1. Note for captcha decoding fighter: If you want to have a good CAPTCHA, use any method witch a decoder can't recognize the characters, even with a Neural network. Deform the characters randomly, use many fonts instead of one and rotate the characters as well, etc. Finally, we concatenate all single characters into one and return it as result.
2. Since that is a social device the cracking is also social. They piped the images of CAPTCHA to a harmless striptease site and trick others to read it for them.
3. Contribute to nanfengpo/crack_captcha development by creating an account on GitHub.

1. Captcha How To Disable
2. How To Break Captcha Php
3. How To Crack Captcha Php Examples
4. Simple Captcha Php
5. How To Skip Captcha

Captcha How To Disable

How To Break Captcha Php

I have seen some captchas being decode using javascript, php, etc. How do they do it?

After you fill the web form, additionally you have a challenge to enter the correct captcha code. If all OK you can submit the form. At the server side first task is match the generated captcha code with the entered captcha code. Before process the request, you need to pass the captcha verification test. Once you have entered the captcha code correctly, computer recognize you as a real human and execute the rest of the program. Search for jobs related to Crack captcha php script or hire on the world's largest freelancing marketplace with 14m+ jobs. It's free to sign up and bid on jobs.

For example, very popular megaupload site's captcha has also been decoded.

How To Crack Captcha Php Examples

5 Answers

See:

Here John Resig (creator of JQuery javascript library) explains how exactly it is been done.

SarfrazSarfraz

I'm an image processing specialist and CAPTCHA decoder, I've done many CAPTCHA resolving projects before.

OK, let's start CAPTCHA resolving steps!

Decoding any kind off CAPTCHA has 3 main steps:

1- Removing background

Clear the CAPTCHA from any noise (using any image processing methods).

Note for captcha decoding fighter: If you want to have a good CAPTCHA, you should add a stronger noise. Use random noised background that has similar color of characters.

2- Splitting characters

Easy step when they are separate and very hard when they're not.

*Note for captcha decoding fighter: If you want to have a good CAPTCHA, don't leave the character separate! Make them overlapping, do NOT use different colors for characters, decoders can split the characters very easily! (most of the developers are unaware of this and think it's better to use a colorful CAPTCHA!), the best one is making an overlapping string with black color. For an experienced CAPTCHA decoder, it's not a problem to decode a colorful CAPTCHA! It's just beautiful and not useful! :) Use random curved lines witch connect all characters to each other. *

3- Converting separate images into character

After separation, we have a character set, (we don't have any string now, just have images and pixels), we should convert character images into string, But how?!There are several ways, if they are not rotated, and have fixed font and size (such as freeglobes CAPTCHA), you can define a pattern set, your program should loop throw the patters to find the best match for each image, if the characters is very different and needs a large pattern you should use a 'Neural Network' to recognize the character. A neural network for CAPTCHA resolving, will takes a character, and we say the network what this character is, for example, we will give it an image of 'A' and we tel the NN: it's 'A'! , then it will 'LEARN' this character and will save its learning into a database, This procedure called 'TRAINING'. So, when we ask a trained network for a new character again, it will return us the best match from it's learning database. Usually decoder specialists use the CAPTCHA itself to train the neural network. Be careful! Using appropriate data for training can make or break your results.

Note for captcha decoding fighter: If you want to have a good CAPTCHA, use any method witch a decoder can't recognize the characters, even with a Neural network. Deform the characters randomly, use many fonts instead of one and rotate the characters as well, etc.

Finally, we concatenate all single characters into one and return it as result.

Unfortunately, there are no fixed algorithm for solving any CAPTCHA, it means, new CAPTCHA needs new analysis and training. You can't make a CAPTCHA decoder to decode all CAPTCHA. Driver printer canon f 15 1300.

What should you know before starting:

1- Image processing fundamentals

2- General understanding of a Neural Network

3- Simple image processing functions (in any language)

For PHP:

For .NET:

For JavaScript and HTML5:

Simple Captcha Php

Lastly:Note for captcha decoding fighter: If you are wonder about how someone can decode a CAPTCHA and want to prevent it from decoding, you should first be a CAPTCHA decoder yourself or hire someone knows the weakness and attacking algorithm very well!

Hope to help! ;) https://fancyavenueprince.tumblr.com/post/632570212596727808/dungeon-keeper-3-mac-download.

Take a look at PWNtcha

You can also read Breaking a Visual CAPTCHA

Boris GuéryBoris Guéry

I was involved in a project to circumvent Captcha images on the TicketMaster website about 8-9 years ago for a third-party ticket seller. When an event went on-sale, like a concert, our network of machines would use multiple credit cards and mailing addresses to buy any and every seat possible in the first 10 rows.

Rather than generating new captcha's each time, TM had a limited pool of images they could re-use. We'd create a unique digital fingerprint (checksum) for each image, then simply attack it with some imaging tools (LEADTOOLS.com) (to remove extraneous elements, enhance contrast, etc) and then use OCR tools. It was surprisingly effective.

We were able to crack a great number programmatically, and we'd store the ones we couldn't crack for human processing. Sometimes they'd have a pool of 20K images, so at first we'd get maybe 60-70% automatically, but eventually we'd get 100% success because we could identify the images our humans processed (offline) based on looking up their hash in our database. (That is, we could check a captcha image against our database based on the hash we created and if we already had the solution we could just submit the answer immediately.)

How To Skip Captcha

/canon-ir2270-ir2870-pcl5e-scanner-driver-free-download.html. Occasionally, they'd flush and replace their pool of captcha image images with a new set, but again, it would just take us a bit of time to get back up to a 100% rate. The fatal flaw with this particular system was that they recycled images, rather than programmatically generating new captcha images each time.

But the fact is, if the financial incentive to crack the capthcha is high enough, it doesn't take much to create a distributed platform where low-wage unskilled workers can sit around earning pocket change to crack them all day.

Inside India's CAPTCHA solving economyhttp://www.zdnet.com/blog/security/inside-indias-captcha-solving-economy/1835

Max HodgesMax Hodges

There are services for recognition. Such as 2captcha. This is a tool for solving php https://github.com/jumper423/decaptcha/

The challenge in breaking a CAPTCHA isn't figuring out what a message says -- after all, humans should have at least an 80 percent success rate. The really hard task is teaching a computer how to process information in a way similar to how humans think. In many cases, people who break CAPTCHAs concentrate not on making computers smarter, but reducing the complexity of the problem posed by the CAPTCHA.

Let's assume you've protected an online form using a CAPTCHA that displays English words. The application warps the font slightly, stretching and bending the letters in unpredictable ways. In addition, the CAPTCHA includes a randomly generated background behind the word.

A programmer wishing to break this CAPTCHA could approach the problem in phases. He or she would need to write an algorithm -- a set of instructions that directs a machine to follow a certain series of steps. In this scenario, one step might be to convert the image in grayscale. That means the application removes all the color from the image, taking away one of the levels of obfuscation the CAPTCHA employs.

Next, the algorithm might tell the computer to detect patterns in the black and white image. The program compares each pattern to a normal letter, looking for matches. If the program can only match a few of the letters, it might cross reference those letters with a database of English words. Then it would plug in likely candidates into the submit field. This approach can be surprisingly effective. It might not work 100 percent of the time, but it can work often enough to be worthwhile to spammers.

What about more complex CAPTCHAs? The Gimpy CAPTCHA displays 10 English words with warped fonts across an irregular background. The CAPTCHA arranges the words in pairs and the words of each pair overlap one another. Users have to type in three correct words in order to move forward. How reliable is this approach?

As it turns out, with the right CAPTCHA-cracking algorithm, it's not terribly reliable. Greg Mori and Jitendra Malik published a paper detailing their approach to cracking the Gimpy version of CAPTCHA. One thing that helped them was that the Gimpy approach uses actual words rather than random strings of letters and numbers. With this in mind, Mori and Malik designed an algorithm that tried to identify words by examining the beginning and end of the string of letters. They also used the Gimpy's 500-word dictionary.

Mori and Malik ran a series of tests using their algorithm. They found that their algorithm could correctly identify the words in a Gimpy CAPTCHA 33 percent of the time [source: Mori and Malik]. While that's far from perfect, it's also significant. Spammers can afford to have only one-third of their attempts succeed if they set bots to break CAPTCHAs several hundred times every minute.

You'd think that the inventors of CAPTCHA would be upset that their hard work is being picked apart by hackers, but you'd be wrong. Find out why in the next section.