There are many reasons a PDF might be locked. The author may want to prevent unauthorized editing, or in the case of a magazine, the publisher may want to prevent readers from printing the online version. I honestly rarely have a need for this kind of thing, but it does come up, so when Eltima Software asked if I wanted to review a copy of their software, Recover PDF Password, I agreed. They also offered up a couple more free licenses to my readers, so read to the end to find out how to get a free license or cash.
How it works
Like many password crackers, Recover PDF Password uses a “brute force” method to guess at a password. By this, I mean that it tries every combination over and over again until one matches. One thing I liked was that I could choose to exclude some of the more complete searching options like special characters ($%^&*, etc), numbers, or upper case letters to name a few. This speeds up the search incredibly at the risk of missing the correct password completely if it has one of these characters. To give you an idea of the speed difference, imagine you’re lucky enough to know that the password is six characters in length. To just try searching with the lower case alphabet, (if my math is right) the software has to try up to 308,915,776 possible character combinations (26 * 26 * 26 * 26 * 26 * 26). If you add in 26 upper case alpha + 10 numeric + 28 special characters, you get 90 characters total and 90 * 90 * 90 * 90 * 90 * 90 makes 5.31441e+11 (531,441,000,000) possible combinations to try. That’s about 1,720 times more than just lowercase alpha characters. Having the option to pick and choose is a big plus. Remember, too, that this is if you’re lucky enough to know the password length and it’s only six characters. The problem with cracking passwords is a matter of the time it takes, and this program does in hours what it would take you a lifetime to do on your own.
What I think is missing is the ability for the software to try dictionary words first. A good password will be a combination of upper and lower case alpha characters, special characters, and numeric digits, but let’s face it… too often, the password is merely “password” and a large portion of the rest are dictionary words. Using the method above, it might take 19 billion or so tries, give or take a billion, to conclude that the password is “password”. Trying all the 8-character words from a dictionary file would take somewhere in the tens of thousands of guesses. This is a feature I’d really like to see in any password cracking tool, as it should be used as a first pass, just in case.
My tests
First, I downloaded Recover PDF Password. The download took about a half hour, but I tried again (twice) later, and it came down in around 14 seconds both times. Then, I grabbed a random (locked) PDF from the web. I first tried with all the options on and was getting nowhere after a day. I decided to start over, telling it to try anything with lowercase characters and numbers from three to four characters in length. That went pretty quickly, eliminating all possibilities. Next, I moved on to 5-6 characters, which took a lot longer, as expected, due to the exponential growth in combinations to try. The program eliminated all 5-character combinations and then, about a third of the way through the alphabet, it recovered a 6-character password for me. The total search took 19 hours, 50 minutes, 28 seconds, and used about 50% cpu and 25MB of RAM pretty consistently.
After thinking about my wish that a dictionary file be used for the first pass, I decided to try a PDF with a password of “password” just for kicks. I grabbed one from Adobe’s site and set Recover PDF Password loose on it, trying only lowercase alpha characters and only with a length of 8. After about five minutes, it was estimating 100-108 days remaining.
Conclusions
First of all, it does what it says, so that’s good. At the $39.95 price for a personal license, it’s also within reach of anyone needing to recover a password on a PDF without breaking the bank. The down side is that a good password will take a very long time to crack, but that’s going to be true for any program, I guess. I’d love to see a dictionary file used, but it won’t make a difference for a secure password. The software is solid and complete with useful options to help save time and it’s worth the purchase as long as you can let it run in the background for a while.
UPDATE: Eltima Software tells me that they are now working on implementing the request for use of a dictionary file. That’s great news.
Get a free license
Want to try it out yourself or just have it handy for when you really need it? Eltima Software gave me two licenses to give away to readers. All you have to do to try for one is tweet with “http://Lnk.gd/ej” and “@joetech” and you’ve earned an entry. If someone re-tweets your tweet, you get another entry for every RT. Just to spice things up a little, I’ll throw in $20 (via PayPal) to a third winner. I’ll draw three twitter users at random from those who have entered. To collect, I have to be able to send you a direct message, so make sure to follow @joetech in case you win.
They’re here, they’re there, they’re everywhere. We’re inundated with gadgets no matter where we go or which way we turn. While some are indispensible, there are others that we want to own for reasons other than utility value – status, good looks, or for just pure entertainment purposes. Gadgets that are innovative and quirky tend to catch our attention, even though they may not be good value for money or something that we would go searching for when we shop. But, it’s stuff like this that perks up the monotony of life and makes for interesting conversation. So while some people may find the following gadgets useless, I’ve reason to believe they do justify their cost:
• Flying Alarm Clock: If you have trouble getting out of bed every morning, even on those days when it’s imperative that you absolutely must be up at 5 am, then this is just the thing for you. It uses sheer irritation to get you out of bed – you actually do so only to break the damn thing because of the loud screeching noise it makes; to turn off the racket, you must find the propeller-like wheel that shoots off the clock when the alarm goes off and buzzes across the room to settle in some unknown corner. The saving grace – by the time you’re done finding the small thingy, you’re probably too angry to go back to bed. The clock saves the day!
• Message Toaster: Now you can literally make someone “eat their words”. This toaster burns what you write on a message pad on the top into the slice of bread that pops out for your breakfast. While some might use it to propose more than a toast, those who are more practical (albeit in a whimsical way) use it to leave notes or messages for their significant other. But my personal favorite usage for this is to remind someone of what they said, something that has since then been proved untrue – yes, you’re making them eat their words!
• USB Fragrance Burner: If you work in a closed environment where all the windows are shut (or are non-existent) and the air conditioning system is on 24/7, you’ve probably been through situations where you have to stop breathing if you want to avoid throwing up. Working in close proximity to other people in closed environments can have that effect what with natural gases and other smells permeating the atmosphere from time to time. The USB fragrance burner is just what you need for mini emergencies like these – available in aromas of rose, jasmine, peppermint and lavender, you can just plug this gizmo into your USB port, add a few drops of the perfume that accompanies it, and you’re good to go. Makes for a work environment with clean air and unwrinkled noses!
This guest article was written by Adrienne Carlson, who regularly writes on the topic of accredited online degrees. Adrienne welcomes your comments and questions at her email address: adrienne.carlson1@gmail.com.
I’ve reviewed other lasers, but recently, I got another green laser pointer in the mail. This one came from SKYlasers High Power Laser Pointers and it’s not like the others because it comes with a unique feature I haven’t seen on the other laser pointers that have come my way.
The extra mile
What makes this laser stand out from the others I’ve been sent is the lock and key. If you look at the bottom photos below, you’ll see on the left is the end of the laser pointer that the key fits into and on the right is the key in use. You’ll notice that there’s three positions: low, high, and off. The ability to turn the laser off when not is use is a big plus for me, because I definitely don’t want to have a laser like this on accidentally and not notice until it becomes a problem. More importantly, I can imagine what a selling point this might be for laser-happy parents. Kids will be kids, and it helps if you can just prevent them from being able to use the laser by just locking it.
The balloon test
So how well does this laser work? To begin with, I just had to put it through the balloon test. For those unfamiliar, a powerful enough laser pointer can pop a black balloon. It’s a fun way to test it, so I headed to the store and picked up a bag of black balloons. The first attempt at my office worked extremely well. The balloons were very still and I popped them from about three feet away. Unfortunately, that video got deleted, so I did it again from my house. This time, I did a big one and a smaller one, the fan was on, and I started from about six feet away. The results started without a bang, so to speak, but when I moved in to about three feet, both balloons popped without a lot of wait. That video is below.
Some laser art
In addition to the standard balloon test, I wanted to do something different for this review. In previous reviews, I lit up water, tested the distance by pointing it out into the night sky, and split the beam with diffraction gratings. With my new SKYlaser green laser pointer, I decided to try out some laser art.
To get this effect, I just set my camera on a tripod in fully manual mode and set the exposure to 30 seconds. Then I snapped a shot and “drew” with the laser by waving it around for those 30 seconds while the shutter was open. The result is what you see above and the rest of the photos I took.
While you should always be careful with the more powerful laser pointers like this one, they can be a lot of fun and can also be highly useful. Some colleagues are using lasers to map their robot’s surroundings on a virtual laser grid. Others have built laser harps, and the list goes on.
Conclusions
The laser pointer I was sent is truly too much for what I did (and will do) with it. At about $300, it’s not the one I would normally buy, especially since I don’t have any of my own advanced projects that require a 150 mW. If you do, this is a great laser. For the rest of us, this is not the only laser they sell. Skylasers offers a good variety of lasers from much less powerful laser pointers that start in the $40 range to some serious hardware upwards of $600. This laser seemed like it was good quality and it came on every time I tried it. Comparatively, it’s about $80 less than one competitor I previously reviewed and the same price as another. I’d rather have it black in exterior color, but for the price, I’d have to say the locking feature makes this one my favorite so far.
I spend a lot of time online. I think it’s somewhere around 16-18 hours a day, really. Because of this, I also spend a lot of time looking things up, from directions to music lyrics to how to fix a computer. Today, I thought I’d share some of my favorite resources. While this list certainly isn’t complete, I think it represents some of the most useful sites on the Internet when it comes to finding things online.
Information Google – As a developer, I’m constantly looking up functions, code examples, error messages, etc. and Google is the number one source for finding what I need quickly, be it code examples, recipes, what time it is in London, etc. Tips: Try the advanced search and then watch what it puts in the search box when you submit. You’ll learn a lot of useful tips to refine your searches. Also, note the links at the bottom of the advanced search. When looking for a song you heard but only know some words to, type in a lyric phrase (in quotes) that includes a unique word for more precise results.
Bing – I’m a fan of Google and Microsoft is the company everybody loves to hate, but MS seems to have come out of the gate with a pretty solid offering this time around. There’s things I’d change about it, but Bing is definitely worth a look. Tips: ToThePC.com has written 10 Bing Search tips & features for better searching.
Wolfram Alpha – WA was hyped for months because of it’s intelligent search features. Instead of a flexible, yet broad, search, they offer specific information presented in a report-like fashion. If you’re looking for a grouping of information about a person or company, this is a good place to start. It’s a bit like a mix of Google and Wikipedia Tips: Try searching for a gadget by name or just type in a mathematical equation. Try entering a few stock symbols and see the comparisons.
Yahoo Answers – Yahoo has lost a lot of ground in search, but they’ve come out on top when it comes to the answers game. Yahoo Answers is a great source for personalized answers when you can’t find what you need at the above sites. Ask a question and people answer and even help you choose the best answer. Great system. Tips: Be patient. You’ll need to wait for human interaction, unlike a Google search. See if your question already has an answer. Answer questions from others. It helps your karma and earns site points, too.
Music GEMM – Over the years, I’ve had a few drinks bought for me because I found some obscure album hiding away in a small shop in the Netherlands for a friend. Every time, it was a result of searching GEMM. If it’s rare and you need it badly, this is the place to look. Tips: If cost isn’t a factor but getting it now is, just search and buy, but you can also wait for another seller to have your item cheaper. Either way, be aware of seller feedback. I’ve never had a problem, but the feedback might be why.
CD Universe – CDU was the second site I ever found selling a wide variety of music online. Now offering movies and games, too, they are a great resource when you want the physical item and not just a digital download. Tips: Watch for weekly deals and releases. Also watch for pre-orders so you can be assured to get that newest album as soon as it drops.
Software Download.com – Usually, if I need commercial software, I run to Best Buy for it, but most times, I just need a video converter, chat program, or some other utility that can be found often for free or a low price at Download.com Tips: Filter by your operating system from the start to save time. Sort by user rating and if you have to have free only, filter by license before you download something just to find it’ll cost $100 after 10 days.
Images Google Image Search – I use Google to help me find images several times a week. It’s fast and (mostly) reliable for finding what I need. Tips: Use advanced searching like web search. Filter by size to find wallpapers or icons.
Flickr – Flickr is a great way to quickly find more photos from the concert you went to or even royalty free images for your blog posts. Just last week, I searched for “Woodstock 94″ and found lots of great photos that other people took. It was like I was there again. Tips: Search groups or images and use the sorting options. You can refine your search by showing images where your search words match the tags only.
Directions Google Maps – Always my favorite for any geographic search, Google Maps shows me as little or as much detail as I want. I can even use street view to see what a place looks like so I’ll recognize it when visiting for the first time. Tips: Zoom in to the area you want to find a business in and then search to see all results in just that area. As mentioned above, use street view to see what you’re friend’s house looks like before dropping by for the first time. Wander around in street view some time. There’s some interesting things to see.
BONUS: Products eBay – I was all set with my list of 10 sites, when I realize I couldn’t dare leave out my favorite product resource. eBay is my first stop when I want to find a product. Many times, I want something very specific and eBay seems to have the largest selection at varrying prices. If I’m looking to buy something, I can usually find it on eBay. Tips: If there’s a lot of an item but also a lot of buyers driving the price up, look for it outside of the expected category or look for a misspelling in the title. You can often find something with little to no bidding competition this way and get in cheap.
I’m sure some of you, at this point, are thinking “What about… ?” If you have a good site in mind that you think should have made this list, please add it in the comments and don’t be shy about including tips. What sites do you used to find things online?
