Transcript 技巧很強壯的大叔隊Introduction

Captcha Breaker
GPGPU final project proposal
技巧很強壯的大叔隊
羅際巧 (技巧)
陳群元 (強壯)
廖航緯 (大叔)
技巧很強壯的大叔隊
Introduction
Captcha: Completely Automatic Public Turing Test to Tell Computers and
Humans Apart (全自動分辨人機的圖靈測試...)
太長了...所以就簡稱 "驗證碼"...
CAPTCHA 這個詞最早是在2002年由卡內基梅隆大學的Luis von Ahn、Manuel
Blum、Nicholas J.Hopper以及IBM的John Langford所提出。
Turing Test:
Captcha:
Introduction
Google買下reCaptcha, 是因為知道Captcha可以"一魚兩吃"
1. Stop Spam : 阻止垃圾資訊(ex: 帳號, 郵件)流動在網路中
2. Read Books : 提昇google文件OCR(光學文字辨識)正確率
我們的Project，就是要運用GPU的運算能力來破解驗證碼
Captcha Breaker:
System Architecture
Input captcha
preprocessing
segmentation
Recognition
Over looks
inquiry
Segmentation
• Gray image
• Image clean up
– Erosion, dilation, arc remove…etc
• Text pixel identification
– threshold
• Color filling
• K-means
Optical Character Recognition
• Template matching
• Genetic Algorithm for template/pattern learning
• Dictionary attack
Time line
5/15
Segment parallel
Segment sequential
5/5
6/05
OCR parallel
OCR sequential
5/25
Any Question?
Some References
• Algorithm To Break Visual CAPTCHA
• Algorithm for secured online authentication
using CAPTCHA
• Reverse Engineering CAPTCHAs
• Bio-inspired unified model of visual
segmentation system for captcha character
recognition