Security of Systems and Networks Deel 1 …...– Ceasar Substitutie – Vigenère – Frequency...
Transcript of Security of Systems and Networks Deel 1 …...– Ceasar Substitutie – Vigenère – Frequency...
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SSN
Security of Systems and Networks
Deel 1 Traditionele Crypto29 Oktober 2007
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Evaluatie
● DIA en ESA....
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Dit blok● Maandag en Donderdag
– Security of Systems and Networks SSN– Jaap van Ginkel
● Dinsdag en Woensdag– CIA Classical Internet Applications– Karst Koymans
● Donderdag 16:00 evaluatie● Woensdag
– Colloquia/Uitloop practicum
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Praktica
● Eelco Schatborn● Voortgang in logboek bijhouden !● Werk samen in varierende samenstelling● Eigen inzet is nodig
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Boek
● Basis tentamen
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WIKI
● www.os3.nl
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Machinerie● Dell 850's achter in het rack● Via de 4 consoles● Niet werken in serverruimte !● Multiboot (opzetten bij CIA)● Linux (opzetten bij CIA)● Windows 2003 server (opzetten bij SSN)● Tweede netwerkinterface activeren
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Windows 2003 Server
● Voldoende diskruimte● CD en Key via Jaap/Eelco blijft binnen lab !● Codebook CD● Openoffice (www.openoffice.org)● Wireshark (www.wireshark.com)● Geen DC ● Gebruik DHCP● Naamgeving en adressering !
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Eigen Bijdrage
● “Gevorderden”● Aanmelden bij Jaap● Passend in programma
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Gastdocenten● Karst Koymans Crypto Wiskunde● Rop Gongrijp Stemmachines● Jan Meijer Internetstemmen● Teun Nijssen PKI● Pieter de Boer Bufferoverflows● Leo Willems Social Engineering● Harko Robroch Smartcards● Jeroen van Beek Bluetooth RFID Oracle● Flexibel programma
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HUISREGELS
● Jaap– Je mag werken op je Mac– Je moet aanwezig zijn
● Gastdocenten– Stel (kritische) vragen– Blijf beleefd– Je mag je Mac niet gebruiken– Je moet aanwezig zijn
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Tentamen
● Mogelijk open boek● Save a tree today● Geen electronische hulpmiddelen● Ook gastcollege's en additionele stof
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Beoordeling
● Praktica: Voorwaarde voor cijfer● Project: 30%● Tentamen: 70 %
Mogelijk:● Peer review● Bijdragen
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Film
● Facultatief● Donderdag 16:30 ?● Suggesties
– Enigma– Catch me if you can– A beautiful mind– Sneakers– Breaking the code
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Programma SSN
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Inleiding en Tools
– Protocolanalyse– Werkende machines
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Crypto Historie
– Cryptologie– Ceasar Substitutie– Vigenère – Frequency analyse– Enigma
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Crypto Wiskunde– Number Theory
● Primes● Euler
– Elyptical curves – Rainbow tables– Gastdocent Karst Koymans
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Wachtwoorden– Kraken
● John● Distributed cracking● Rainbow tables● Hashes
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Moderne Crypto– Crypto theorie
● RSA● AES/Rijndael
– Hashes● MD4/MD5/SHA-1● DES/IDEA/AES
– Public key● RSA/Diffie Hellman
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Praktische security
– Firewalls– Wrappers– Port knocking– SSH SCP– LDAP– Windows– Unix– Mac
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Authenticatie
– AuthN/Authz– SSO– Kerberos– A-Select– Shibboleth– Biometrie
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Social Engineering
– De zachte kant– Mogelijk Gastdocent Leo Willems (TUNIX)
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SSL/TLS
– Versies– Ciphers– Implementatie– MITM
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Draadloos● Wireless Security
– 802.11...– WEP– WPA/WPA2– EduRoam
● Bluetooth Security– Tracing
● RFID– Privacy
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Smartcards– Javacard– GSM, RSA– OpenPGPcard– Gastdocent Marc Witteman (Riscure)
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Email security– PGP– S/MIME
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PKI
– Public key crypografie– Trustmodels– Revocation– Keymanagement– TinyCA– Gastdocent Teun Nijsen (UvT Ticer)
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IP-SEC
– IKE/Skip– Praktische implementaties
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Traditionele Crypto
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Cryptology●Cryptography
● Greek kryptós, "hidden", and gráphein, "to write"●Cryptanalysis
● Greek kryptós, "hidden", and analýein, "to loosen" or "to untie")
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Begrippen● Een cipher of cryptosystem wordt gebruikt om de
plaintext versleutelen● Het resultaat is ciphertext ● Een decrypt geeft de plaintext● Een sleutel is de configuratie van de cipher
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In een schema
plaintext
keykey
plaintext
ciphertext
encrypt decrypt
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Cryptography
● Confidentiality● Integrity● Authentication● Non-repudiation● Anti-replay● Proof of delivery
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Cryptography
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Auguste Kerckhoffs● “A cryptosystem
should be secure even if everything about the system, except the key, is public knowledge”
● Claude Shannon "the enemy knows the system"
● No Security by obscurity
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Claude Shannon● Grondlegger Information Theory● Confusion and diffusion
– Confusion obscure relationship between plaintext and ciphertext
– Diffusion spread plaintext statistics through the ciphertext
– Bewees dat one-time secure is.
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Roept u maar
● QNNE FGNNG URYRZNNY AVXF● Vx mvr urg abt avrg
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ROT-13
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Pigpen
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Vrijmetselaars
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Sherlock Holmes● Wie wil er als eerste antwoord geven ?
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Monoalphabetic substitution● Zeg het maar:
OK YOX QA WOQNWXOJK YWX WWQM KBPPOW VDNNWQ RW UDDH WWQ XWKKWHW OFDXODDQMW HOMFHWFFB UDDH VWXDDM YW UBWFWQ VWF NBWQ UWF KBPPOW AOF NW DAFBUDDF
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ROT-13
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ROT-13/CEASAR● Maar 26 mogelijkheden!● Exhaustive key search duur miliseconden● Obfuscation● Hoe beter ?
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Substitutie
● 26 ! meer dan 2^88 mogelijkheden● Exhausitive search duurt millenia● Dus veilig ?
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Al-Kindi
● أبو يوسف يعقوب ابن إسحاق الكندي ● Abū-Yūsuf Ya’qūb ibn Ishāq al-Kindī (c. 801–
873 CE)
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Cryptanalyse● Onmogelijk om alle 288 keys te doorzoeken● Is er een betere methode ?● Frequentie analyse !
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Frequency analysis
● Taalafhankelijk● Langere teksten● Letters ● Paren van letters ● Volgorde van letters
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Cryptanalysis: Terminology
● Een cryptosystem is secure als de enige aanval een “exhaustive search “
● Een cryptosystem is insecure als er een vereenvoudiging bekend is
● Insecure kan soms veiliger zijn dan secure
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Double Transposition● Plaintext: attackxatxdawn
Permute rowsand columns
⇒ Ciphertext: xtawxnattxadakc Key: matrix size and permutations
(3,5,1,4,2) and (1,3,2)
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Codebook● Letterlijk, een boek met “codewords”● Zimmerman Telegram encrypted met codebook
Februar 13605fest 13732finanzielle 13850folgender 13918Frieden 17142Friedenschluss 17149
: :
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ZimmermanTelegram
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ZimmermanTelegramcleartext
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Book crypto● Beale● Drie delen alleen II is ontcijferd● 115, 73, 24, 807, 37, 52, 49, 17, 31, 62, 647, 22, 7, 15, 140, 47, 29, 107, 79, 84, 56, 239, 10, 26,
811, 5, 196, 308, 85, 52, 160, 136, 59, 211, 36, 9, 46, 316, 554, 122, 106, 95, 53, 58, 2, 42, 7, 35, 122, 53, 31, 82, 77, 250, 196, 56, 96, 118, 71, 140, 287, 28, 353, 37, 1005, 65, 147, 807, 24, 3, 8, 12, 47, 43, 59, 807, 45, 316, 101, 41, 78, 154, 1005, 122, 138, 191, 16, 77, 49, 102, 57, 72, 34, 73, 85, 35, 371, 59, 196, 81, 92, 191, 106, 273, 60, 394, 620, 270, 220, 106, 388, 287, 63, 3, 6, 191, 122, 43, 234, 400, 106, 290, 314, 47, 48, 81, 96, 26, 115, 92, 158, 191, 110, 77, 85, 197, 46, 10, 113, 140, 353, 48, 120, 106, 2, 607, 61, 420, 811, 29, 125, 14, 20, 37, 105, 28, 248, 16, 159, 7, 35, 19, 301, 125, 110, 486, 287, 98, 117, 511, 62, 51, 220, 37, 113, 140, 807, 138, 540, 8, 44, 287, 388, 117, 18, 79, 344, 34, 20, 59, 511, 548, 107, 603, 220, 7, 66, 154, 41, 20, 50, 6,
● I have deposited in the county of Bedford about four miles from Bufords in an excavation or vault six feet below the surface of the ground the following articles belonging jointly to the parties whose names are given in number three herewith. The first deposit consisted of ten hundred and fourteen pounds of gold and thirty eight hundred and twelve pounds of silver deposited Nov eighteen nineteen. .....
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Frequentie tabellen
English: ETAONIRSHLDCUPFMWYBGVKQXJZ Dutch: ENIARDTOGLSHVRMUWJBZCPFXYQ Esperanto: AIEONSLTRJUKMPDGCVBFZHQWXY French: EANRSITUOLDCMPVBFGHQJZXY German: ENIRSADTUGHOLBMCWFKVZPJQXY Interlingua: EAILNOSTRUDCMPVGBFHXQJWYZK Italian: EAIOLNRTSCDMPUVGZFBHQ Latin: IEUTAMSNRODLVCPQBFGXHJKWYZ Portuguese: EAOSIDRTNCPUMLVFGQHJXZBKWY Spanish: EAOSRNIDLCTUMPGWBQVHFZ Swedish: AENRTSIOMGKLDVFBCHPUYJXQWZ
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Tabel ?
TUVWXYZKOFIEABCDGHJLMNPQRSHJLMNPQRSTUVWXYZKOFIEABCDGEABCDGHJLMNPQRSTUVWXYZKOFIEABCDGHJLMNPQRSTUVWXYZKOFITUVWXYZKOFIEABCDGHJLMNPQRSHJLMNPQRSTUVWXYZKOFIEABCDGEABCDGHJLMNPQRSTUVWXYZKOFIEABCDGHJLMNPQRSTUVWXYZKOFITUVWXYZKOFIEABCDGHJLMNPQRSHJLMNPQRSTUVWXYZKOFIEABCDGEABCDGHJLMNPQRSTUVWXYZKOFIEABCDGHJLMNPQRSTUVWXYZKOFITUVWXYZKOFIEABCDGHJLMNPQRSHJLMNPQRSTUVWXYZKOFIEABCDG
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Di-Graph tabel
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Polyalphabetical Substitution● Wie het weet mag het zeggen● ICHAQBEZQPJIOYAWFADVNBRNVKNGBHC
SGPNJYFQZJOLWGIBNXSKIVCVSCIBFGCELOBBGAMCBQWIMHBEOEMJFYBNJURMVNVLRKHPZJPUWAOCUSGVCBRDVRMWTVWFPUNXUHIPRKBQIUBDCSZNCOOGARQSRZITRCCZMVVCHNSNFDVBCPUSFRIUYIKBCUQVWXMCUKHPWOSOSAWFNBSYIRGKZVIWPYTSMNNXRAWCNLFVBRFRQBNORO