In this post I will walk you through generating RSA and DSA keys using
ssh-keygen. Public key authentication for SSH sessions are far superior to any password authentication and provide much higher security.
ssh-keygen is the basic way for generating keys for such kind of authentication. I will also explain how to maintain those keys by changing their associated comments and more importantly by changing the passphrases using this handy utility.
ssh-keygen Tutorial – Generating RSA and DSA keys
After raising the issue of the low resolution problem of the timer provided by
clock() in Resolution Problems in
clock(), I’ve ended the post by mentioning to two more functions that should provide high-resolution timers suitable for profiling code. In this post I will discuss one of them,
Continue reading Profiling Code Using
In this post I will show you how to process HTML forms easily using CGIs in C++. I assume you have already basic knowledge of writing CGIs in C++, if you don’t go a head and read Introduction to C++ CGI.
Processing forms is the basic function of any CGI script and the main purpose of CGIs. As you probably know there are two common ways to send form data back to the web server: “post” and “get”. When form data is sent with the “get” method it is appended to the URL string of the form submission URL. The “post” method is much like the “get” except the data is transmitted via http headers and not via the URL itself. When a form uses “get” it allows the user to easily bookmark the query created by the form as the data is transmitted in URL itself, on the other hand the “post” method allows to send much more data and spares to user from seeing the data in the URL.
Getting the “post” and “get” data is relatively easy. To get the data sent by “get” you can just call
getenv("QUERY_STRING") and you will receive a pointer to null-terminated string containing the “get” data. Reading the “post” data is a bit more complicated. The data needs to be read from the standard input, but the program won’t receive an EOF when it reaches the end of the data but instead it should stop reading after reading a specified amount of bytes, which is defined in the environment variable “
CONTENT_LENGTH“. So you should read
getenv("CONTENT_LENGTH") bytes from the standard input to receive the “post” data.
Continue reading Introduction to C++ CGI – Processing Forms
In this post and its follow ups I intend to cover the basics of CGI programming in C++. There are great performance gain in writing CGIs in C++ compared to interpreted languages such as PHP and it’s usually it’s even faster than PHP scripts which are interpreted via mod_php. On the other hand PHP and other traditional web development languages are well suited for the task, by means of libraries and development time. However developing small highly efficient CGI scripts in C++ is easier than you think.
Continue reading Introduction to C++ CGI