R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts ›...
Transcript of R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts ›...
![Page 1: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/1.jpg)
R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T. Ristenpart
![Page 2: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/2.jpg)
Password checking systems and typos
![Page 3: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/3.jpg)
Typo-tolerance improves utility
![Page 4: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/4.jpg)
… corrects only the tip of the iceberg
![Page 6: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/6.jpg)
Adaptive typo-tolerance
☺
If only we could store passwords in plaintext…
![Page 7: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/7.jpg)
![Page 8: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/8.jpg)
Simulate password typing behavior at
••
•
![Page 9: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/9.jpg)
![Page 10: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/10.jpg)
Register
𝑠𝑘, 𝑝𝑘
E 𝑠𝑘
𝑝𝑘
(E, D):
E( 𝑠𝑘):𝑘 ← PBKDF( )𝐶 ← AEnc (𝑘, 𝑠𝑘
𝐶
Design of TypTop : Registration
𝑝𝑘
![Page 11: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/11.jpg)
Design of TypTop : Login
𝑝𝑘
E 𝑠𝑘
D( ) ≠ ⊥
E 𝑠𝑘 𝑝𝑘 𝑝𝑘
![Page 12: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/12.jpg)
Design of TypTop : Login
𝑝𝑘
E 𝑠𝑘E 𝑠𝑘
D( ) ≠ ⊥
E 𝑠𝑘
𝑝𝑘
𝑠𝑘
𝑠𝑘
𝑝𝑘
![Page 13: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/13.jpg)
Design of TypTop : Login with a typo
𝑝𝑘
E 𝑠𝑘
E 𝑠𝑘
☺𝑝𝑘
![Page 14: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/14.jpg)
Design of TypTop : Some more details
𝑝𝑘
E 𝑠𝑘
E 𝑠𝑘
ラβτ
了й وا 随وا
τυχкলشન્ડش# βτᶉ ᶆ
• zxcvbn
𝑝𝑘
![Page 15: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/15.jpg)
![Page 16: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/16.jpg)
•
•
•
![Page 17: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/17.jpg)
Smash and grab attack (Offline attack)
了й وا 随وا
𝑝𝑘
E 𝑠𝑘
E 𝑠𝑘
βτᶉ ᶆ
𝑝𝑘
𝑝𝑘
𝑝𝑘
![Page 18: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/18.jpg)
Obvious strategy is the best an attacker can do
≅
![Page 19: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/19.jpg)
TypTop’s state appears random
≅
⇒
έ
𝑝𝑘
ṓɲṩḙ ᶒ रें
ɖ ƥभ ṩ ɳ ɾ
ᵯ ꞡᶇ ⱡ ɋṹ值β
填写随机
بے ترتیب اقدار 𝑝𝑘Ɖر
了й وا 随وا
𝑝𝑘
E 𝑠𝑘
E 𝑠𝑘
βτᶉ ᶆ
𝑝𝑘
𝑝𝑘
𝑝𝑘
![Page 20: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/20.jpg)
E 𝑠𝑘
E 𝑠𝑘
βτᶉ ᶆ
Guessing against the cache entries
![Page 21: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/21.jpg)
Guessing typo is beneficial if…
![Page 22: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/22.jpg)
t-Sparse
t-sparse:
∀𝑤,
𝑤
ǁ𝜏𝑤 𝑤 ≤ 𝑡𝑤𝑤𝑡ǁ𝜏𝑤
ǁ𝜏𝑤ǁ𝜏𝑤(𝑤) = Pr 𝑤 in cache 𝑤],
![Page 23: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/23.jpg)
t-Sparse ⇒ TypTop ≡ Normal Pw checker
𝐼𝑓 𝑡𝑦𝑝𝑜 𝑑𝑖𝑠𝑡𝑟𝑖𝑏𝑢𝑡𝑖𝑜𝑛 𝑖𝑠 𝑡 𝑠𝑝𝑎𝑟𝑠𝑒 𝑢𝑛𝑑𝑒𝑟 𝑇𝑦𝑝𝑇𝑜𝑝 𝑠𝑐𝑎𝑐ℎ𝑖𝑛𝑔 𝑝𝑜𝑙𝑖𝑐𝑦 𝑡ℎ𝑒𝑛 𝑏𝑒𝑠𝑡 𝑎𝑡𝑡𝑎𝑐𝑘 𝑖𝑠 𝑡𝑜 𝑏𝑟𝑢𝑡𝑒 𝑓𝑜𝑟𝑐𝑒𝑔𝑢𝑒𝑠𝑠 𝑡ℎ𝑒 𝑟𝑒𝑔𝑖𝑠𝑡𝑒𝑟𝑒𝑑 𝑝𝑎𝑠𝑠𝑤𝑜𝑟𝑑
![Page 24: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/24.jpg)
Guessing typo is sub-optimal if t-sparse
E 𝑠𝑘
E 𝑠𝑘
βτᶉ ᶆ
E 𝑠𝑘
E 𝑠𝑘
βτᶉ ᶆ
≤
![Page 25: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/25.jpg)
Attacking TypTop is no easier than attacking traditional password checkers
t-sparse
≅
![Page 26: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/26.jpg)
![Page 27: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/27.jpg)
TypTop: a smart password checker for Unix
•
•
•
•
•
A smart password checker that lets you make mistakes
![Page 28: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/28.jpg)
TypTop pilot deployment study
••
•
•
![Page 29: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/29.jpg)
TypTop in one slide
•
•
•
Typo-tolerant password checking might encourage users to adopt better security practices
![Page 30: R. Chatterjee, J. Woodage, Y. Pnueli, A. Chowdhury, T ... › ~chatterjee › ppts › typtop_CCS2017.pdf · Design of TypTop: Some more details 𝑝𝑘 E 𝑘 E 𝑘 ラβτ 了й](https://reader033.fdocuments.us/reader033/viewer/2022060209/5f043df57e708231d40d02bd/html5/thumbnails/30.jpg)