Create private backup of your web site

Everything may happen, but being wise after the event sometime is not a good choice. On Saturday 28 August 2021 incident happened the data on servers of my Webhosting provider were wiped, some backups were destroyed also on many server machines. You can read more about this here . Most likely it was a Ransom… Read More »

Remote desktop from Mac to Windows and input control matching.

Recently working from home I needed to use remote desktop connection from Mac to Windows computer. Microsoft remote desktop client is available on the App Store. There was no problem with Microsoft Remote Desktop installation on Mac laptop and connection to Windows PC. The main difficulties appeared with using Mac keyboard with Windows applications. Later… Read More »

The GPG_TTY environment variable or github commit problem

I used a lot of different source control systems: SVN, CVS, Rational ClearCase, Perforce Helix, Bitbucket and others. Currently I am on github. Github looks indeed complex, even after Bitbucket which is based on git solution as well. Recently I cloned my repository on new Azure Linux virtual machine, everything was OK until commit step.… Read More »

Get Thumbprints from Windows Catalog File on Linux

This article is related to the “Windows Catalog Files” post and describes how to parse catalog sis.cat file using posix c++ on Linux platform. On Windows as it is mentioned in “Windows Catalog Files” it is possible to retrieve thumbprints with mscat.h API. The Linux parsing method is based on searching positions of some OIDs… Read More »

Simple WebSocket Test on the Server Side

WebSocket protocol is a suitable way to create a reliable two directional connection between a server and a client. WebSocket is using the same ports as HTTP/HTTPS protocols: 80 and 443. However very frequently WebSocket is not such transparent as HTTP and may be blocked by firewalls, proxy or antivirus applications. Anyway if multiple WebSocket… Read More »

Windows Catalog Files

Windows Catalog file is used to store hash checksums or thumbprints of any collection of files to validate its authenticity. Besides the Catalog file may be digitally signed and be used as group digital signature of the files which thumbprints are presented in this Catalog file. Catalog file may be generated from text catalog definition… Read More »

Alice, Bob and Asymmetric Cryptography

I suppose a lot of people know about Alice and Bob, the characters of many cryptographic tales. Previously I posted article “Encrypt and Decrypt Data on Linux Devices using OpenSSL” which explains how encrypt and decrypt files in symmetric way, currently I want to do the same using asymmetric cryptography, exactly how Alice and Bob… Read More »

Experimenting with ECB and CBC Ciphers of AES

The openssl help shows 2 groups ciphers with ECB (Electronic Code book) and CBC (Cipher Block Chaining) suffixes. For example aes-128-ecb and aes-128-cbc or aes-256-ecb and aes-256-cbc for AES (Advanced Encryption Standard) ciphers. In ECB mode input data is divided in blocks of the same length. Then every block will be encrypted with the same… Read More »

Changing Certificate Verification Flags in openssl

Recently I was needed to modify some flags for verification of X.509 public key certificates. These flags defined in x509_vfy.h include files. Particularly it was necessary to set X509_V_FLAG_X509_STRICT flag, which enables additional security checks and turns off workarounds for broken certificate chain. In other words this flag makes the certificate verification more strictly. This… Read More »

Big Sur and built-in dynamic linker cache

On Big Sur Apple made significant changes in OS X file system. System-provided libraries are moved from filesystem to dynamic linker cache. Probably it is done because Big Sur OS X supports 2 different CPUs: Inter and Apple Silicon processors and currently dynamic linker cache contains 2 versions for the both processors: Apple Silicon ARM… Read More »