Encryption using PHP and OpenSSL

In this post we will see how to encrypt and decrypt data using PHP OpenSSL. We will be using asymmetric (public/private key) encryption. In this encryption a user generates a pair of public / private keys and gives the public key to anyone who wants to send the data. The sender of the data will encrypt the data using the public key of the receiver. The receiver will then unencrypt the received data using his own private key. The data encrypted using the public key can only be decrypted using the corresponding private key.
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How to generate passwords for .htpasswd using PHP

In my earlier post about .htaccess I had described about authentication using .htaccess and command to generate .htpasswd file. However, when we want to add passwords for many users that method will take too long, since we will have to add passwords for each user one at a time. However, there is an easier way to generate the .htpasswd file using PHP. In this post I will show the different algorithms which can be used to generate the .htpasswd file.
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How to create Triangles using CSS

Many times we come across cases where we want to have triangles, arrows or simple shapes on a site. Usually we use images to add arrows or triangles. However, this can be easily achieved by just using CSS and no need of images at all. In this post we will see how to easily we can create triangles and a few other designs using CSS.

The borders in a browser are drawn at angles, so we can use this technique to create triangle. To create a triangle we will set the border-width value for the side in which we need the arrow. Then, we will set that side’s border color and make all other sides transparent. Also, we set the width and height of the element to 0.
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WordPress add featured image to RSS feed

Recently I came across a situation when I wanted to add the featured image of the posts to my RSS Feed. By default WordPress does not shows the Featured Image in the RSS Feed. This can be easily achieved by adding a few lines of code in the functions.php file of the theme.

Here is the code that will add the featured image before the content with a margin-bottom of 10px.

//Function to add featured image in RSS feeds
function featured_image_in_rss($content)
{
	// Global $post variable
	global $post;
	// Check if the post has a featured image
	if (has_post_thumbnail($post->ID))
	{
		$content = get_the_post_thumbnail($post->ID, 'full', array('style' => 'margin-bottom:10px;')) . $content;
	}
    return $content;
}
//Add the filter for RSS feeds Excerpt
add_filter('the_excerpt_rss', 'featured_image_in_rss');
//Add the filter for RSS feed content
add_filter('the_content_feed', 'featured_image_in_rss');

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How to hide Nginx version number in headers and errors pages

In default Nginx configuration, the server sends HTTP Header with the information of Nginx version number of the Server. The HTTP response header “Server” displays the version number of the server. This information can be used by hackers to try to exploit any vulnerabilities in the Nginx, specially if you are running an older version with known vulnerabilities.

Sample HTTP Response Header:

HTTP/1.1 200 OK
Server: nginx/1.2.6 (Ubuntu)
Date: Wed, 31 Jul 2013 19:47:33 GMT

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