how to create a thumbnail image of a pdf in c#

pdf to thumbnail converter c#

itextsharp add annotation to existing pdf c#, count pages in pdf without opening c#, c# convert pdf to jpg, itextsharp add annotation to existing pdf c#, c# pdf to image conversion, pdf annotation in c#, itextsharp remove text from pdf c#, c# wpf preview pdf, itextsharp add annotation to existing pdf c#, open pdf and draw c#, extract images from pdf c#, pdf annotation in c#, itextsharp add annotation to existing pdf c#, itextsharp add annotation to existing pdf c#, open pdf and draw c#

To help you securely implement a password file, a more suitable cryptographic primitive than two-way, symmetric encryption is a one-way hash function. A hash function, h, takes a string p as input, and produces h(p). Due to the nature of how a hash function works, it is computationally infeasible to determine p from h(p). Some commonly used hash functions are SHA-1 and MD5. While SHA-1 and MD5 are commonly used, there have been recent attacks against them, and it is advisable to use hash functions such as SHA-256 and SHA-512 instead. We discuss hash functions in more depth in Section 15.1. An example of a password file that stores one-way hashed passwords is the following: john:9Mfsk4EQh+XD2lBcCAvputrIuVbWKqbxPgKla7u67oo= mary:AEd62KRDHUXW6tp+XazwhTLSUlADWXrinUPbxQEfnsI= joe:J3mhF7Mv4pnfjcnoHZ1ZrUELjSBJFOo1r6D6fx8tfwU= For each user listed in the preceding password file, a SHA-256 hash of the password is stored.2 For example, instead of directly storing John s password, automobile, in the password file, the file stores 9Mfsk4EQ... in place of it. When John s password needs to be checked, the hash of the password that is entered is computed and compared against the hash in the password file, as shown in Figure 9-1. The advantage of storing hashed passwords in the password file is that even if an attacker were to steal the password file, she would not be able to determine that John s password is automobile just by looking at the file.

Figure 9-1. Hashed password check The following code shows how to implement a mini password manager that hashes passwords. For brevity, it only shows those methods that need to be modified. public static void add(String username, String password) throws Exception { dUserMap.put(username,computeSHA(password)); } public static boolean checkPassword(String username, String password) { try { String t = (String)dUserMap.get(username); return (t == null) false : t.equals(computeSHA(password));

With all these runtime elements available to developers and a consistent server-side API (through the .NET Framework or Java server side), rich, high-performing applications built on a client/server model are now fully possible. And here is where you have to decide how you develop your client applications. One set of technologies based on HTML, DHTML, Asynchronous JavaScript and XML (Ajax), and Microsoft ASP .NET Atlas gives you the same level of sophistication that a heavy client can give you using light technologies. Features such as asynchronous updates, slick user interfaces, handy tooltips, and other embellishments, once the realm of fat clients, are now available to thin, browser-based clients thanks to advances in browser technology. The other approach, and the one at the core of this book, is an evolutionary step, where the delivery still uses the mechanisms of the thin client, including a declarative XML markup language named Extensible Application Markup Language (XAML) that defines the user interface, but has an incredibly powerful runtime supporting it. This runtime is the basis of WPF. It s a powerful rendering engine that can take the instructions passed to it from a server and render them richly. You ll see lots of examples of how to use WPF and XAML in this book. You ll use next-generation APIs for developing Windows applications version 3.0 of the .NET Framework, sometimes called WinFX or NetFX, as well as the new Windows software development kit (SDK). In the next section, you ll look at the components of this SDK and how they fit together.

2. Actually, a base64-encoded version of the SHA-256 hash of the password is stored. The SHA-256 hash of the password may contain some nonprintable characters, and the base64 encoding converts those nonprintable characters into characters that can safely be stored in a text file.

If it isn t there, the workflow would wait (using a Delay activity) for a set period of time and then look again Drag an IfElse activity after the Delay activity Leave the default name View the code of the workflow to add the branch conditions First, add a private variable to the workflow called IntCounter and define it as an integer with a value of 10: Private IntCounter As Integer = 10 Next, create the two branch conditions, one to determine if the value of IntCounter is greater than 1 and the other to determine if the value of IntCounter is less than or equal to 1: Public Sub CounterGreater1Condition(ByVal sender As Object, ByVal e As ConditionalEventArgs) eResult = IntCounter > 1 End Sub Public Sub CounterLessEqual1Condition(ByVal sender As Object, ByVal e As ConditionalEventArgs) e.

convert pdf to powerpoint online, how to protect pdf file from copying and printing online, convert pdf to jpg android online, asp net mvc generate pdf from view itextsharp