Cryptography for Rails Developers

Given at Rails Israel 2014

Transcript

1. Cryptography for Rails Developers
2. Christopher Rigor @crigor
5. An open ball is open
6. 1. Public-key Cryptography
7. 2. SSL / TLS
8. 3. Tips for Rails Applications
10. Symmetric-key Cryptography
11. One key to encrypt and decrypt
12. "hello"
13. ciphertext
14. Public-key Cryptography
15. public key to encrypt private key to decrypt
16. privatekeycheck.com
17. Why on earth would you post it here? Now it's surely not.
18. RSA
19. 3 numbers e, n, and d
20. e = public key n = public key d = private key
21. end
22. "en"crypt "d"ecrypt
23. e = 17 n = 3233 d = 2753
25. 42 ** e % n
26. 42 ** e % n 42 ** 17 % 3233 2557
28. "d"ecrypt
29. 2557 ** d % n
30. 2557 ** d % n 2557 ** 2753 % 3233 42
31. n = product of 2 prime numbers
32. e = usually 65537
34. e = 65537
35. d = computed from e, prime1 and prime2
36. e = public n = public d = private prime numbers = private
38. -----BEGIN RSA PRIVATE KEY----- MIIEogIBAAKCAQEAwJ5g2RhxbKWq3PeS5EUIwemy1sYffQwn reUzryNwoB9/hqt0 NPAtq2vQftuko39VKw1hrpnk08bXWPqsN38HR9421q +nd0dgY1sG8EljSeG3dGvP 4rZ1EgUbac4WDAKvA+fhiebg4QS2bAaB9IEL +3rjQRhNsvaYgI2K3AHePbFVq0ut 6Ey0WwN4m/yf8JYerJWPlHLyU8W4xtyHExuX/IK4g6Uf8Z9Av +WiK8mfHaw7Kge/ EO1UAGWOrd7RLx3A2WjOU7d0KtrshU1r64Xl4m1/ JbHQYBGkzYS0Mm7hhI5mnN/t 8h1hW2TksiVHrZ8rjOoYOrlkZOpVUwf7s2LYVQIDAQABAoIBA
39. publicExponent: 65537 (0x10001)
40. modulus: 00:c0:9e:60:d9:18:71:6c:a5:aa:dc:f7:92:e 08:c1:e9:b2:d6:c6:1f:7d:0c:27:ad:e5:33:a 70:a0:1f:7f:86:ab:74:34:f0:2d:ab:6b:d0:7 a4:a3:7f:55:2b:0d:61:ae:99:e4:d3:c6:d7:5 ac:37:7f:07:47:de:36:d6:af:a7:77:47:60:6 06:f0:49:63:49:e1:b7:74:6b:cf:e2:b6:75:1 1b:69:ce:16:0c:02:af:03:e7:e1:89:e6:e0:e b6:6c:06:81:f4:81:0b:fb:7a:e3:41:18:4d:b 98:80:8d:8a:dc:01:de:3d:b1:55:ab:4b:ad:e b4:5b:03:78:9b:fc:9f:f0:96:1e:ac:95:8f:9 f2:53:c5:b8:c6:dc:87:13:1b:97:fc:82:b8:8 1f:f1:9f:40:bf:e5:a2:2b:c9:9f:1d:ac:3b:2 bf:10:ed:54:00:65:8e:ad:de:d1:2f:1d:c0:d
41. 2431585381023245243664330467172106030832010383116 4469677832495734668099074396651844271258357540051 3767266433204751301161494548152938586277693179979 9890466216086685504686094092324062775361449344083 8874077885512524472300856401934110431460528205155 8296721167524104278478378503629406922274058522565 4049522376109500926733651743749347006963603460324 4750405711451831483661181796223823470036752363791 8444923562030168749604532593343488635664366782360 4357641224346337617299750469531547237002599501779 0644182536453093727509649248024164911346045419437 5737979721222481332470495918510303683249090717606
42. privateExponent: 33:ed:7e:a6:88:54:6b:b9:ed:ea:4c:44:29:8 e2:64:22:76:8c:4b:08:e7:31:fb:4b:83:37:8 68:d8:95:04:b5:4c:4a:c9:45:46:a5:76:3b:f d1:b1:0e:40:e1:06:a8:8f:8c:85:1b:62:0a:f 5e:bc:bc:35:bf:ce:80:ea:31:f7:92:22:86:2 24:4f:64:99:12:64:e6:d9:f9:dd:60:db:06:d a3:50:8f:d9:05:10:31:b9:5d:b0:53:b1:e4:7 c6:12:ab:0e:43:8b:fb:6c:11:c0:06:d1:4b:a 53:10:d5:92:a2:5e:4b:ba:fe:e0:90:a6:17:4 d3:1d:8e:f7:e6:64:a6:85:34:0e:87:b0:3b:b 90:2a:b4:62:08:f3:fd:42:d8:73:e2:2d:54:1 5c:9c:6f:16:7f:d2:1f:8e:51:c5:14:12:91:b 7e:34:14:e0:db:79:ee:05:45:22:de:3b:99:5
43. 6555266568796053674269708820055353365692655972794 2055673580501799001476180850518758042722837636392 8351933006067037854787568194571939353701616354713 5887324275725095670658393033428680152446112426762 6108489567913588106964238660508089034140197495871 5227500433009731051490912217850124586529451451345 8923502958802219960425895673146838867589769393986 0556673632421808148038002771480134566168093718746 0473165736741978268341806296994087055044759829337 3573899404839955835464081022920152659481994084458 0520520598913413928409545239844803823479590208225 3984444016315990695698402100055840447044896509668
44. 42 ** e % n
45. 7403918762823839092797670141313950212528994606053 3799517843086878229299923652258151711100231746381 6181786944539511010243166014190260358058104908205 7304340698199082430151945214069936900404923317185 5875418936265830788037850186423336723791573716176 6591077359161448282606674296267688726733192810543 3908133856731992683370184186601764915219096941742 8143523889081093181350050901295990484830674004492 0001520753653244602808387141190318409556217244506 4939370112341529423864414627775025027597348907780 1135695002049594281938966058393001384364228739328 6572785551769536889192869044823881149520366525399
46. c ** d % n c = ciphertext d = private key n = modulus
47. warning: in a**b, b may be too big => NaN
48. python
49. # ruby 42 ** e % n # python pow(42, e, n)
50. 7403918762823839092797670141313950212528994606053 3799517843086878229299923652258151711100231746381 6181786944539511010243166014190260358058104908205 7304340698199082430151945214069936900404923317185 5875418936265830788037850186423336723791573716176 6591077359161448282606674296267688726733192810543 3908133856731992683370184186601764915219096941742 8143523889081093181350050901295990484830674004492 0001520753653244602808387141190318409556217244506 4939370112341529423864414627775025027597348907780 1135695002049594281938966058393001384364228739328 6572785551769536889192869044823881149520366525399
51. pow (c, d, n)
53. require "openssl" c.to_bn.mod_exp(d,n)
54. RECAP
55. SSL / TLS
56. HTTPS
59. 1995 - SSLv2 1996 - SSLv3 1999 - TLSv1 2006 - TLSv1_1 2008 - TLSv1_2
61. 1. Server sends the public key 2. Browser encrypts shared key
62. DES RC4 AES
63. BEAST
64. BEAST (SSLv3, TLSv1) (DES, AES)
65. POODLE (SSLv3) (DES, AES)
66. Heartbleed
67. TLS 1.2, AES-GCM
68. 1. Server sends the public key (RSA) 2. Browser encrypts shared key (RSA) 3. Browser encrypts data (AES-GCM)
69. 1. Server sends the public key (RSA) 2. Browser encrypts shared key (RSA ECDHE) 3. Browser encrypts data (AES-GCM)
70. PERFECT FORWARD SECRECY
71. TLS 1.2, AES-GCM, ECDHE
72. Rails
73. do not use SSLv3
74. do not set ssl_version to TLSv1
75. set it to SSLv23
76. OpenSSL::SSL::OP_NO_SSLv3
77. 2.1.4 2.0.0-p594 1.9.3-p550
78. VERIFY_PEER
79. ActiveSupport::MessageEncryptor
80. key = Rails.configuration.secretkeybase crypt = ActiveSupport::MessageEncryptor.new(key) encrypteddata = crypt.encryptand_sign("my confidental data")
81. salt = SecureRandom.randombytes(64) key = ActiveSupport::KeyGenerator.new('password').generatekey(salt )
82. RbNacl
83. key = RbNaCl::Random.random_bytes(RbNaCl::SecretBox.key_bytes ) box = RbNaCl::SimpleBox.fromsecretkey(key) box.encrypt("my confidental data")
84. RECAP
85. Thank you crigor@engineyard.com @crigor
86. Resources https://www.flickr.com/photos/delgrossodotcom/3211643440 https://www.flickr.com/photos/ twosevenoneonenineeightthreesevenatenzerosix/6655759625 https://www.flickr.com/photos/nox_noctis_silentium/ 6315616870 https://www.flickr.com/photos/orqwith/2059728917 https://www.flickr.com/photos/37467370@N08/7606239970 https://www.flickr.com/photos/ul_marga/755378645 https://www.flickr.com/photos/richard-g/3549285383
87. https://www.flickr.com/photos/brenda-starr/3509344100 https://www.flickr.com/photos/ 120600995@N07/14028600474 https://www.flickr.com/photos/13519089@N03/1380483002 https://www.flickr.com/photos/danielproulx/3426805996 https://www.flickr.com/photos/chrisinplymouth/4262775481 https://www.flickr.com/photos/chrisinplymouth/4117583864 https://www.flickr.com/photos/danielfoster/14758510078 https://www.flickr.com/photos/gamikun/2564208746 https://www.flickr.com/photos/nathaninsandiego/9339787996 https://www.flickr.com/photos/dashupagla/2519031536 https://www.flickr.com/photos/imagesbywestfall/435