Dasar-Dasar Keamanan Sistem Informasi

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Dasar-Dasar Keamanan Sistem Informasi

  1. 1. #3 Keamanan Sistem Informasi Berbasis Internet Dasar-Dasar Keamanan Sistem Informasi Wildan Maulana wildan.m@openthinklabs.com http://computersecurity.openthinklabs.com/
  2. 2. Selayang Pandang● Terminologi ● Public-key● Enkripsi cryptography lawan ● Elemen dari Enkripsi symmetric ● Substitution Cipher cryptography dengan Caesar Cipher ● Data Encryption ● ROT13 Standard (DES) ● Multiple-letter Encryption ● Memecahkan DES ● Enigma Rotor Machine ● Bahan Bacaan DES ● Penggunaan Kunci ● Aplikasi dari Enkripsi ● Hash function – integrity checking
  3. 3. TerminologiKriptografi (cryptography) merupakan ilmu dan seni untuk menjaga pesan agar aman
  4. 4. EnkripsiE(M) = C D(C) = M Img:src=http://en.wikipedia.org/wiki/Cryptography
  5. 5. Elemen dari Enkripsi● Algoritma dari Enkripsi dan Dekripsi● Kunci yang digunakan dan panjangnya kunci● Plaintext● Ciphertext
  6. 6. Substitution Cipherdengan Caesar Cipher Img:src=http://en.wikipedia.org/wiki/Caesar_cipher
  7. 7. ROT13 Img:src=http://en.wikipedia.org/wiki/ROT13
  8. 8. Multiple-letter encryption Ex : Playfair cipher
  9. 9. Playfair ExampleThe Key : The Message : Hide the gold in the tree stump. HI DE TH EG OL DI NT HE TR EX ES TU MP
  10. 10. The pair HI forms a rectangle, replace it with BM
  11. 11. The pair DE is in a column, replace it with OD
  12. 12. The pair TH forms a rectangle, replace it with ZB
  13. 13. The pair EG forms a rectangle, replace it with XD
  14. 14. The pair OL forms a rectangle, replace it with NA
  15. 15. Playfair Example The Result Hide the gold in the tree stumpBMODZBXDNABEKUDMUIXMMOUVIF
  16. 16. Enigma Rotor Machine Img:src=http://en.wikipedia.org/wiki/Enigma_rotor_details
  17. 17. Penggunaan Kunci● Keyspace (K) : Rentang dari kemungkinan angka (harga) dari kunci K EK(M) = C DK(M) = M
  18. 18. Aplikasi dari Enkripsi● Pretty Good Privacy (PGP)● Secure Shell (SSH)
  19. 19. Public-key cryptography lawan symmetric cryptography
  20. 20. Data Encryption Standard (DES) The Feistel function (F function) of DES
  21. 21. Memecahkan DES● http://www.distributed.net/● EFF DES cracker
  22. 22. Hash function - integrity checking● MD5● SHA
  23. 23. Q&Ahttp://computersecurity.openthinklabs.com/
  24. 24. Reference● Budi Rahardjo: Keamanan Sistem Informasi Berbasis Internet, 1999

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