Alice & Bob: Public key cryptography 101 - Mail.ru techforum 2012

Transcript

1. Alice & Bob Mail.ru techforum - 24 april 2012 Moskow - Russia Public key cryptography 101 woensdag 25 april 12
2. Joshua Thijssen / Netherlands Freelance consultant, developer and trainer @ NoxLogic / Techademy Development in PHP, Python, Perl, C, Java.... Blog: http://adayinthelifeof.nl Email: jthijssen@noxlogic.nl Twitter: @jaytaph 2 woensdag 25 april 12
3. An introduction into public key cryptography 3 woensdag 25 april 12
4. 4 Without this there would be no internet as we know today (really) woensdag 25 april 12
5. 5 woensdag 25 april 12
6. Meet Alice, 5 woensdag 25 april 12
7. Meet Alice, and Bob. 5 Hi Bob! Hello Alice! woensdag 25 april 12
8. “bad” encryption algorithms 6 http://www.flickr.com/photos/dpwk/1714014449/in/pool-1621478@N23/ woensdag 25 april 12
9. “algorithm”: A = 1, B = 2, C = 3, ...., Z = 26 ‣ SUBSTITUTION SCHEME 7 woensdag 25 april 12
10. ciphertext: 19, 5, 3, 18, 5, 20 “algorithm”: A = 1, B = 2, C = 3, ...., Z = 26 ‣ SUBSTITUTION SCHEME 7 woensdag 25 april 12
11. ciphertext: 19, 5, 3, 18, 5, 20 “algorithm”: A = 1, B = 2, C = 3, ...., Z = 26 = S E C R E T ‣ SUBSTITUTION SCHEME 7 woensdag 25 april 12
12. 8 ‣ SUBSTITUTION SCHEME woensdag 25 april 12
13. 8 ciphertext:  ‣ SUBSTITUTION SCHEME woensdag 25 april 12
14. 8 ciphertext:  = W I N G D I N G S ‣ SUBSTITUTION SCHEME woensdag 25 april 12
15. “algorithm”: c = m + k mod 26 ‣ CAESARIAN CIPHER or CAESARIAN SHIFT 9 http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg woensdag 25 april 12
16. “algorithm”: c = m + k mod 26 ‣ CAESARIAN CIPHER or CAESARIAN SHIFT 9 Message: C O D E http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg woensdag 25 april 12
17. “algorithm”: c = m + k mod 26 ‣ CAESARIAN CIPHER or CAESARIAN SHIFT 9 Message: C O D E Ciphertext (key=1): D P E F http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg woensdag 25 april 12
18. “algorithm”: c = m + k mod 26 ‣ CAESARIAN CIPHER or CAESARIAN SHIFT 9 Message: C O D E Ciphertext (key=1): D P E F Ciphertext (key=2): E Q F G http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg woensdag 25 april 12
19. “algorithm”: c = m + k mod 26 ‣ CAESARIAN CIPHER or CAESARIAN SHIFT 9 Message: C O D E Ciphertext (key=1): D P E F Ciphertext (key=2): E Q F G Ciphertext (key=-1): B M C D http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg woensdag 25 april 12
20. “algorithm”: c = m + k mod 26 ‣ CAESARIAN CIPHER or CAESARIAN SHIFT 9 Message: C O D E Ciphertext (key=1): D P E F Ciphertext (key=2): E Q F G Ciphertext (key=-1): B M C D Ciphertext (key=0): C O D E http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg woensdag 25 april 12
21. “algorithm”: c = m + k mod 26 ‣ CAESARIAN CIPHER or CAESARIAN SHIFT 9 Message: C O D E Ciphertext (key=1): D P E F Ciphertext (key=2): E Q F G Ciphertext (key=-1): B M C D Ciphertext (key=0): C O D E Ciphertext (key=26): C O D E http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg woensdag 25 april 12
22. “algorithm”: c = m + k mod 26 ‣ CAESARIAN CIPHER or CAESARIAN SHIFT 9 Message: C O D E Ciphertext (key=1): D P E F Ciphertext (key=2): E Q F G Ciphertext (key=-1): B M C D Ciphertext (key=0): C O D E Ciphertext (key=26): C O D E Ciphertext (key=52): C O D E http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg woensdag 25 april 12
23. ‣ FLAWS IN THESE CIPHERS 10 woensdag 25 april 12
24. ➡ Key is too easy to guess. ‣ FLAWS IN THESE CIPHERS 10 woensdag 25 april 12
25. ➡ Key is too easy to guess. ➡ Key has to be send to Bob. ‣ FLAWS IN THESE CIPHERS 10 woensdag 25 april 12
26. ➡ Key is too easy to guess. ➡ Key has to be send to Bob. ➡ Deterministic. ‣ FLAWS IN THESE CIPHERS 10 woensdag 25 april 12
27. ➡ Key is too easy to guess. ➡ Key has to be send to Bob. ➡ Deterministic. ➡ Prone to frequency analysis. ‣ FLAWS IN THESE CIPHERS 10 woensdag 25 april 12
28. 11 woensdag 25 april 12
29. ➡ The usage of every letter in the English (or any other language) can be represented by a percentage. 11 woensdag 25 april 12
30. ➡ The usage of every letter in the English (or any other language) can be represented by a percentage. ➡ ‘E’ is used 12.7% of the times in english texts, the ‘Z’ only 0.074%. 11 woensdag 25 april 12
31. ➡ The usage of every letter in the English (or any other language) can be represented by a percentage. ➡ ‘E’ is used 12.7% of the times in english texts, the ‘Z’ only 0.074%. ➡ ‘O’ is used 11.07% of the times in russian texts, the ‘Ъ’ only 0.02%. 11 woensdag 25 april 12
32. http://www.gutenberg.org/cache/epub/14082/pg14082.txt Once upon a midnight dreary, while I pondered, weak and weary, Over many a quaint and curious volume of forgotten lore— While I nodded, nearly napping, suddenly there came a tapping, As of some one gently rapping—rapping at my chamber door. "'Tis some visitor," I muttered, "tapping at my chamber door— Only this and nothing more." 12 woensdag 25 april 12
33. A small bit of text can result in differences, but still there are some letters we can deduce.. ‣ “THE RAVEN”, FIRST PARAGRAPH 13 woensdag 25 april 12
34. We can deduce almost all letters just without even CARING about the crypto algorithm used. ‣ “THE RAVEN”, ALL PARAGRAPHS 14 woensdag 25 april 12
35. ‣ FLAWS IN THESE CIPHERS 15 woensdag 25 april 12
36. ➡ Determinism and the ability to use frequency analysis are “bad things” ‣ FLAWS IN THESE CIPHERS 15 woensdag 25 april 12
37. ‣ SYMMETRICAL ALGORITHMS 16 woensdag 25 april 12
38. ➡ Previous examples were symmetrical encryptions. ‣ SYMMETRICAL ALGORITHMS 16 woensdag 25 april 12
39. ➡ Previous examples were symmetrical encryptions. ➡ Same key is used for both encryption and decryption. ‣ SYMMETRICAL ALGORITHMS 16 woensdag 25 april 12
40. ➡ Previous examples were symmetrical encryptions. ➡ Same key is used for both encryption and decryption. ➡ Good symmetrical encryptions: AES, Blowfish, (3)DES ‣ SYMMETRICAL ALGORITHMS 16 woensdag 25 april 12
41. ‣ THE PROBLEM WITH SYMMETRICAL ALGORITHMS 17 woensdag 25 april 12
42. How does Alice send over the key securely to Bob? Everybody’s listening! ‣ THE PROBLEM WITH SYMMETRICAL ALGORITHMS 17 woensdag 25 april 12
43. Another encryption system: Asymmetrical encryption or public key encryption. 18 woensdag 25 april 12
44. Two keys instead of one: public key - available for everybody. Can be published on your blog. private key - For your eyes only! 19 woensdag 25 april 12
45. http://upload.wikimedia.org/wikipedia/commons/f/f9/Public_key_encryption.svg ‣ USES 2 KEYS INSTEAD OF ONE: A KEYPAIR 20 woensdag 25 april 12
46. It is NOT possible to decrypt the message with same key that is used to encrypt. 21 woensdag 25 april 12
47. Encrypt with public key: - only private key (thus Alice) can decrypt. - message is only for Alice = encryption 22 woensdag 25 april 12
48. Encrypt with public key: - only private key (thus Alice) can decrypt. - message is only for Alice = encryption 22 Encrypt with private key: - only public key can decrypt. - message is guaranteed coming for Alice = signing woensdag 25 april 12
49. Symmetrical ✓ quick. ✓ not resource intensive. ✓ useful for small and large messages. ✗ need to send over the key to the other side. Asymmetrical ✓ no need to send over the (whole) key. ✓ can be used for encryption and validation (signing). ✗ very resource intensive. ✗ only useful for small messages. 23 woensdag 25 april 12
50. Use symmetrical encryption for the (large) message and encrypt the key used with an asymmetrical encryption method. 24 woensdag 25 april 12
51. Hybrid ✓ quick ✓ not resource intensive ✓ useful for small and large messages ✓ safely exchange key data 25 woensdag 25 april 12
52. + http://www.zastavki.com/pictures/1152x864/2008/Animals_Cats_Small_cat_005241_.jpg Hybrid ✓ quick ✓ not resource intensive ✓ useful for small and large messages ✓ safely exchange key data 25 woensdag 25 april 12
53. But how does it work? 26 woensdag 25 april 12
54. RSA 27 woensdag 25 april 12
55. RSA Ron Rivest, Adi Shamir, Leonard Adleman 27 woensdag 25 april 12
56. RSA Ron Rivest, Adi Shamir, Leonard Adleman 27 1978 woensdag 25 april 12
57. RSA Ron Rivest, Adi Shamir, Leonard Adleman 27 1978 Pierre de Fermat, Leonard Euler 17th - 18th century woensdag 25 april 12
58. Public key encryption works on the premise that it is practically impossible to refactor a large number back into 2 separate prime numbers 28 woensdag 25 april 12
59. Public key encryption works on the premise that it is practically impossible to refactor a large number back into 2 separate prime numbers Prime number is only divisible by 1 and itself: 2, 3, 5, 7, 11, 13, 17, 19 etc... 28 woensdag 25 april 12
60. 29 woensdag 25 april 12
61. “large” number: 221 29 woensdag 25 april 12
62. “large” number: 221 but we cannot calculate its prime factors without brute force. There is no “formula” (like e=mc2) 29 woensdag 25 april 12
63. “large” number: 221 but we cannot calculate its prime factors without brute force. There is no “formula” (like e=mc2) (13 and 17) 29 woensdag 25 april 12
64. 30 woensdag 25 april 12
65. ➡ There is no proof that it’s impossible to refactor quickly (all tough it doesn’t look plausible) 30 woensdag 25 april 12
66. ➡ There is no proof that it’s impossible to refactor quickly (all tough it doesn’t look plausible) ➡ Brute-force decrypting is always lurking around (quicker machines, better algorithms). 30 woensdag 25 april 12
67. 31 The math behind the curtain woensdag 25 april 12
68. 32 woensdag 25 april 12
69. 32 ➡ p = (large) prime number woensdag 25 april 12
70. 32 ➡ p = (large) prime number ➡ q = (large) prime number (but not too close to p) woensdag 25 april 12
71. 32 ➡ p = (large) prime number ➡ q = (large) prime number (but not too close to p) ➡ n = p . q (bit length of the RSA key) woensdag 25 april 12
72. 32 ➡ p = (large) prime number ➡ q = (large) prime number (but not too close to p) ➡ n = p . q (bit length of the RSA key) ➡ φ = (p-1) . (q-1) (the φ thingie is called phi) woensdag 25 april 12
73. 32 ➡ p = (large) prime number ➡ q = (large) prime number (but not too close to p) ➡ n = p . q (bit length of the RSA key) ➡ φ = (p-1) . (q-1) (the φ thingie is called phi) ➡ e = gcd(e, φ) = 1 woensdag 25 april 12
74. 32 ➡ p = (large) prime number ➡ q = (large) prime number (but not too close to p) ➡ n = p . q (bit length of the RSA key) ➡ φ = (p-1) . (q-1) (the φ thingie is called phi) ➡ e = gcd(e, φ) = 1 ➡ d = (d . e) mod φ = 1 woensdag 25 april 12
75. Step 1: select primes P and Q ‣ P = ? | Q = ? | N = ? | Phi = ? | e = ? | d = ? 33 woensdag 25 april 12
76. Step 1: select primes P and Q ‣ P = 11 ‣ P = ? | Q = ? | N = ? | Phi = ? | e = ? | d = ? 33 woensdag 25 april 12
77. Step 1: select primes P and Q ‣ P = 11 ‣ Q = 3 ‣ P = ? | Q = ? | N = ? | Phi = ? | e = ? | d = ? 33 woensdag 25 april 12
78. Step 2: calculate N and Phi ‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34 woensdag 25 april 12
79. ➡ N = P . Q = 11 . 3 = 33 Step 2: calculate N and Phi ‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34 woensdag 25 april 12
80. ➡ N = P . Q = 11 . 3 = 33 ➡ φ = (11-1) . (3-1) = 10 . 2 = 20 Step 2: calculate N and Phi ‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34 woensdag 25 april 12
81. ➡ N = P . Q = 11 . 3 = 33 ➡ φ = (11-1) . (3-1) = 10 . 2 = 20 Step 2: calculate N and Phi ‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34 33 decimal is 100001 in binary == 6 bit key woensdag 25 april 12
82. ➡ N = P . Q = 11 . 3 = 33 ➡ φ = (11-1) . (3-1) = 10 . 2 = 20 Step 2: calculate N and Phi ‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34 There are 20 co primes for 33 : φ(33) = 20 33 decimal is 100001 in binary == 6 bit key woensdag 25 april 12
83. Step 3: find e ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = ? | d = ? 35 woensdag 25 april 12
84. Step 3: find e ‣ e = 3 ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = ? | d = ? 35 woensdag 25 april 12
85. Step 3: find e ‣ e = 3 ‣ gcd(e, φ) = 1 ==> gcd(3, 20) = 1 ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = ? | d = ? 35 woensdag 25 april 12
86. Step 3: find e ‣ e = 3 ‣ gcd(e, φ) = 1 ==> gcd(3, 20) = 1 ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = ? | d = ? 35 Fermat number: 2 + 1 2 n woensdag 25 april 12
87. Step 3: find e ‣ e = 3 ‣ gcd(e, φ) = 1 ==> gcd(3, 20) = 1 ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = ? | d = ? 35 Fermat number: 2 + 1 2 n Fermat prime: Fermat that is prime: 3, 5, 17, 257, 65537 Study shows that 98.5% of the time 65537 is used woensdag 25 april 12
88. ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = ? Step 4: find d 36 woensdag 25 april 12
89. ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = ? Step 4: find d ‣ Extended Euclidean Algorithm gives 7 36 woensdag 25 april 12
90. ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = ? Step 4: find d ‣ Extended Euclidean Algorithm gives 7 ‣ brute force: (e.d mod φ = 1) 36 woensdag 25 april 12
91. ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = ? Step 4: find d ‣ Extended Euclidean Algorithm gives 7 ‣ brute force: (e.d mod φ = 1) 3 . 1 = 3 mod 20 = 3 3 . 2 = 6 mod 20 = 6 3 . 3 = 9 mod 20 = 9 3 . 4 = 12 mod 20 = 12 3 . 5 = 15 mod 20 = 15 3 . 6 = 18 mod 20 = 18 3 . 7 = 21 mod 20 = 1 3 . 8 = 24 mod 20 = 4 3 . 9 = 27 mod 20 = 7 3.10 = 30 mod 20 = 10 36 woensdag 25 april 12
92. ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = 7 37 woensdag 25 april 12
93. That’s it: ➡ public key = (n, e) = (33, 3) ➡ private key = (n, d) = (33, 7) ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = 7 37 woensdag 25 april 12
94. The actual math is much more complex since we use very large numbers, but it all comes down to these (relatively simple) calculations.. 38 woensdag 25 april 12
95. 39 jthijssen@debian-jth:~$ openssl rsa -text -noout -in server.key woensdag 25 april 12
96. 39 jthijssen@debian-jth:~$ openssl rsa -text -noout -in server.key Private-Key: (256 bit) modulus: 00:c2:d0:c4:1f:6f:78:16:82:d1:0c:dd:5a:af:de:f2:ff:31:c6: 9b:3b:9f:e8:24:2a:5c:06:56:ea:d7:7c:c6:19 publicExponent: 65537 (0x10001) privateExponent: 22:8f:fd:2b:82:90:30:96:36:d6:6c:73:09:5e:a9:87:73:6e: 2d:d4:d5:78:fc:3b:20:ea:0d:02:e5:2b:cb:3d prime1: 00:f0:49:fd:91:18:01:53:92:8f:87:d7:2b:c8:19:7d:17 prime2: 00:cf:8d:a1:3b:93:af:61:77:8f:c9:8f:1d:aa:8d:b4:4f exponent1: 00:e1:d8:c9:89:bc:84:52:a6:a8:5d:47:32:91:6a:d3:95 exponent2: 5a:88:b1:fa:d5:d9:db:8f:16:a6:5a:0a:1b:ba:42:1b coefficient: 00:99:fa:de:80:d4:ee:f3:69:59:e5:8a:72:ad:e5:30:3d woensdag 25 april 12
97. 39 jthijssen@debian-jth:~$ openssl rsa -text -noout -in server.key n e d p q d mod (p-1) e mod (q-1) (inverse q) mod p Private-Key: (256 bit) modulus: 00:c2:d0:c4:1f:6f:78:16:82:d1:0c:dd:5a:af:de:f2:ff:31:c6: 9b:3b:9f:e8:24:2a:5c:06:56:ea:d7:7c:c6:19 publicExponent: 65537 (0x10001) privateExponent: 22:8f:fd:2b:82:90:30:96:36:d6:6c:73:09:5e:a9:87:73:6e: 2d:d4:d5:78:fc:3b:20:ea:0d:02:e5:2b:cb:3d prime1: 00:f0:49:fd:91:18:01:53:92:8f:87:d7:2b:c8:19:7d:17 prime2: 00:cf:8d:a1:3b:93:af:61:77:8f:c9:8f:1d:aa:8d:b4:4f exponent1: 00:e1:d8:c9:89:bc:84:52:a6:a8:5d:47:32:91:6a:d3:95 exponent2: 5a:88:b1:fa:d5:d9:db:8f:16:a6:5a:0a:1b:ba:42:1b coefficient: 00:99:fa:de:80:d4:ee:f3:69:59:e5:8a:72:ad:e5:30:3d woensdag 25 april 12
98. Encrypting a message: c = me mod n Decrypting a message: m = cd mod n 40 woensdag 25 april 12
99. Encrypting a message: private key = (n,d) = (33, 7): Decrypting a message: public key = (n,e) = (33, 3): m = 13, 20, 15, 5 13^7 mod 33 = 7 20^7 mod 33 = 26 15^7 mod 33 = 27 5^7 mod 33 = 14 c = 7, 26, 27,14 41 woensdag 25 april 12
100. Encrypting a message: private key = (n,d) = (33, 7): Decrypting a message: public key = (n,e) = (33, 3): m = 13, 20, 15, 5 13^7 mod 33 = 7 20^7 mod 33 = 26 15^7 mod 33 = 27 5^7 mod 33 = 14 c = 7, 26, 27,14 41 c = 7, 26, 27,14 7^3 mod 33 = 13 26^3 mod 33 = 20 27^3 mod 33 = 15 14^3 mod 33 =5 m = 13, 20, 15, 5 woensdag 25 april 12
101. 42 woensdag 25 april 12
102. ➡ A message is an “integer” 42 woensdag 25 april 12
103. ➡ A message is an “integer” ➡ A message must be between 2 and n-1. 42 woensdag 25 april 12
104. ➡ A message is an “integer” ➡ A message must be between 2 and n-1. ➡ Deterministic, so we must use a padding scheme to make it non-deterministic. 42 woensdag 25 april 12
105. 43 woensdag 25 april 12
106. ➡ Public Key Cryptography Standard #1 43 woensdag 25 april 12
107. ➡ Public Key Cryptography Standard #1 ➡ Pads data with (random) bytes up to n bits in length (v1.5 or OAEP/v2.x). 43 woensdag 25 april 12
108. ➡ Public Key Cryptography Standard #1 ➡ Pads data with (random) bytes up to n bits in length (v1.5 or OAEP/v2.x). ➡ Got it flaws and weaknesses too. Always use the latest available version (v2.1) 43 woensdag 25 april 12
109. Data = 4E636AF98E40F3ADCFCCB698F4E80B9F The encoded message block, EMB, after encoding but before encryption, with random padding bytes shown in green: 0002257F48FD1F1793B7E5E02306F2D3228F5C95ADF5F31566729F132AA12009 E3FC9B2B475CD6944EF191E3F59545E671E474B555799FE3756099F044964038 B16B2148E9A2F9C6F44BB5C52E3C6C8061CF694145FAFDB24402AD1819EACEDF 4A36C6E4D2CD8FC1D62E5A1268F496004E636AF98E40F3ADCFCCB698F4E80B9F After RSA encryption, the output is: 3D2AB25B1EB667A40F504CC4D778EC399A899C8790EDECEF062CD739492C9CE5 8B92B9ECF32AF4AAC7A61EAEC346449891F49A722378E008EFF0B0A8DBC6E621 EDC90CEC64CF34C640F5B36C48EE9322808AF8F4A0212B28715C76F3CB99AC7E 609787ADCE055839829E0142C44B676D218111FFE69F9D41424E177CBA3A435B http://www.di-mgt.com.au/rsa_alg.html#pkcs1schemes 44 woensdag 25 april 12
110. 45 Some words of wisdom: (free of charge) woensdag 25 april 12
111. 46 woensdag 25 april 12
112. ➡ Don’t “invent” your own encryption. It will NOT be secure, and it WILL fail. 46 woensdag 25 april 12
113. ➡ Don’t “invent” your own encryption. It will NOT be secure, and it WILL fail. ➡ Encryption is as strong as the weakest link, which 9 out of 10 times will be you. 46 woensdag 25 april 12
114. ➡ Don’t “invent” your own encryption. It will NOT be secure, and it WILL fail. ➡ Encryption is as strong as the weakest link, which 9 out of 10 times will be you. ➡ Encryptions evolve. Do not use today what you used 10 years ago. 46 woensdag 25 april 12
115. ➡ Don’t “invent” your own encryption. It will NOT be secure, and it WILL fail. ➡ Encryption is as strong as the weakest link, which 9 out of 10 times will be you. ➡ Encryptions evolve. Do not use today what you used 10 years ago. ➡ Every encryption will become obsolete! 46 woensdag 25 april 12
116. ➡ Don’t “invent” your own encryption. It will NOT be secure, and it WILL fail. ➡ Encryption is as strong as the weakest link, which 9 out of 10 times will be you. ➡ Encryptions evolve. Do not use today what you used 10 years ago. ➡ Every encryption will become obsolete! ➡ Always follow the best practices. 46 woensdag 25 april 12
117. http://farm1.static.flickr.com/73/163450213_18478d3aa6_d.jpg Questions? 47 woensdag 25 april 12
118. Thank you 48 Find me on twitter: @jaytaph Find me for development and training: www.noxlogic.nl Find me on email: jthijssen@noxlogic.nl Find me for blogs: www.adayinthelifeof.nl http://xkcd.com/153/ woensdag 25 april 12