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public:papers:acsac2017 [2017-12-04 20:54]
xnemec1 [Q&A section]
public:papers:acsac2017 [2017-12-08 17:36] (current)
xnemec1 [Measuring Popularity of Cryptographic Libraries in Internet-Wide Scans [ACSAC 2017]]
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   * Conference page: [[https://www.acsac.org/2017/ | ACSAC 2017]] | [[https://www.acsac.org/2017/openconf/modules/request.php?module=oc_program&action=summary.php&id=106 | Paper page]]   * Conference page: [[https://www.acsac.org/2017/ | ACSAC 2017]] | [[https://www.acsac.org/2017/openconf/modules/request.php?module=oc_program&action=summary.php&id=106 | Paper page]]
   * Download author pre-print of the paper: {{ :public:papers:acsac2017_nemec_rsa_fingerprints.pdf | pdf}}   * Download author pre-print of the paper: {{ :public:papers:acsac2017_nemec_rsa_fingerprints.pdf | pdf}}
-  * Download presentation: {{ fixme | pdf}}+  * Download presentation: {{ :public:papers:acsac-nemec-handout.pdf Handout-PDF}} | {{ :public:papers:acsac-nemec.pdf | Conference-PDF }}
  
 **Bibtex (regular paper)** **Bibtex (regular paper)**
  
   @inproceedings{2017-acsac-nemec,   @inproceedings{2017-acsac-nemec,
-    Author        = {Matus Nemec and Dusan Klinec and Petr Svenda and Peter Sekan and Vashek Matyas}, +    author = {Nemec, Matus and Klinec, Dusan and Svenda, Petr and Sekan, Peter and Matyas, Vashek}, 
-    Title         = {Measuring Popularity of Cryptographic Libraries in Internet-Wide Scans}, +    title = {Measuring Popularity of Cryptographic Libraries in Internet-Wide Scans}, 
-    BookTitle     = {Proceedings of the 33rd Annual Computer Security Applications Conference (ACSAC'2017)}, +    booktitle = {Proceedings of the 33rd Annual Computer Security Applications Conference}, 
-    Year          = {2017}, +    series = {ACSAC 2017}, 
-    Pages         = {??--??}, +    year = {2017}, 
-    ISBN          = {??}, +    isbn = {978-1-4503-5345-8}, 
-    Publisher     = {ACM}+    pages = {162--175}, 
 +    url = {http://doi.acm.org/10.1145/3134600.3134612}, 
 +    doi = {10.1145/3134600.3134612}, 
 +    publisher = {ACM}
   }   }
  
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 ==Q: Does it mean the biased RSA key generation methods are broken?== ==Q: Does it mean the biased RSA key generation methods are broken?==
-A: No, in general, the bias is not enough for key factorization. However, we did break the Infineon implementation in our recent paper [[https://crocs.fi.muni.cz/public/papers/rsa_ccs17 | The Return of Coppersmith's Attack (ROCA)]]+A: No, in general, the bias is not enough for key factorization. However, we did break the Infineon implementation in our recent paper [[https://crocs.fi.muni.cz/public/papers/rsa_ccs17 | The Return of Coppersmith's Attack (ROCA)]]
 + 
 +==Q: What parts of an RSA public key are biased?== 
 +A: We extract an 8-bit feature vector from a public modulus N: we use the remainder of division of the modulus N modulo 3, remainder modulo 4, and the 2nd to 7th most significant bits of the modulus. 
 + 
 +{{:public:papers:acsac2017_explain_mask_openssl.png?400|}} 
 + 
 +==Q: What was the motivation for the measurement?== 
 +A: We developed a method for probabilistic classification of keys based on their source in our paper [[https://crocs.fi.muni.cz/public/papers/usenix2016 | The Million-Key Question]] at [[https://www.usenix.org/node/197198 | USENIX Security 2016]]. However, we were missing an accurate estimation of library popularity and could not find any papers accomplishing that. We also needed to measure the impacts of [[https://crocs.fi.muni.cz/public/papers/rsa_ccs17 | ROCA vulnerability]] and this is a general method for such measurements.
  
 ==Q: What libraries did you analyze? Can you tell all libraries apart?== ==Q: What libraries did you analyze? Can you tell all libraries apart?==
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 {{:public:papers:acsac2017_dendrogram.png?600|}} {{:public:papers:acsac2017_dendrogram.png?600|}}
 +
 +==Q: Does popularity of libraries change in time?==
 +A: Yes, for one, the number of OpenSSL keys increases significantly.
 +{{:public:papers:acsac2017_intime.png?800|}}
  
 ==Q: I want to know the popularity of library X, why wasn't it included? == ==Q: I want to know the popularity of library X, why wasn't it included? ==
-A: To suggest other sources that we can add to our analysis, please get in touch with us. If you can also provide keys generated by hardware, open-source and proprietary libraries, we will add them to the [[https://drive.google.com/drive/u/3/folders/0B0PpUrsKytcyMllkUHJ0RkZkdzA | Collection of RSA keys from reference libraries]]+A: To suggest other sources that we can add to our analysis, please get in touch with us. If you can also provide keys generated by hardware, open-source and proprietary libraries, we will add them to the [[https://drive.google.com/drive/u/3/folders/0B0PpUrsKytcyMllkUHJ0RkZkdzA | Collection of RSA keys from reference libraries]]
 + 
 +==Q: Why can't you associate a key with its source with certainty?== 
 +A: The features extracted from the keys are not unique. Different (groups of) libraries can produce keys with the same features. Only the distribution of the features differs, as illustrated here: 
 + 
 +{{:public:papers:acsac2017_reference.png?800|}}
  
 +==Q: What is the accuracy of the measurement?==
 +A: We performed simulations to determine the accuracy. The expected error of the measurement was within 1 percentage point of the estimation (e.g., OpenSSL being estimated at 70% means that we expect it to be between 69% and 71%). The error might be larger in some cases, however the ground truth is not always known. Our estimation of ROCA vulnerable keys in a PGP dataset was at 0.10%, that is within 0.02 percentage points from the correct proportion found by a much more reliable method specific to the ROCA keys.