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Stiltwalker Redux Adam, C-P, Jeffball DC949
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CAPTCHA Completely Automated Public Turing test to tell Computers and Humans Apart
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Why reCaptcha? Shmoocon Twitter Contest C-P
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Round 1 Wordlist: 58 Words Colors, Numbers, Vehicles, Days of week, Kitchen Things Captcha 6 words 8 seconds Play me
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Splitting Words Apart Round 1
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Neural Network Machine Learning (Supervised)
Similar To Linear Regression Linear Algebra Matrix Operations Not Enough Time To Explain It All
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How Neural Networks Work
Feature Selection 2048 inputs 1536 hidden nodes 58 outputs 0-2.69 red blue Hz
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How Neural Networks Work
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How Neural Networks Work
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How Neural Networks Work
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How Neural Networks Work
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How Neural Networks Work
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How Neural Networks Work
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How Neural Networks Work
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How Neural Networks Work
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How Neural Networks Work
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How Neural Networks Work
Feature Selection 2048 inputs 1536 hidden nodes 58 outputs 0-2.69 red blue Hz
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Initial Accuracy: 99.1% Test run 17338 / 17495 846 in a row
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Rate Liming By Accuracy ~60% Turing Test? We RZ human
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Hmm, This Sounds Familiar...
Finite number of challenges The ENTIRE CAPTCHA is repeated Pre-generated or done on-the-fly? ~15 million already solved (61% accuracy)
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Round 2 Wordlist: 10 possible Digits Captcha 12 digits 12 seconds
3 groups of 4 digits Play me
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Splitting
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Fuckit Splitting
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Neural Network Solver Nothing new here, still works
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Round 2: 63.18% Test Run 6318 / 10000 More samples = better accuracy
Live for 28 hours
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Hmm, This Sounds Familiar...
They wouldn't do that again...
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Round 3 Wordlist: 59 possible words Captcha 6 or 10 words
16/30 seconds Numbers, colors, days, months, animals, misc Play me
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Splitting
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Low Frequencies
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Neural Network Solver SSDD
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Round 3: 59.5% Test Run 911 / 1531 More samples = better accuracy
Live for 2.5 days
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Hmm, This Sounds Familiar...
They wouldn't do that again...
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Round 4 (Current) Wordlist: ?? possible words Captcha 6-12 words
16-36 seconds Impossible to do by manually 0/30 Play me
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Splitting
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SoX Noise Reduce
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Unfinished 0/30 manually No sample data for Neural Network
Unfathomably impossible for humans
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But wait, there's more: Nucaptcha
Wordlist: 36 words (Digits and Letters) Captcha 3-4 words Repeated twice (8 seconds total) Play me
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Splitter
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Neural Network Solver SSDC
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Nucaptcha: ~93.80% Test Run 106 / 113 Kind of annoying to test
(Not because of behavior analysis) Behavior Analysis Fields Nucaptcha-answer-enter Nucaptcha-answer-exit Nucaptcha-media-download-time Nucaptcha-adserv-download-time
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Hmm, This Sounds Familiar...
Really small amount of captchas (< 1000) Only repeats on per site basis
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But wait, there's more: Paypal
Wordlist: 31 words (Digits and Letters) Captcha 5 words Fuckit Splitter NN Solver SSDC Play me
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Paypal: % Test Run 2291 / 2412
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But wait, there's more: Securimage
Wordlist: 36 words (Digits and Letters) Captcha 6 words (Many variants) Fuckit Splitter NN Solver SSDC Play me
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SecureImage: 60.89% Test Run 766 / 1258 More Samples = Better Accuracy
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But wait, there's more: Slashdot
Wordlist: Huge List Captcha “Word W – O – R – D” Chrome Solver Play me
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Slashdot: 56.08% Test Run 530 / 945
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And the worst audio captcha: Davids Summer Communication
Wordlist: 10 (Digits) Captcha 4 digits Chrome Solver 99.95 % 1956 / 1957 Only 10k captchas possible Play me
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Automated Training Yo dawg, we heard you like Artificial Intelligence, so we put some Genetic Algorithms in your Machine Learning, so you can evolve while you're training
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Genetic Algorithms Trainer
Test The NN Child Is Better Child Is Worse Combine with Previous Set B and Sort by Certainty Solve Set B Words Using Theta A Train the NN On the Best X% Download Captchas Split Captchas Combine with Previous Set A and Sort by Certainty Child Is Better Solve Set A Words Using Theta B Train the NN On the Best X% Child Is Worse Test The NN
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Experiment Paypal 31 letters (1 of each possible output)
Before: 12% Accuracy After: 48% Accuracy
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Code Release Yes, We're Releasing Everything!
All The Code Theta Values
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Seriously Google Let's have some drinks
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Questions?
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Contact Stiltwalker@dc949.org Adam adam@dc949.org @adamOfDc949 C-P
@cps_rants Jeffball @jeffball55
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