Cryptography at GoGaRuCo 2012

Video available at http://confreaks.com/videos/1114-gogaruco2012-modern-cryptography

Transcript

1. MODERN CRYPTOGRAPHY John Downey | @jtdowney
2. • John Downey • Developer at Braintree • Payment Gateway • We’re hiring
3. http://www.flickr.com/photos/60445767@N00/2466272019/
4. http://www.flickr.com/photos/freefoto/5692512457/
5. http://www.flickr.com/photos/zappowbang/2049368918/
6. http://www.flickr.com/photos/katieharbath/4382294246/
7. http://www.flickr.com/photos/kalebdf/2170180285/
8. http://www.flickr.com/photos/alstonfamily/2237347597/
10. http://www.flickr.com/photos/damiavos/4707651586/
11. http://www.flickr.com/photos/bootycat/5849904501/
12. •For data in transit •Use TLS/SSL, SSH, or VPN •For data at rest •Use GnuPG
13. http://www.flickr.com/photos/alancleaver/4121423119/
14. http://www.flickr.com/photos/proimos/4199675334/
15. RANDOM NUMBER GENERATION
16. http://www.flickr.com/photos/brentnewhall/6559793329/
18. MD_Update(&m,buf,j);
19. Don't add uninitialised data to the random number generator. This stop valgrind from giving error messages in unrelated code. (Closes: #363516)
20. /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */ MD_Update(&m,buf,j); /* We know that line may cause programs such as purify and valgrind to complain about use of uninitialized data. The problem is not, it's with the caller. Removing that line will make sure you get really bad randomness and thereby other problems such as very insecure keys. */
21. RECOMMENDATIONS • Use the crypto library RNG • SecureRandom • OpenSSL::Random • On Linux (or other Unix-like OS) • /dev/random - blocks for entropy • /dev/urandom - non-blocking
22. LENGTH EXTENSION ATTACKS
23. HASH FUNCTIONS
24. http://www.flickr.com/photos/littlejohncollection/3675547973/
25. USCYBERCOM plans, coordinates, integrates, synchronizes and conducts activities to: direct the operations and defense of specified Department of Defense information networks and; prepare to, and when directed, conduct full spectrum military cyberspace operations in order to enable actions in all domains, ensure US/Allied freedom of action in cyberspace and deny the same to our adversaries. 9EC4C12949A4F31474F299058CE2B22A MD5
27. RECOMMENDATIONS •Use SHA-256 (SHA-2 family) •Stop using MD5 and SHA1
28. RestClient.post( 'http://example.com/things', :name => 'Widget', :price => 1_23, :signature => signature )
29. secret = "api-key" str = "name=#{name}&" str += "price=#{price}" body = "#{secret}|#{str}" signature = sha1(body)
30. http://www.flickr.com/photos/worldbank/3492662794/
31. h0 = 0x8CBBCB20 h1 = 0x4861672F h2 = 0x93B26A64 h3 = 0x01E68519 h4 = 0x5AB5719B h0 = 0x67452301 h1 = 0xEFCDAB89 h2 = 0x98BADCFE h3 = 0x10325476 h4 = 0xC3D2E1F0
32. h0 = 0x8CBBCB20 h1 = 0x4861672F h2 = 0x93B26A64 h3 = 0x01E68519 h4 = 0x5AB5719B 8CBBCB204861672F93B26A6401E685195AB5719B
33. sha1("api-key|name=Widget&price=123") 8CBBCB204861672F93B26A6401E685195AB5719B SHA1
34. &price=0
35. api-key|name=Widget&price=123&price=0
36. h0 = 0x8CBBCB20 h1 = 0x4861672F h2 = 0x93B26A64 h3 = 0x01E68519 h4 = 0x5AB5719B h0 = 0x7CA17A2B h1 = 0x91BD35C0 h2 = 0x9D50A3AD h3 = 0x5CAD1E9B h4 = 0x396DDEF4
37. api-key|name=Widget&price=123&price=0 7CA17A2B91BD35C09D50A3AD5CAD1E9B396DDEF4 SHA1
38. RestClient.post( 'http://example.com/things', :name => 'Widget', :price => 0, :signature => signature )
39. RECOMMENDATIONS •Use HMAC-SHA-256 for authentication •Keyed hash function •Resistant to length extension
40. PASSWORD STORAGE
41. http://www.flickr.com/photos/sponng/4554602341/
47. sha1(password)
48. 1.One-way •Only useful for verification
49. sha1(salt + password)
50. 1.One-way •Only useful for verification 2.Randomized •Defeats pre-computed tables •Forces focus on one password
51. http://www.flickr.com/photos/jaffathecake/2618896075/
52. 1.One-way •Only useful for verification 2.Randomized •Defeats pre-computed tables •Forces focus on one password 3.Slow
53. bcrypt, scrypt, or PBKDF2 ADAPTIVE HASHING
54. RECOMMENDATIONS • Delegate authentication if possible • Facebook, Twitter, Google, Github • Store one-way verifiers using bcrypt, scrypt, or PBDKF2 • Use existing framework • has_secure_password (Rails >= 3.1) • devise
55. TRUST
56. The authenticity of host 'apollo.local (10.0.2.56)' can't be established. RSA key fingerprint is 04:63:c1:ba:c7:31:04:12:14:ff:b6:c4:32:cf:44:ec. Are you sure you want to continue connecting (yes/no)?
57. @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that the RSA host key has just been changed. The fingerprint for the RSA key sent by the remote host is 04:63:c1:ba:c7:31:04:12:14:ff:b6:c4:32:cf:44:ec. Please contact your system administrator.
58. • AOL Time Warner Inc. • AS Sertifitseerimiskeskus • AddTrust • Baltimore • beTRUSTed • Buypass • CNNIC • COMODO CA Limited • Certplus • certSIGN • Chambersign • Chunghwa Telecom Co., Ltd. • ComSign • Comodo CA Limited • Cybertrust, Inc • Deutsche Telekom AG • Deutscher Sparkassen Verlag GmbH • Dhimyotis • DigiCert Inc • DigiNotar • Digital Signature Trust Co. • Disig a.s. • EBG Bilişim Teknolojileri ve Hizmetleri A.Ş. • EDICOM • Entrust, Inc. • Equifax • GTE Corporation • GeoTrust Inc. • GlobalSign nv-sa • Hongkong Post • Japan Certification Services, Inc. • Japanese Government • Microsec Ltd. • NetLock Halozatbiztonsagi Kft. • Network Solutions L.L.C. • PM/SGDN • QuoVadis Limited • RSA Security Inc • SECOM Trust Systems CO.,LTD. • SecureTrust Corporation • Sociedad Cameral de Certificación Digital • Sonera • Staat der Nederlanden • Starfield Technologies, Inc. • StartCom Ltd. • SwissSign AG • Swisscom • TC TrustCenter GmbH • TDC • Taiwan Government • Thawte • The Go Daddy Group, Inc. • The USERTRUST Network • TÜBİTAK • TÜRKTRUST • Unizeto Sp. z o.o. • VISA • ValiCert, Inc. • VeriSign, Inc. • WISeKey • Wells Fargo • XRamp Security Services Inc
59. KRYPT https://github.com/krypt
60. • Videos • Theory and Practice of Cryptography series • http://www.youtube.com/watch?v=IzVCrSrZIX8 • http://www.youtube.com/watch?v=KDvt_0cafPw • http://www.youtube.com/watch?v=YcgqBEzcD_I • http://www.youtube.com/watch?v=ZDnShu5V99s • Crypto Strikes Back! • http://www.youtube.com/watch?v=ySQl0NhW1J0 • Presentations • http://www.bsdcan.org/2010/schedule/attachments/135_crypto1hr.pdf • http://www.eff.org/files/DefconSSLiverse.pdf • Books • Cryptography Engineering - Ferguson, Schneier, and Kohno • Blogs • http://blog.cryptographyengineering.com/ • http://rdist.root.org/
61. QUESTIONS? John Downey | @jtdowney