Practical Hashing
This is my first blog here and this will be about cryptographic hash functions. I have chosen this as the topic for my first post as hashing functions are very common in the field of cryptography, which is an area of interest of mine.
A hash function takes a string of bits or bytes as an input and returns a fixed-size string of bits or bytes as the result. The result is known as hash, fingerprint, message digest, etc. A good hash function must satisfy the following criteria:
- It should be easy to calculate the hash for a given input.
- Given a hash, it should be extremely difficult to find the input.
- Given a hash for an input, it should be difficult to find another input which has the same hash.
- It should be difficult to find two inputs which have the same hash.
We will not discuss more about its properties and attack-complexities. We can do that in some other post. Now we will see how to use hash functioons in a few programming languages. Three examples are given in C, Python and Java. While working with cryptography, one first needs to decide which library he is going to use. For this blog, I will choose the OpenSSL crypto library for C, the Python Cryptography Toolkit and Java Cryptography Extension.
OpenSSL Crypto Library
Installing it on Debian is easy since it is available as the package called libssl-dev. I installed it on my Debian system by running the command: aptitude update; aptitude install libssl-dev. For other systems, you’ll have to figure it yourself. If you want to build it from source, go to: http://www.openssl.org/source/.
DDoS Attacks and DDoS Defense Mechanisms
Introduction
Distributed denial-of-service attacks (DDoS) pose an immense threat to the Internet, and consequently many defense mechanisms have been proposed to combat them. Attackers constantly modify their tools to bypass these security systems, and researchers in turn modify their approaches to handle new attacks.The DDoS field is evolving quickly, and it is becoming increasingly hard to grasp a global view of the problem.
DDoS Attack Overview
A denial-of-service attack is characterized by an explicit attempt by attackers to prevent legitimate users of a service from using that service. A distributed denial-of-service attack deploys multiple machines to attain this goal. The service is denied by send...
Unable To See Hidden Files
We must have usually faced a problem that we cannot ‘view the hidden files’, even after selecting the option from the Folder Options Menu, and when we go back to check, we see that it has been mysteriously restored to ‘Do Not Show Hidden Files & Folders’.
It happens due to a small bug/virus which edits the Registry to create trouble for us.
Here is how we can solve it :
- ☻ [Theoretical Way]
Go to Registry Edit
[Start -> Run -> type "regedit"]
Browse to :
“HKEY_LOCAL_MACHINE\SOFTWARE\ Microsoft\Windows\CurrentVersion\ Explorer\Advanced\Folder
\Hidden\SHOWALL”
and set the value of the key “Checked Value” as 1
- ☻ [Practical Way]...
Practical Compiler Development Part 1
Practical Compiler Development Tutorial – Part 1
This is a rather informal introduction to development of a hobby compiler . The more formal chapters on compiler development will be given in later tutorials. By the end of this tutorial you will be able to create a simple interpreter . This can be easily converted into a compiler. The requirements for following this tutorial are
1. A reasonable grasp of C / C++ / Python / C# / Java
2. An elementary knowledge of basic data structures and recursion
Compiler defined
A compiler is defined as a program that converts a source file in a...
Dynamic DLL Injection
As in my previous post I describe about the static dll injection Now we will look at the dynamic dll injection. which is mostly used by Trojan’s.
After a program has been executed, a process is created in the OS. When an attacker attempts to load code into the process memory space, then the attacker is using dynamic injection. When .dll libraries are loaded through dynamic injection, the process is known as dynamic dll injection.
Loading a .dll into a process.
For this we will install DiamondCS APM (Advanced Process Manipulation).or any other advanced process manipulator just Google it
After installation start APM.
you should see a list of running processes along with their Process ID n...
Get rid of Windows Vista Administrative Password
Method 1: System Restore
This only works in cases where you changed your password to something new and then forgot it or deleted a user account by accident. In order for this to work, there must be a System Restore point at which a logon was successful for the problem account. Also, this is not a problem if you are in a domain environment because the Domain Administrator can always reset your password.
1. The first thing you’ll need to do is make sure you have your Windows Vista DVD or a repair disc. Insert the disc and then restart the computer. When asked to “Press any key to boot from CD or DVD”, go ahead and press any key.
2. Click Next until you get to the screen that has the option “Repair you...
Quantum Computing the new Horizon in Computing History
The massive amount of processing power generated by computer manufacturers has not yet been able to quench our thirst for speed and computing capacity. In 1947, American computer engineer Howard Aiken said that just six electronic digital computers would satisfy the computing needs of the United States. Others have made similar errant predictions about the amount of computing power that would support our growing technological needs. Of course, Aiken didn’t count on the large amounts of data generated by scientific research, the proliferation of personal computers or the emergence of the Internet, which have only fueled our need for more, more and more computing power.
Will we ever have the amount of computing power we need or want? If, as Moore&...
Static DLL Injection
INTRODUCTION
DEFINING DLL
According to microsoft “A DLL is a library that contains code and data that can be used by more than one program at the same time. For example, in Windows operating systems, the Comdlg32 DLL performs common dialog box related functions. Therefore, each program can use the functionality that is contained in this DLL to implement an Open dialog box. This helps promote code reuse and efficient memory usage.
By using a DLL, a program can be modularized into separate components. For example, an accounting program may be sold by module. Each module can be loaded into the main program at run time if that module is installed. Becaus...
Semantic E-mail Delivery: The Future of E-mail?
Smart email figures out who should get messages.
… new cutting edge technology? or just another waste of time? Perhaps you might discover a life-changing potential so stay tuned.
A prototype e-mail system being tested at Stanford University later this year will radically change how users specify where their messages are supposed to be delivered. Called SEAmail, for “semantic e-mail addressing,” the system allows users to direct a message to people who fulfill certain criteria without necessarily knowing recipients’ e-mail addresses, or even their names.
(more…)
