99 99.99 You can check out how much storage you are using across Google services out of your quota of free 15 GB. Go to Google Drive and check the storage bar on the left side. Or you can click on the Setting butto...

In this tutorial, I have installed a free SSL certificate from Let's Encrypt using the Certbot tool on Google Cloud Platform VM running Debian OS that hosts a WordPress site using Apache server. You can follow similar steps for other Cloud providers / OS distributions / CMS vendors / Web servers . Part-1: Configure Virtual Host for your domain on Apache cd /var/www/html wp option update home 'https://example.com' wp option update siteurl 'https://example.com' sudo nano /etc/apache2/sites-available/example.com.conf sudo apache2ctl configtest sudo a2ensite example.com sudo systemctl reload apache2

Code: // //   main.cpp //   VaultBox // //   Created by Devharsh Trivedi on 3/11/21. // #include <iostream> #include <iomanip> #include <string> #include <map> #include <random> #include <cmath> #include <vector> int main ( int argc, const char * argv[]) {     std :: random_device ranDev;     unsigned int num_ranDev = ranDev();     std :: cout << num_ranDev << std :: endl ;     std :: mt19937 mtGen(num_ranDev);     std :: vector < unsigned long > indexes( 10 );          iota (indexes. begin (), indexes. end (), 0 );     for ( int i= 0 ; i< 10 ; i++) {         std :: cout << indexes[i] << "\t" ;     }     std :: cout << std :: endl ;

Steps to save a locked (password protected) PDF as an unlocked PDF: Download / Save / Copy the locked PDF to a folder Open Google Chrome Go to File Menu >> Open File >> Select your locked PDF Enter password Click on the Print button and select Save as a PDF The saved PDF will be unlocked This trick removes the open password from a PDF you can already open, by opening it in Google Chrome, entering the password, and then printing it back to a new PDF without protection. It only works when you know the password and are allowed to access the file, so it is for convenience, not for bypassing protection you are not entitled to remove.

Problem code: if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT , &opt, sizeof(opt)))  {  perror("setsockopt");  exit(EXIT_FAILURE);  } Solution: if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR , &opt, sizeof(opt)))  {  perror("setsockopt");  exit(EXIT_FAILURE);  } Ref.:  https://stackoverflow.com/a/59807281/4064166 This error appears when a socket option is not supported on the current platform. Here the combination of SO_REUSEADDR and SO_REUSEPORT fails because SO_REUSEPORT is unavailable, so the call returns Protocol not available. Setting SO_REUSEADDR on its own fixes it, which is widely supported and enough for the common case of rebinding a recently used address. SO_REUSEPORT behaves differently across operating systems and is not always present.