When it comes to Anti Virus software there is certainly plenty to choose from, and its pretty safe to say that most anti virus solutions offer the same thing; protection against viruses and malware. Sure, you can get all-in-one security solutions which include firewalls, web filters and spyware protectors, but the anti virus engine is the main core of the program in most cases.

I will have to admit that up until a couple years ago I had never heard of Avira, for me the only Anti Virus manufactures Id heard of were Mcafee, Kaspersky and Symantec (Norton.. eww) but I thought it was time to try something new. I have now been using Avira for over a year now and I am not planning on changing anytime soon!

Features – Avira is nice and straight forward, it offers reliable anti virus protection but also protection against the following; adware, spyware, dialers, double-extension files, phishing, security privacy risks and unusual runtime compression. This list covers most risks that you could be exposed to online and keeps you covered for the more intelligent virus developers who try and bypass anti virus software. Avira has an auto update feature to keep your virus definitions up to date. As well as this you can create your own exceptions list, more about that below. The scanning engine is fast and a full computer scan is performed quite quickly (dependent on how many files you have). Like most Anti Virus software you can set default actions for when it finds a virus and you can set it to auto delete or auto quarantine for example.

Detection Engine – The one thing that has really stood out with Avira is the detection engine, there have been several cases where Avira has detected a malicious file that other anti virus’s wouldnt have done, this means that there have been several times where I potentially could have been infected if I hadnt been using  Avira. A good way to test this is to use a site like virustotal.com, basically you upload a file to their site and it scans it with 32 different anti virus solutions, you can then see which of those detected a virus and which didnt!

When Avira think’s its found a virus or malicious piece of software you are presented with the following dialog:

When this happens you are forced to take action, all other processes are paused until you respond to this (which is a very good security feature) Your choices are straight forward, and for the most part you are going to want to delete the suspect file. The one thing about Avira is that sometimes it can get a bit trigger happy when it comes to detecting files. For example I have several tools I use such as port scanners and password revealers (for when people forget their passwords) and Avira detects them as hack tools. Luckily this is where the exception feature comes in handy and you can prevent Avira from constantly notifying you that the files are malicious.

Appearance – Avira has a very clean and simple interface and that is what I like about it. I have always hated when software companies bloat their software and make the interface too graphically intense (hmm, norton anyone?) but with Avira the interface is smooth and simple, it responds fast and everything is easy to access. Everything you could need to configure is configurable. A log file is kept of important events such as when a virus was found and what action was taken, you can also view reports for these kind of events although this is generally something you dont really need with a home solution.

As you can see the interface is straight forward and the front screen displays the most important information you need to see.

The good thing about Avira is that it will leave you alone and get on with what it has to do, it will only disturb you if its important (i.e its found a virus or it cant update) you can even set default actions as ive mentioned before which will mean you get disturbed even less!

The only bad thing about Avira is the advertisements, at least once a day you will get a popup advertising the paid solution, whilst this is a slight inconvenience I will admit that its worth it for such a robust and reliable anti virus solution. I would go as far as to say that the paid solution could well be worth the money, although im unsure as to what the differences between the free and paid versions are.

Overall Avira is great, im pretty sure its saved my skin many times where other Anti Viruses would have failed me! It runs fast, it doesnt hassle you too much and best of all its free!

The world of cryptography is vast and often very complicated, that is why today im going to go over the basics of MD5 and explain how it works.

MD stands for ‘Message Digest’ and describes a mathematical function that can take place on a variable length string. The number 5 simply depicts that MD5 was the successor to MD4. MD5 is essentially a checksum that is used to validate the authenticity of a file or a string and this is one of its most common uses. Lets take a look at a working example. Lets say you have released some software or a program that you want people to freely distribute, this is all good and well but what if someone was to tamper with your application with malicious intent? For example what if they added malware onto your program, how would people know? Well if you had taken an MD5 checksum of your original program and made this information public, then when people downloaded your software could then check their downloaded file and check that the MD5 checksum matches yours. If it does then great! If not then it means your program has been tampered with.

How does it work? – I’ll try and explain this as simply as I can, if your new to cryptography then this is where it can get complicated! Firstly the input file or string is split up into 512bit blocks, if the file or string is not divisble by 512 then it is padded so that it can be. The output for an MD5 hash is always a 128bit string. For the operation to work this is split into four 32bit words, lets call them A, B, C and D. Each of these words then performs 16 operations making 64 in total (These are called rounds). The operations work on each 512bit block, the operations are non linear functions, modular additions and left rotations. The output is then a 128bit Hex string.

Working example –

Let’s MD5 on the following string: ‘Hello World’ Here is the output:

5eb63bbbe01eeed093cb22bb8f5acdc3

Now to give you an idea on how the function works, let MD5 a very similar string: ‘Hello Worle’ Here is the output:

18c5650581f01f1a52c87eee5baa754a

Can you see how drastically difference the two strings are? In cryptography this is called ‘The Avalanche Effect’.

Vulnerabilities – MD5 is a one way function, this means it cannot be reversed. It cannot practically be bruted force either because of the length of the key. However, the most common form of attack on an MD5 string is a Rainbow Table attack. This works in a very similar way to brute force and basically uses a massive databasse of MD5 strings with their reversed outputs. There have also been numerous demonstrations showing that 2 different files can generate the same hash. Without any tampering though this is very very unlikely (the chances are 1 in several trillion trillion)

With these vulnerabilities in mind, most people are moving away from MD5 for uses in their applications, algoritihims such as SHA are more recommend when security is essential.

Nevertheless, MD5 has been around for years and still provides some decent level of security for certain things, it is commonly used to store passwords in databases (since MD5 cannot be reversed, passwords are consider secure and safe if they are stored in this format)

So there you have it, a brief and not too complicated introduction to MD5.

When it comes to surfing the net a lot of people take their anonymity very seriously and why wouldn’t they? A lot of people like their privacy and don’t like the fact that certain sites collect and store information on the user. So what can you do to prevent this and protect your privacy? Well surfing anonymously usually comes at a cost; this could be an actual cost for paying for private proxy servers or vpn’s, or a cost of speed when you notice your browsing is a lot slower when using a proxy server. First things first though, let’s take a look at proxy servers.

Proxy Server – A proxy server is basically a server that relays traffic between you and the end host and therefore masks the original sender’s identity. Let’s take an example; you want to visit google.com but don’t want to expose your ip address, so you set your proxy settings up and go to google.com. As soon as you press enter your request is forwarded to the proxy server, the proxy server then sends the request to Google, receives the content and sends it back to you.

Types of Proxy Servers – There are several different types of proxy servers depending what you need them for. The most common are:

1. HTTP Proxies – These are used in the scenario above and are used solely for web page request.
2. SOCKS Proxies – These are used for different types of traffic, not necessarily web traffic, for example they could be used for FTP, Messenger or IRC traffic.
3. Web Filter Proxies – These are used to filter web traffic for unwanted content and are usually used in corporate environments to limit users to the sites they can view.

Will a proxy server make me anonymous? – Well there are a few things to consider here. Firstly it depends on whether the proxy server you’re using is meant to be an anonymous one or not. When a proxy server requests a web page for you it may sometimes forward on a particular HTTP header that will reveal your ip address, if this is the case then no, your proxy server isn’t anonymous, because the end host can see your ip address still. If however the proxy server does not forward this header then the end host will think the request came from the proxy server and not you, therefore making you anonymous. Great! Well kind of, the other thing to consider here is whether the proxy server keeps logs or not, 99% of public ones will, and because of this you’re not totally anonymous because there is still a record of what you’ve done.

What about if I want to view blocked sites? – This is probably the most common use of proxies nowadays, people at schools, colleges etc want to view their favorite sites (facebook for example!) but cant because their web filter prevents them. In this case the most useful proxy is a web proxy. A web proxy is basically a website you visit that you then use as your browser (confused yet?) It acts in the same way as an http proxy except it doesn’t require any configuring on the clients side. For this reason these have become very popular, the problem is most of these are actually blocked by the web filters themselves, rendering them useless.

So how do you be totally anonymous online? – The things to look out for here are whether your ip address is revealed and whether the proxy server keeps logs. Well a lot of proxy servers won’t forward your ip address, but finding a public one that doesn’t keep logs is unlikely. For the casual browser though this shouldn’t be a big concern, for those after true anonymity though, they should consider a paid option, whether it be private proxy servers or a private VPN.