Calculate SHA-256 programmatically

SHA-256 is 256 bit hash value calculated by SHA-2 (Secure Hash Algorithm 2). SHA-256 is used in some of the multiple well known authentication and encryption protocols, including SSL, TLS, IPsec, SSH, and PGP. Also it is used for secure password hashing and cryptocurrency transaction verification. Here is c++ example how to calculate SHA-256 has… Read More »

How to get openssl cipher list programmatically

The cipher list may be retrieved using “openssl cipher” command. This command has multiple options to filter output. The same is possible to do programmatically using openssl API. Here is c++ example how to programmatically obtain a list of available ciphers with appropriate cryptographic protocols they belong to. The code was implemented and tested on… Read More »

Simple method of bash script step debugging

I always wanted to be able to debug bash scripts just like any other code and I did not know how to do in for very long time. However it is easy to do using trap command which may intercept different kind of signals and exceptions. Adding trap in some place of your script you… Read More »

Openssl BIO API, file saving and reading examples

The acronym BIO stands for Basic Input/Output. It is multipurpose API for various types of input and output operations, including file, memory buffer, networking. The main header file for BIO methods is bio.h, binary linking references are presented in libcrypto.so library. Below presented 3 examples of BIO API file usage which create and read 3… Read More »

How detach forked process from parent process

A child forked process in Linux inherits most of parent process attributes, such as file descriptors. Basically a child process basically represents a copy of the parent. setsid() function may help to break this inherency. “man 2 setsid” gives us the following information about this function: setsid() creates a new session if the calling process… Read More »

HTTP 418 response code.

The HTTP 418 code description is “I’m a teapot”. in other words this response code means that the HTTP server refuses to brew coffee because it is, permanently, a teapot. This code is defined in RFC 2324 and RFC 7168 (section 418 I’m a teapot). This code was defined as April Fools’ joke and usually… Read More »

Removing trovi.com from Chromebook

I bought new Chromebook at Costco and found that my Chrome browser redirects me to trovi.com search engine. I did not know anything about trovi and after googling I found that trovi is classified as browser hijacker which modifies a web browser’s settings without my permission. Definitely it does not look good. Before removing trovi… Read More »

Assembler and Inline Assembler Code in g++

My career as software developer began with embedded programming for 8-bit microprocessor. The main language I used in that time was assembler. Processors changed as assembler changed as well. Later when I started develop Windows implementation in C++ I also used inline assembler instructions in my C++ code, sometime it was necessary for example when… Read More »

Installing Torrent Client on CentOS VM

Torrenting on virtual space on your device is more secure that host machine environment. Isolated VM environment protects somehow from malicious software. However it is 100% secure. I began with webtor.io which is online torrent which does not require any installation but it displayed a lot of annoying pop-ups with links to suspicious software. So… Read More »

Create Frontend Development Environment Fast

I wrote this post for myself as quick reminder how to create web frontend ADE from scratch. Two components must be install VSCode and Node.js with npm (Node Package Manager). Both components may be installed on different operating systems: Windows, Mac or Linux. I was using Mac OSX. VSCode may be downloaded from