15. “algorithm”:
c = m + k mod 26
‣ CAESARIAN CIPHER or CAESARIAN SHIFT
http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg
9
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16. “algorithm”:
c = m + k mod 26
Message: C O D E
‣ CAESARIAN CIPHER or CAESARIAN SHIFT
http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg
9
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17. “algorithm”:
c = m + k mod 26
Message: C O D E
Ciphertext (key=1): DPEF
‣ CAESARIAN CIPHER or CAESARIAN SHIFT
http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg
9
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18. “algorithm”:
c = m + k mod 26
Message: C O D E
Ciphertext (key=1): DPEF
Ciphertext (key=2): EQFG
‣ CAESARIAN CIPHER or CAESARIAN SHIFT
http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg
9
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19. “algorithm”:
c = m + k mod 26
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
‣ CAESARIAN CIPHER or CAESARIAN SHIFT
http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg
9
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20. “algorithm”:
c = m + k mod 26
Message: C O D E
Ciphertext (key=1): D P E F Ciphertext (key=0): C O D E
Ciphertext (key=2): E Q F G
Ciphertext (key=-1): B M C D
‣ CAESARIAN CIPHER or CAESARIAN SHIFT
http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg
9
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21. “algorithm”:
c = m + k mod 26
Message: C O D E
Ciphertext (key=1): D P E F Ciphertext (key=0): C O D E
Ciphertext (key=2): E Q F G Ciphertext (key=26): C O D E
Ciphertext (key=-1): B M C D
‣ CAESARIAN CIPHER or CAESARIAN SHIFT
http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg
9
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22. “algorithm”:
c = m + k mod 26
Message: C O D E
Ciphertext (key=1): D P E F Ciphertext (key=0): C O D E
Ciphertext (key=2): E Q F G Ciphertext (key=26): C O D E
Ciphertext (key=-1): B M C D Ciphertext (key=52): C O D E
‣ CAESARIAN CIPHER or CAESARIAN SHIFT
http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Caesar3.svg
9
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23. ‣ FLAWS IN THESE CIPHERS
10
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24. ➡ Key is too easy to guess.
‣ FLAWS IN THESE CIPHERS
10
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25. ➡ Key is too easy to guess.
➡ Key has to be send to Bob.
‣ FLAWS IN THESE CIPHERS
10
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26. ➡ Key is too easy to guess.
➡ Key has to be send to Bob.
➡ Deterministic.
‣ FLAWS IN THESE CIPHERS
10
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27. ➡ Key is too easy to guess.
➡ Key has to be send to Bob.
➡ Deterministic.
➡ Prone to frequency analysis.
‣ FLAWS IN THESE CIPHERS
10
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29. ➡ The usage of every letter in the English (or
any other language) can be represented by
a percentage.
11
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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
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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
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32. 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."
http://www.gutenberg.org/cache/epub/14082/pg14082.txt 12
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33. A small bit of text can result in differences, but still there are
some letters we can deduce..
‣ “THE RAVEN”, FIRST PARAGRAPH 13
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34. We can deduce almost all letters just without even CARING
about the crypto algorithm used.
‣ “THE RAVEN”, ALL PARAGRAPHS 14
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35. ‣ FLAWS IN THESE CIPHERS
15
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36. ➡ Determinism and the ability to use
frequency analysis are “bad things”
‣ FLAWS IN THESE CIPHERS
15
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38. ➡ Previous examples were symmetrical encryptions.
‣ SYMMETRICAL ALGORITHMS 16
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39. ➡ Previous examples were symmetrical encryptions.
➡ Same key is used for both encryption and decryption.
‣ SYMMETRICAL ALGORITHMS 16
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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
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41. ‣ THE PROBLEM WITH SYMMETRICAL ALGORITHMS 17
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42. How does Alice send over the key securely
to Bob? Everybody’s listening!
‣ THE PROBLEM WITH SYMMETRICAL ALGORITHMS 17
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44. Two keys instead of one:
public key - available for everybody.
Can be published on your blog.
private key - For your eyes only!
19
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45. ‣ USES 2 KEYS INSTEAD OF ONE: A KEYPAIR
20
http://upload.wikimedia.org/wikipedia/commons/f/f9/Public_key_encryption.svg
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46. It is NOT possible to decrypt the message
with same key that is used to encrypt.
21
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47. Encrypt with public key:
- only private key (thus Alice) can decrypt.
- message is only for Alice = encryption
22
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48. Encrypt with public key:
- only private key (thus Alice) can decrypt.
- message is only for Alice = encryption
Encrypt with private key:
- only public key can decrypt.
- message is guaranteed coming for Alice = signing
22
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49. Symmetrical Asymmetrical
✓ quick. ✓ no need to send over the
✓ not resource intensive. (whole) key.
✓useful for small and large ✓ can be used for encryption
messages. and validation (signing).
✗ need to send over the key
✗ very resource intensive.
to the other side.
✗ only useful for small messages.
23
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50. Use symmetrical encryption for the (large) message
and encrypt the key used with an asymmetrical
encryption method.
24
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51. Hybrid
✓ quick
✓ not resource intensive
✓ useful for small and large messages
✓ safely exchange key data
25
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52. Hybrid
✓ quick
✓ not resource intensive
✓ useful for small and large messages
✓ safely exchange key data
+
http://www.zastavki.com/pictures/1152x864/2008/Animals_Cats_Small_cat_005241_.jpg 25
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55. RSA
Ron Rivest, Adi Shamir, Leonard Adleman
27
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56. RSA
Ron Rivest, Adi Shamir, Leonard Adleman
1978
27
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57. RSA
Ron Rivest, Adi Shamir, Leonard Adleman
1978
Pierre de Fermat, Leonard Euler
17th - 18th century
27
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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
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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
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62. “large” number: 221
but we cannot calculate its
prime factors without brute force.
There is no “formula” (like e=mc2)
29
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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
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65. ➡ There is no proof that it’s impossible to refactor
quickly (all tough it doesn’t look plausible)
30
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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
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67. The math
behind the curtain
31
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69. ➡ p = (large) prime number
32
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70. ➡ p = (large) prime number
➡ q = (large) prime number (but not too close to p)
32
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71. ➡ p = (large) prime number
➡ q = (large) prime number (but not too close to p)
➡ n = p .q (bit length of the RSA key)
32
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72. ➡ 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)
32
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73. ➡ 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
32
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74. ➡ 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
32
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75. Step 1: select primes P and Q
‣ P = ? | Q = ? | N = ? | Phi = ? | e = ? | d = ? 33
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76. Step 1: select primes P and Q
‣ P = 11
‣ P = ? | Q = ? | N = ? | Phi = ? | e = ? | d = ? 33
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77. Step 1: select primes P and Q
‣ P = 11
‣ Q=3
‣ P = ? | Q = ? | N = ? | Phi = ? | e = ? | d = ? 33
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78. Step 2: calculate N and Phi
‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34
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79. Step 2: calculate N and Phi
➡ N = P . Q = 11 . 3 = 33
‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34
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80. Step 2: calculate N and Phi
➡ N = P . Q = 11 . 3 = 33
➡ φ = (11-1) . (3-1) = 10 . 2 = 20
‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34
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81. Step 2: calculate N and Phi
➡ N = P . Q = 11 . 3 = 33
➡ φ = (11-1) . (3-1) = 10 . 2 = 20
33 decimal is 100001 in binary == 6 bit key
‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34
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82. Step 2: calculate N and Phi
➡ N = P . Q = 11 . 3 = 33
➡ φ = (11-1) . (3-1) = 10 . 2 = 20
33 decimal is 100001 in binary == 6 bit key
There are 20 co primes for 33 : φ(33) = 20
‣ P = 11 | Q = 3 | N = ? | Phi = ? | e = ? | d = ? 34
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83. Step 3: find e
‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = ? | d = ? 35
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84. Step 3: find e
‣ e=3
‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = ? | d = ? 35
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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
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86. Step 3: find e
‣ e=3
‣ gcd(e, φ) = 1 ==> gcd(3, 20) = 1
n
2
Fermat number: 2 + 1
‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = ? | d = ? 35
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87. Step 3: find e
‣ e=3
‣ gcd(e, φ) = 1 ==> gcd(3, 20) = 1
n
2
Fermat number: 2 + 1
Fermat prime: Fermat that is prime: 3, 5, 17, 257, 65537
Study shows that 98.5% of the time 65537 is used
‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = ? | d = ? 35
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88. Step 4: find d
‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = ? 36
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89. Step 4: find d
‣ Extended Euclidean Algorithm gives 7
‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = ? 36
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90. Step 4: find d
‣ Extended Euclidean Algorithm gives 7
‣ brute force: (e.d mod φ = 1)
‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = ? 36
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91. Step 4: find d
‣ Extended Euclidean Algorithm gives 7
‣ brute force: (e.d mod φ = 1)
3 . 1 = 3 mod 20 = 3 3 . 6 = 18 mod 20 = 18
3 . 2 = 6 mod 20 = 6 3 . 7 = 21 mod 20 = 1
3 . 3 = 9 mod 20 = 9 3 . 8 = 24 mod 20 = 4
3 . 4 = 12 mod 20 = 12 3 . 9 = 27 mod 20 = 7
3 . 5 = 15 mod 20 = 15 3.10 = 30 mod 20 = 10
‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = ? 36
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92. ‣ P = 11 | Q = 3 | N = 33 | Phi = 20 | e = 3 | d = 7 37
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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
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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
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97. jthijssen@debian-jth:~$ openssl rsa -text -noout -in server.key
Private-Key: (256 bit)
modulus:
n
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)
e
privateExponent:
22:8f:fd:2b:82:90:30:96:36:d6:6c:73:09:5e:a9:87:73:6e:
d
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 p
prime2:
00:cf:8d:a1:3b:93:af:61:77:8f:c9:8f:1d:aa:8d:b4:4f
exponent1: q
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
d mod (p-1)
coefficient:
00:99:fa:de:80:d4:ee:f3:69:59:e5:8a:72:ad:e5:30:3d
e mod (q-1)
(inverse q) mod p
39
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98. Encrypting a message:
c = me mod n
Decrypting a message:
m = cd mod n
40
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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
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100. Encrypting a message: private key = (n,d) = (33, 7):
Decrypting a message: public key = (n,e) = (33, 3):
m = 13, 20, 15, 5 c = 7, 26, 27,14
13^7 mod 33 = 7 7^3 mod 33 = 13
20^7 mod 33 = 26 26^3 mod 33 = 20
15^7 mod 33 = 27 27^3 mod 33 = 15
5^7 mod 33 = 14 14^3 mod 33 =5
c = 7, 26, 27,14 m = 13, 20, 15, 5
41
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102. ➡ A message is an “integer”
42
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103. ➡ A message is an “integer”
➡ A message must be between 2 and n-1.
42
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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
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106. ➡ Public Key Cryptography Standard #1
43
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107. ➡ Public Key Cryptography Standard #1
➡ Pads data with (random) bytes up to n bits
in length (v1.5 or OAEP/v2.x).
43
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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
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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
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112. HTTPS
➡ HTTP encapsulated by TLS (previously SSL).
46
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113. HTTPS
➡ HTTP encapsulated by TLS (previously SSL).
➡ More or less: an encryption layer on top of http.
46
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114. HTTPS
➡ HTTP encapsulated by TLS (previously SSL).
➡ More or less: an encryption layer on top of http.
➡ Myth: HTTPS uses public key encryption for
communication.
46
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115. HTTPS
➡ HTTP encapsulated by TLS (previously SSL).
➡ More or less: an encryption layer on top of http.
➡ Myth: HTTPS uses public key encryption for
communication.
➡ Fact: HTTPS uses public key encryption to SETUP
communication.
46
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116. jthijssen@debian-jth:~$ openssl x509 -text -noout -in github.pem
Certificate:
Data:
Version: 3 (0x2)
Serial Number:
0e:77:76:8a:5d:07:f0:e5:79:59:ca:2a:9d:50:82:b5
Signature Algorithm: sha1WithRSAEncryption
Issuer: C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert High Assurance EV CA-1
Validity
Not Before: May 27 00:00:00 2011 GMT
Not After : Jul 29 12:00:00 2013 GMT
Subject: businessCategory=Private Organization/1.3.6.1.4.1.311.60.2.1.3=US/
1.3.6.1.4.1.311.60.2.1.2=California/serialNumber=C3268102, C=US, ST=California, L=San Francisco, O=GitHub, Inc.,
CN=github.com
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
RSA Public Key: (2048 bit)
Modulus (2048 bit):
00:ed:d3:89:c3:5d:70:72:09:f3:33:4f:1a:72:74:
d9:b6:5a:95:50:bb:68:61:9f:f7:fb:1f:19:e1:da:
04:31:af:15:7c:1a:7f:f9:73:af:1d:e5:43:2b:56:
09:00:45:69:4a:e8:c4:5b:df:c2:77:52:51:19:5b:
d1:2b:d9:39:65:36:a0:32:19:1c:41:73:fb:32:b2:
3d:9f:98:ec:82:5b:0b:37:64:39:2c:b7:10:83:72:
cd:f0:ea:24:4b:fa:d9:94:2e:c3:85:15:39:a9:3a:
f6:88:da:f4:27:89:a6:95:4f:84:a2:37:4e:7c:25:
78:3a:c9:83:6d:02:17:95:78:7d:47:a8:55:83:ee:
13:c8:19:1a:b3:3c:f1:5f:fe:3b:02:e1:85:fb:11:
66:ab:09:5d:9f:4c:43:f0:c7:24:5e:29:72:28:ce:
d4:75:68:4f:24:72:29:ae:39:28:fc:df:8d:4f:4d:
83:73:74:0c:6f:11:9b:a7:dd:62:de:ff:e2:eb:17:
e6:ff:0c:bf:c0:2d:31:3b:d6:59:a2:f2:dd:87:4a:
48:7b:6d:33:11:14:4d:34:9f:32:38:f6:c8:19:9d:
f1:b6:3d:c5:46:ef:51:0b:8a:c6:33:ed:48:61:c4:
1d:17:1b:bd:7c:b6:67:e9:39:cf:a5:52:80:0a:f4:
ea:cd
Exponent: 65537 (0x10001)
47
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118. HTTPS
➡ Browser sends over its encryption methods.
48
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119. HTTPS
➡ Browser sends over its encryption methods.
➡ Server decides which one to use.
48
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120. HTTPS
➡ Browser sends over its encryption methods.
➡ Server decides which one to use.
➡ Server send certificate(s).
48
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121. HTTPS
➡ Browser sends over its encryption methods.
➡ Server decides which one to use.
➡ Server send certificate(s).
➡ Client sends “session key” encrypted by the
public key found in the server certificate.
48
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122. HTTPS
➡ Browser sends over its encryption methods.
➡ Server decides which one to use.
➡ Server send certificate(s).
➡ Client sends “session key” encrypted by the
public key found in the server certificate.
➡ Server and client uses the “session key” for
symmetrical encryption.
48
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124. HTTPS
➡ Thus: Public/private encryption is only used in
establishing a secondary (better!?) encryption.
49
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125. HTTPS
➡ Thus: Public/private encryption is only used in
establishing a secondary (better!?) encryption.
➡ SSL/TLS is a separate talk (it’s way more complex
as this)
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126. HTTPS
➡ Thus: Public/private encryption is only used in
establishing a secondary (better!?) encryption.
➡ SSL/TLS is a separate talk (it’s way more complex
as this)
➡ http://www.moserware.com/2009/06/first-few-
milliseconds-of-https.html
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130. Questions:
➡ Did Bill really send this email?
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131. Questions:
➡ Did Bill really send this email?
➡ Do we know for sure that nobody has read
this email (before it came to us?)
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132. Questions:
➡ Did Bill really send this email?
➡ Do we know for sure that nobody has read
this email (before it came to us?)
➡ Do we know for sure that the contents of
the message isn’t tampered with?
52
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133. Questions:
➡ Did Bill really send this email?
➡ Do we know for sure that nobody has read
this email (before it came to us?)
➡ Do we know for sure that the contents of
the message isn’t tampered with?
➡ We use signing!
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135. Signing a message
➡ Signing a message means adding a signature
that authenticates the validity of a message.
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136. Signing a message
➡ Signing a message means adding a signature
that authenticates the validity of a message.
➡ Like md5 or sha1, so when the message
changes, so will the signature.
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137. Signing a message
➡ Signing a message means adding a signature
that authenticates the validity of a message.
➡ Like md5 or sha1, so when the message
changes, so will the signature.
➡ This works on the premise that Alice and
only Alice has the private key that can
create the signature.
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138. Signing a message
http://en.wikipedia.org/wiki/File:Digital_Signature_diagram.svg 54
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141. Introduction a pretty-good-privacy
➡ GPG / PGP: Application for signing and/or
encrypting data (or emails).
➡ Try it yourself with Thunderbird’s Enigmail
extension.
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142. Introduction a pretty-good-privacy
➡ GPG / PGP: Application for signing and/or
encrypting data (or emails).
➡ Try it yourself with Thunderbird’s Enigmail
extension.
➡ Public keys can be send / found on PGP-
servers so you don’t need to send your
keys to everybody all the time.
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144. ‣ Everybody can send emails that ONLY YOU can read.
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145. ‣ Everybody can send emails that ONLY YOU can read.
‣ Everybody can verify that YOU have send the email
and that it is authentic.
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146. ‣ Everybody can send emails that ONLY YOU can read.
‣ Everybody can verify that YOU have send the email
and that it is authentic.
‣ Why is this not the standard?
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147. ‣ Everybody can send emails that ONLY YOU can read.
‣ Everybody can verify that YOU have send the email
and that it is authentic.
‣ Why is this not the standard?
‣ No really, why isn’t it the standard?
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150. SSH
➡ Public key authentication
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151. SSH
➡ Public key authentication
➡ Because you suck at creating and/or
remembering passwords
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152. ➡ Run ssh-keygen
➡ copy id_rsa.pub over to server’s ~/.ssh/
authorized_keys
➡ Easy for tools / scripts to connect
➡ Easy for you (no remembering passwords)
➡ More fine grained security model.
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156. ➡ Don’t “invent” your own encryption. It will
NOT be secure, and it WILL fail.
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157. ➡ 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.
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158. ➡ 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.
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159. ➡ 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!
62
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160. ➡ 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.
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162. Thank you
Find me on twitter: @jaytaph
Find me on email: jthijssen@noxlogic.nl
Find me for blogs: www.adayinthelifeof.nl
Find me for development and training: www.noxlogic.nl
http://xkcd.com/153/ 64
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