Information security - Paylogic TechTalk 2014

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A primer in information security, giving an intro to the foundations, examples of different kinds vulnerabilities, and a bunch of extra info.

A primer in information security, giving an intro to the foundations, examples of different kinds vulnerabilities, and a bunch of extra info.

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  • 1. Informa(on Security Tech Talk Aug 4th 2014 Dirk Zi=ersteyn
  • 2. Informa(on security Three main goals
  • 3. Keep your data secure
  • 4. Make sure people can’t change your data
  • 5. Make sure your informa(on stays available
  • 6. Confiden(ality Integrity Availability
  • 7. Confiden(ality Integrity Availability
  • 8. Availability Subject for another talk
  • 9. Confiden(ality and Integrity Two sides of the same coin If you can’t guarantee integrity, confiden(ality is useless, and vice-­‐versa.
  • 10. Cryptography Confiden(ality Integrity (a bit)
  • 11. Basic Terminology: Plaintext Encryp(on Key Ciphertext Decryp(on Key Plaintext
  • 12. Basic Terminology: Plaintext Encryp(on Key Ciphertext Decryp(on Key Plaintext = Symmetric encryp(on
  • 13. Basic Terminology: Plaintext Encryp(on Key Ciphertext Decryp(on Key Plaintext ≠ Asymmetric encryp(on
  • 14. Founda(ons Kerckhoffs (1835 – 1903) Shannon (1916 – 2001)
  • 15. Auguste Kerckhoffs La Cryptographie Militaire (1883)
  • 16. Kerckhoffs’ principle The design of a system should not require secrecy
  • 17. Kerckhoffs’ principle The design of a system should not require secrecy and compromise of the system should not inconvenience the correspondents
  • 18. Kerckhoffs’ principle Open Source your method
  • 19. Kerckhoffs’ principle Security is in the key
  • 20. Claude Shannon Perfect Secrecy Confusion Diffusion
  • 21. Claude Shannon "Perfect Secrecy" is defined by requiring of a system that after a cryptogram is intercepted by the enemy, the a posteriori probabilities of this cryptogram representing various messages be identically the same as the a priori probabilities of the same messages before the interception
  • 22. In other words: The enemy learns nothing.
  • 23. Claude Shannon Confusion: Rela(on plaintext -­‐ ciphertext
  • 24. Claude Shannon Diffusion: Posi(on of plaintext in ciphertext
  • 25. Back in the days… Caesar Cipher
  • 26. caesar = alpha[n:] + alpha[:n]
  • 27. caesar(‘Hello World’, 3) = ‘KHOOR ZRUOG’
  • 28. Decrypt Simple.
  • 29. Decrypt A li=le… too simple.
  • 30. for i in range(26): print caesar('KHOOR ZRUOG', i)
  • 31. 0: KHOOR ZRUOG 1: LIPPS ASVPH 2: MJQQT BTWQI 3: NKRRU CUXRJ 4: OLSSV DVYSK 5: PMTTW EWZTL 6: QNUUX FXAUM 7: ROVVY GYBVN 8: SPWWZ HZCWO 9: TQXXA IADXP 10: URYYB JBEYQ 11: VSZZC KCFZR 12: WTAAD LDGAS 13: XUBBE MEHBT 14: YVCCF NFICU 15: ZWDDG OGJDV 16: AXEEH PHKEW 17: BYFFI QILFX 18: CZGGJ RJMGY 19: DAHHK SKNHZ 20: EBIIL TLOIA 21: FCJJM UMPJB 22: GDKKN VNQKC 23: HELLO WORLD 24: IFMMP XPSME 25: JGNNQ YQTNF
  • 32. ecuritysay oughthray obscurityyay
  • 33. ecuritysay oughthray obscurityyay They simply assumed no-­‐one would think t o decrypt it (they even hardcoded the number by which is was shi`ed: 3)
  • 34. KHOOR Z'RUOG! (Klingons never bluff) They hoped people would think it was some language they did not understand
  • 35. Kerckhoffs’ principle
  • 36. Improving Caesar shi` Keyspace ≈ 26
  • 37. Generalizing Caesar shi` ABCDEFGHIJKLMNOPQRSTUVWXYZ alpha = alpha[n:] + alpha[:n] DEFGHIJKLMNOPQRSTUVWXYZABC
  • 38. Subs(tu(on cipher ABCDEFGHIJKLMNOPQRSTUVWXYZ alpha = random.shuffle(alpha) WGLOJTYUDZQXKVAFHMBPECRNIS
  • 39. Subs(tu(on cipher Keyspace ≈ 26! 403291461126605635584000000
  • 40. Secure?
  • 41. You intercept: MHT UTEKAVAMRPD PS RDUTJTDUTDET RZ MHT WZWAK DABT PS A ZMAMTBTDM AUPJMTU OG MHT EPDMRDTDMAK EPDNVTZZ PD CWKG 4, 1776, LHREH ADDPWDETU MHAM MHT MHRVMTTD ABTVREAD EPKPDRTZ, MHTD AM LAV LRMH NVTAM OVRMARD, VTNAVUTU MHTBZTKQTZ AZ MHRVMTTD DTLKG RDUTJTDUTDM ZPQTVTRND ZMAMTZ, ADU DP KPDNTV A JAVM PS MHT OVRMRZH TBJRVT. RDZMTAU MHTG SPVBTU A DTL DAMRPD - MHT WDRMTU ZMAMTZ PS ABTVREA. CPHD AUABZ LAZ A KTAUTV RD JWZHRDN SPV RDUTJTDUTDET, LHREH LAZ WDADRBPWZKG AJJVPQTU PD CWKG 2. A EPBBRMMTT PS SRQT HAU AKVTAUG UVASMTU MHT SPVBAK UTEKAVAMRPD, MP OT VTAUG LHTD EPDNVTZZ QPMTU PD RDUTJTDUTDET. MHT MTVB "UTEKAVAMRPD PS RDUTJTDUTDET" RZ DPM WZTU RD MHT UPEWBTDM RMZTKS. …
  • 42. English le=er freq’s
  • 43. Message le=er freq’s
  • 44. Pre=y similar! English Message
  • 45. a d
  • 46. ab do
  • 47. abc dok
  • 48. abcdefghijklmnopqrstuvwxyz dokutbnvrxcespalyhzmwqjfgi
  • 49. Guessed key dokutbnvrxcespalyhzmwqjfgi
  • 50. Guessed key dokutbnvrxcespalyhzmwqjfgi aoeutsnhrcxkbdpjyvzmwqlfgi Actual key
  • 51. Similar enough to come close Guessed key dokutbnvrxcespalyhzmwqjfgi aoeutsnhrcxkbdpjyvzmwqlfgi Actual key
  • 52. More work needed Guessed key dokutbnvrxcespalyhzmwqjfgi aoeutsnhrcxkbdpjyvzmwqlfgi Actual key
  • 53. There are some pre=y big mismatches
  • 54. Decoded with guessed key TRE DELCOHOTINA NM IADEWEADEALE IS TRE USUOC AOFE NM O STOTEFEAT ODNWTED BY TRE LNATIAEATOC LNAGHESS NA KUCY 4, 1776, PRILR OAANUALED TROT TRE TRIHTEEA OFEHILOA LNCNAIES, TREA OT POH PITR GHEOT BHITOIA, HEGOHDED TREFSECVES OS TRIHTEEA AEPCY IADEWEADEAT SNVEHEIGA STOTES, OAD AN CNAGEH O WOHT NM TRE BHITISR EFWIHE. IASTEOD TREY MNHFED O AEP AOTINA - TRE UAITED STOTES NM OFEHILO. KNRA ODOFS POS O CEODEH IA WUSRIAG MNH IADEWEADEALE, PRILR POS UAOAIFNUSCY OWWHNVED NA KUCY 2. O LNFFITTEE NM MIVE ROD OCHEODY DHOMTED TRE MNHFOC DELCOHOTINA, TN BE HEODY PREA LNAGHESS VNTED NA IADEWEADEALE. TRE TEHF "DELCOHOTINA NM IADEWEADEALE" IS ANT USED IA TRE DNLUFEAT ITSECM.
  • 55. We’ve assumed it’s English TRE DELCOHOTINA NM IADEWEADEALE IS TRE USUOC AOFE NM O STOTEFEAT ODNWTED BY TRE LNATIAEATOC LNAGHESS NA KUCY 4, 1776, PRILR OAANUALED TROT TRE TRIHTEEA OFEHILOA LNCNAIES, TREA OT POH PITR GHEOT BHITOIA, HEGOHDED TREFSECVES OS TRIHTEEA AEPCY IADEWEADEAT SNVEHEIGA STOTES, OAD AN CNAGEH O WOHT NM TRE BHITISR EFWIHE. IASTEOD TREY MNHFED O AEP AOTINA - TRE UAITED STOTES NM OFEHILO. KNRA ODOFS POS O CEODEH IA WUSRIAG MNH IADEWEADEALE, PRILR POS UAOAIFNUSCY OWWHNVED NA KUCY 2. O LNFFITTEE NM MIVE ROD OCHEODY DHOMTED TRE MNHFOC DELCOHOTINA, TN BE HEODY PREA LNAGHESS VNTED NA IADEWEADEALE. TRE TEHF "DELCOHOTINA NM IADEWEADEALE" IS ANT USED IA TRE DNLUFEAT ITSECM. So let’s find some English words
  • 56. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z TRE DELCOHOTINA NM IADEWEADEALE IS TRE USUOC AOFE NM O STOTEFEAT ODNWTED BY TRE LNATIAEATOC LNAGHESS NA KUCY 4, 1776, PRILR OAANUALED TROT TRE TRIHTEEA OFEHILOA LNCNAIES, TREA OT POH PITR GHEOT BHITOIA, HEGOHDED TREFSECVES OS TRIHTEEA AEPCY IADEWEADEAT SNVEHEIGA STOTES, OAD AN CNAGEH O WOHT NM TRE BHITISR EFWIHE. IASTEOD TREY MNHFED O AEP AOTINA - TRE UAITED STOTES NM OFEHILO. KNRA ODOFS POS O CEODEH IA WUSRIAG MNH IADEWEADEALE, PRILR POS UAOAIFNUSCY OWWHNVED NA KUCY 2. O LNFFITTEE NM MIVE ROD OCHEODY DHOMTED TRE MNHFOC DELCOHOTINA, TN BE HEODY PREA LNAGHESS VNTED NA IADEWEADEALE. TRE TEHF "DELCOHOTINA NM IADEWEADEALE" IS ANT USED IA TRE DNLUFEAT ITSECM.
  • 57. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the DeLCOHOtINA NM IADeWeADeALe IS the USUOC AOFe NM O StOteFeAt ODNWteD BY the LNAtIAeAtOC LNAGHeSS NA KUCY 4, 1776, PhILh OAANUALeD thOt the thIHteeA OFeHILOA LNCNAIeS, theA Ot POH PIth GHeOt BHItOIA, HeGOHDeD theFSeCVeS OS thIHteeA AePCY IADeWeADeAt SNVeHeIGA StOteS, OAD AN CNAGeH O WOHt NM the BHItISh eFWIHe. IASteOD theY MNHFeD O AeP AOtINA - the UAIteD StOteS NM OFeHILO. KNhA ODOFS POS O CeODeH IA WUShIAG MNH IADeWeADeALe, PhILh POS UAOAIFNUSCY OWWHNVeD NA KUCY 2. O LNFFIttee NM MIVe hOD OCHeODY DHOMteD the MNHFOC DeLCOHOtINA, tN Be HeODY PheA LNAGHeSS VNteD NA IADeWeADeALe. the teHF "DeLCOHOtINA NM IADeWeADeALe" IS ANt USeD IA the DNLUFeAt ItSeCM.
  • 58. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the DeLCOHOtINA NM IADeWeADeALe IS the USUOC AOFe NM O StOteFeAt ODNWteD BY the LNAtIAeAtOC LNAGHeSS NA KUCY 4, 1776, PhILh OAANUALeD thOt the thIHteeA OFeHILOA LNCNAIeS, theA Ot POH PIth GHeOt BHItOIA, HeGOHDeD theFSeCVeS OS thIHteeA AePCY IADeWeADeAt SNVeHeIGA StOteS, OAD AN CNAGeH O WOHt NM the BHItISh eFWIHe. IASteOD theY MNHFeD O AeP AOtINA - the UAIteD StOteS NM OFeHILO. KNhA ODOFS POS O CeODeH IA WUShIAG MNH IADeWeADeALe, PhILh POS UAOAIFNUSCY OWWHNVeD NA KUCY 2. O LNFFIttee NM MIVe hOD OCHeODY DHOMteD the MNHFOC DeLCOHOtINA, tN Be HeODY PheA LNAGHeSS VNteD NA IADeWeADeALe. the teHF "DeLCOHOtINA NM IADeWeADeALe" IS ANt USeD IA the DNLUFeAt ItSeCM.
  • 59. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the DeLCOrOtiNA NM iADeWeADeALe is the UsUOC AOFe NM O stOteFeAt ODNWteD bY the LNAtiAeAtOC LNAGress NA KUCY 4, 1776, PhiLh OAANUALeD thOt the thirteeA OFeriLOA LNCNAies, theA Ot POr Pith GreOt britOiA, reGOrDeD theFseCVes Os thirteeA AePCY iADeWeADeAt sNVereiGA stOtes, OAD AN CNAGer O WOrt NM the british eFWire. iAsteOD theY MNrFeD O AeP AOtiNA - the UAiteD stOtes NM OFeriLO. KNhA ODOFs POs O CeODer iA WUshiAG MNr iADeWeADeALe, PhiLh POs UAOAiFNUsCY OWWrNVeD NA KUCY 2. O LNFFittee NM MiVe hOD OCreODY DrOMteD the MNrFOC DeLCOrOtiNA, tN be reODY PheA LNAGress VNteD NA iADeWeADeALe. the terF "DeLCOrOtiNA NM iADeWeADeALe" is ANt UseD iA the DNLUFeAt itseCM.
  • 60. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the DeLCOrOtiNA NM iADeWeADeALe is the UsUOC AOFe NM O stOteFeAt ODNWteD bY the LNAtiAeAtOC LNAGress NA KUCY 4, 1776, PhiLh OAANUALeD thOt the thirteeA OFeriLOA LNCNAies, theA Ot POr Pith GreOt britOiA, reGOrDeD theFseCVes Os thirteeA AePCY iADeWeADeAt sNVereiGA stOtes, OAD AN CNAGer O WOrt NM the british eFWire. iAsteOD theY MNrFeD O AeP AOtiNA - the UAiteD stOtes NM OFeriLO. KNhA ODOFs POs O CeODer iA WUshiAG MNr iADeWeADeALe, PhiLh POs UAOAiFNUsCY OWWrNVeD NA KUCY 2. O LNFFittee NM MiVe hOD OCreODY DrOMteD the MNrFOC DeLCOrOtiNA, tN be reODY PheA LNAGress VNteD NA iADeWeADeALe. the terF "DeLCOrOtiNA NM iADeWeADeALe" is ANt UseD iA the DNLUFeAt itseCM.
  • 61. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the DeLCaratiNn NM inDeWenDenLe is the UsUaC naFe NM a stateFent aDNWteD bY the LNntinentaC LNngress Nn KUCY 4, 1776, PhiLh annNUnLeD that the thirteen aFeriLan LNCNnies, then at Par Pith great britain, regarDeD theFseCVes as thirteen nePCY inDeWenDent sNVereign states, anD nN CNnger a Wart NM the british eFWire. insteaD theY MNrFeD a neP natiNn - the UniteD states NM aFeriLa. KNhn aDaFs Pas a CeaDer in WUshing MNr inDeWenDenLe, PhiLh Pas UnaniFNUsCY aWWrNVeD Nn KUCY 2. a LNFFittee NM MiVe haD aCreaDY DraMteD the MNrFaC DeLCaratiNn, tN be reaDY Phen LNngress VNteD Nn inDeWenDenLe. the terF "DeLCaratiNn NM inDeWenDenLe" is nNt UseD in the DNLUFent itseCM.
  • 62. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the DeLCaratiNn NM inDeWenDenLe is the UsUaC naFe NM a stateFent aDNWteD bY the LNntinentaC LNngress Nn KUCY 4, 1776, PhiLh annNUnLeD that the thirteen aFeriLan LNCNnies, then at Par Pith great britain, regarDeD theFseCVes as thirteen nePCY inDeWenDent sNVereign states, anD nN CNnger a Wart NM the british eFWire. insteaD theY MNrFeD a neP natiNn - the UniteD states NM aFeriLa. KNhn aDaFs Pas a CeaDer in WUshing MNr inDeWenDenLe, PhiLh Pas UnaniFNUsCY aWWrNVeD Nn KUCY 2. a LNFFittee NM MiVe haD aCreaDY DraMteD the MNrFaC DeLCaratiNn, tN be reaDY Phen LNngress VNteD Nn inDeWenDenLe. the terF "DeLCaratiNn NM inDeWenDenLe" is nNt UseD in the DNLUFent itseCM.
  • 63. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the DeLCaratiNn NM inDeWenDenLe is the UsUaC naFe NM a stateFent aDNWteD bY the LNntinentaC LNngress Nn KUCY 4, 1776, whiLh annNUnLeD that the thirteen aFeriLan LNCNnies, then at war with great britain, regarDeD theFseCVes as thirteen newCY inDeWenDent sNVereign states, anD nN CNnger a Wart NM the british eFWire. insteaD theY MNrFeD a new natiNn - the UniteD states NM aFeriLa. KNhn aDaFs was a CeaDer in WUshing MNr inDeWenDenLe, whiLh was UnaniFNUsCY aWWrNVeD Nn KUCY 2. a LNFFittee NM MiVe haD aCreaDY DraMteD the MNrFaC DeLCaratiNn, tN be reaDY when LNngress VNteD Nn inDeWenDenLe. the terF "DeLCaratiNn NM inDeWenDenLe" is nNt UseD in the DNLUFent itseCM.
  • 64. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the DeLCaratiNn NM inDeWenDenLe is the UsUaC naFe NM a stateFent aDNWteD bY the LNntinentaC LNngress Nn KUCY 4, 1776, whiLh annNUnLeD that the thirteen aFeriLan LNCNnies, then at war with great britain, regarDeD theFseCVes as thirteen newCY inDeWenDent sNVereign states, anD nN CNnger a Wart NM the british eFWire. insteaD theY MNrFeD a new natiNn - the UniteD states NM aFeriLa. KNhn aDaFs was a CeaDer in WUshing MNr inDeWenDenLe, whiLh was UnaniFNUsCY aWWrNVeD Nn KUCY 2. a LNFFittee NM MiVe haD aCreaDY DraMteD the MNrFaC DeLCaratiNn, tN be reaDY when LNngress VNteD Nn inDeWenDenLe. the terF "DeLCaratiNn NM inDeWenDenLe" is nNt UseD in the DNLUFent itseCM.
  • 65. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the deLCaratiNn NM indeWendenLe is the usuaC naFe NM a stateFent adNWted bY the LNntinentaC LNngress Nn KuCY 4, 1776, whiLh annNunLed that the thirteen aFeriLan LNCNnies, then at war with great britain, regarded theFseCVes as thirteen newCY indeWendent sNVereign states, and nN CNnger a Wart NM the british eFWire. instead theY MNrFed a new natiNn - the united states NM aFeriLa. KNhn adaFs was a Ceader in Wushing MNr indeWendenLe, whiLh was unaniFNusCY aWWrNVed Nn KuCY 2. a LNFFittee NM MiVe had aCreadY draMted the MNrFaC deLCaratiNn, tN be readY when LNngress VNted Nn indeWendenLe. the terF "deLCaratiNn NM indeWendenLe" is nNt used in the dNLuFent itseCM.
  • 66. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the deLCaratiNn NM indeWendenLe is the usuaC naFe NM a stateFent adNWted bY the LNntinentaC LNngress Nn KuCY 4, 1776, whiLh annNunLed that the thirteen aFeriLan LNCNnies, then at war with great britain, regarded theFseCVes as thirteen newCY indeWendent sNVereign states, and nN CNnger a Wart NM the british eFWire. instead theY MNrFed a new natiNn - the united states NM aFeriLa. KNhn adaFs was a Ceader in Wushing MNr indeWendenLe, whiLh was unaniFNusCY aWWrNVed Nn KuCY 2. a LNFFittee NM MiVe had aCreadY draMted the MNrFaC deLCaratiNn, tN be readY when LNngress VNted Nn indeWendenLe. the terF "deLCaratiNn NM indeWendenLe" is nNt used in the dNLuFent itseCM.
  • 67. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the deLCaratiNn NM indeWendenLe is the usuaC naFe NM a stateFent adNWted by the LNntinentaC LNngress Nn KuCy 4, 1776, whiLh annNunLed that the thirteen aFeriLan LNCNnies, then at war with great britain, regarded theFseCVes as thirteen newCy indeWendent sNVereign states, and nN CNnger a Wart NM the british eFWire. instead they MNrFed a new natiNn - the united states NM aFeriLa. KNhn adaFs was a Ceader in Wushing MNr indeWendenLe, whiLh was unaniFNusCy aWWrNVed Nn KuCy 2. a LNFFittee NM MiVe had aCready draMted the MNrFaC deLCaratiNn, tN be ready when LNngress VNted Nn indeWendenLe. the terF "deLCaratiNn NM indeWendenLe" is nNt used in the dNLuFent itseCM.
  • 68. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the deLCaratiNn NM indeWendenLe is the usuaC naFe NM a stateFent adNWted by the LNntinentaC LNngress Nn KuCy 4, 1776, whiLh annNunLed that the thirteen aFeriLan LNCNnies, then at war with great britain, regarded theFseCVes as thirteen newCy indeWendent sNVereign states, and nN CNnger a Wart NM the british eFWire. instead they MNrFed a new natiNn - the united states NM aFeriLa. KNhn adaFs was a Ceader in Wushing MNr indeWendenLe, whiLh was unaniFNusCy aWWrNVed Nn KuCy 2. a LNFFittee NM MiVe had aCready draMted the MNrFaC deLCaratiNn, tN be ready when LNngress VNted Nn indeWendenLe. the terF "deLCaratiNn NM indeWendenLe" is nNt used in the dNLuFent itseCM.
  • 69. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the declaration oM indeWendence is the usual naFe oM a stateFent adoWted by the continental congress on Kuly 4, 1776, which announced that the thirteen aFerican colonies, then at war with great britain, regarded theFselVes as thirteen newly indeWendent soVereign states, and no longer a Wart oM the british eFWire. instead they MorFed a new nation - the united states oM aFerica. Kohn adaFs was a leader in Wushing Mor indeWendence, which was unaniFously aWWroVed on Kuly 2. a coFFittee oM MiVe had already draMted the MorFal declaration, to be ready when congress Voted on indeWendence. the terF "declaration oM indeWendence" is not used in the docuFent itselM.
  • 70. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the declaration of indeWendence is the usual naFe of a stateFent adoWted by the continental congress on Kuly 4, 1776, which announced that the thirteen aFerican colonies, then at war with great britain, regarded theFselVes as thirteen newly indeWendent soVereign states, and no longer a Wart of the british eFWire. instead they forFed a new nation - the united states of aFerica. Kohn adaFs was a leader in Wushing for indeWendence, which was unaniFously aWWroVed on Kuly 2. a coFFittee of fiVe had already drafted the forFal declaration, to be ready when congress Voted on indeWendence. the terF "declaration of indeWendence" is not used in the docuFent itself.
  • 71. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the declaration of independence is the usual naFe of a stateFent adopted by the continental congress on Kuly 4, 1776, which announced that the thirteen aFerican colonies, then at war with great britain, regarded theFselVes as thirteen newly independent soVereign states, and no longer a part of the british eFpire. instead they forFed a new nation - the united states of aFerica. Kohn adaFs was a leader in pushing for independence, which was unaniFously approVed on Kuly 2. a coFFittee of fiVe had already drafted the forFal declaration, to be ready when congress Voted on independence. the terF "declaration of independence" is not used in the docuFent itself.
  • 72. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the declaration of independence is the usual name of a statement adopted by the continental congress on Kuly 4, 1776, which announced that the thirteen american colonies, then at war with great britain, regarded themselVes as thirteen newly independent soVereign states, and no longer a part of the british empire. instead they formed a new nation - the united states of america. Kohn adams was a leader in pushing for independence, which was unanimously approVed on Kuly 2. a committee of fiVe had already drafted the formal declaration, to be ready when congress Voted on independence. the term "declaration of independence" is not used in the document itself.
  • 73. E T A O I N S H R D L C U M W F G Y P B V K J X Q Z the declaration of independence is the usual name of a statement adopted by the continental congress on july 4, 1776, which announced that the thirteen american colonies, then at war with great britain, regarded themselves as thirteen newly independent sovereign states, and no longer a part of the british empire. instead they formed a new nation - the united states of america. john adams was a leader in pushing for independence, which was unanimously approved on july 2. a committee of five had already drafted the formal declaration, to be ready when congress voted on independence. the term "declaration of independence" is not used in the document itself.
  • 74. Cracked! So, let’s adap(ng it in a different way
  • 75. Change the shi` each le=er
  • 76. Plaintext: supersecretmessageyoushouldnotsee Key: donotlook
  • 77. Repeat the key supersecretmessageyoushouldnotsee donotlookdonotlookdonotlookdonotl
  • 78. Add plaintext and key supersecretmessageyoushouldnotsee donotlookdonotlookdonotlookdonotl --------------------------------- vicskdsqbhhzsldouobchgaziznqcggxp +
  • 79. This is the Vigenère Cipher Named for Blaise de Vigenère (1523 – 1596)
  • 80. This is the Vigenère Cipher Actually invented by Giovan Bapsta Bellaso (1505 – ??)
  • 81. Also known as: Le Chiffre Indéchiffrable (The Unbreakable Cipher)
  • 82. Secure?
  • 83. Brute Force: possibili(es (n = 9 -­‐> 10795636100592)
  • 84. Frequency analysis? Ciphertext English
  • 85. First: Guess the key length
  • 86. Repeated words, repeated key Key: ABCDABCDABCDABCDABCDABCDABCD Plaintext: CRYPTOISSHORTFORCRYPTOGRAPHY Ciphertext: CSASTPKVSIQUTGQUCSASTPIUAQJB
  • 87. Repeated words, repeated key VHVSSPQUCEMRVBVBBBVHVSURQGIBDUGRNICJQUCERVUAXSSR
  • 88. Repeated words, repeated key VHVSSPQUCEMRVBVBBBVHVSURQGIBDUGRNICJQUCERVUAXSSR VHVS -> VHVS = 18 -> [18, 9, 6, 3, 2, 1]
  • 89. Repeated words, repeated key VHVSSPQUCEMRVBVBBBVHVSURQGIBDUGRNICJQUCERVUAXSSR VHVS -> VHVS = 18 -> [18, 9, 6, 3, 2, 1] QUCE -> QUCE = 30 -> [30, 15, 10, 6, 5, 3, 2, 1]
  • 90. Repeated words, repeated key [18, 9, 6, 3, 2, 1] ∩ [30, 15, 10, 6, 5, 3, 2, 1] = [6, 3, 2, 1]
  • 91. Repeated words, repeated key [18, 9, 6, 3, 2, 1] ∩ [30, 15, 10, 6, 5, 3, 2, 1] = [6, 3, 2, 1]
  • 92. When you assume You make an ass out of u and me
  • 93. When you assume There might not be any repeated words at the right spots
  • 94. If the key length = 2 uhdwpjwndingbhiwjctmljldapdbfakvhxmcakjuwyvrfahuwnhvlbxle ABABABABABABABABABABABABABABABABABABABABABABABABABABABABA
  • 95. If the key length = 2 uhdwpjwndingbhiwjctmljldapdbfakvhxmcakjuwyvrfahuwnhvlbxle ABABABABABABABABABABABABABABABABABABABABABABABABABABABABA udpwdnbijtlladfkhmajwvfhwhlxe hwjnighwcmjdpbavxckuyraunvbl AAAAAAAAAAAAAAAAAAAAAAAAAAAAA BBBBBBBBBBBBBBBBBBBBBBBBBBBB
  • 96. If the key length = 2 uhdwpjwndingbhiwjctmljldapdbfakvhxmcakjuwyvrfahuwnhvlbxle ABABABABABABABABABABABABABABABABABABABABABABABABABABABABA udpwdnbijtlladfkhmajwvfhwhlxe hwjnighwcmjdpbavxckuyraunvbl AAAAAAAAAAAAAAAAAAAAAAAAAAAAA BBBBBBBBBBBBBBBBBBBBBBBBBBBB Should be a standard letter distribution
  • 97. If the key length = 3 uhdwpjwndingbhiwjctmljldapdbfakvhxmcakjuwyvrfahuwnhvlbxle ABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABC uwwibwtjabkxauvawvx hpnnhjmlpfvmkwrhnll djdgiclddahcjyfuhbe AAAAAAAAAAAAAAAAAAA BBBBBBBBBBBBBBBBBBB CCCCCCCCCCCCCCCCCCC Should be a standard letter distribution
  • 98. Let’s try this! Encoded a plaintext with key ‘SECRET’
  • 99. Split the ciphertext,
  • 100. Split the ciphertext, Sort characters by frequency
  • 101. Split the ciphertext, Sort characters by frequency Sum highest frequencies, second highest, etc.
  • 102. secret
  • 103. secret s e c r e t
  • 104. Now that we know the key length, This is not that different from subs(tu(on cipher
  • 105. Cracked! Principle is easy Doing it by hand is tedious
  • 106. Cracked! smurfoncrack.com/pygenere/ source: smurfoncrack.com/pygenere/pygenere.py
  • 107. Is there any truly secure method?
  • 108. Yes.
  • 109. The One-­‐Time pad Looks like Vigenère.
  • 110. The One-­‐Time pad Create a long key, without repeFFon
  • 111. The One-­‐Time pad Create a long key, without repeFFon Securely share it between both par(es
  • 112. The One-­‐Time pad To send a message:
  • 113. Plaintext attackatdawn Key owbxelcixrql ------------ + Ciphertext opuxgvcbarmy
  • 114. And then:
  • 115. And then: Destroy the key
  • 116. One-­‐Time pad
  • 117. This is provably perfectly secure You can’t even brute force it!
  • 118. This is provably perfectly secure opuxgvcbarmy owbxelcixrql ------------ - attackatdawn opuxgvcbarmy elqinoymwrku ------------ - keepthepeace
  • 119. This is provably perfectly secure So why don’t we all use it?
  • 120. Why we don’t use it: You need to share the key securely, But how?
  • 121. Out of band communica(on How the spies did it Before the mission, they received a codebook
  • 122. Out of band communica(on How the spies did it But imprac(cal for ordinary use
  • 123. In band communica(on Safe channel through which to send the key
  • 124. In band communica(on Just use that channel to send the message.
  • 125. They all have in common: Confusion ✓ Diffusion ✗
  • 126. Why do you need diffusion? e.g. image encryp(on
  • 127. Using a block cipher Encodes blocks of data
  • 128. Electronic Code Book (ECB) Blocks with the same data are encoded as the same data
  • 129. Encode this image with ECB: 24-­‐bits bmp
  • 130. “Encrypted” (a`er header restora(on)
  • 131. Cipher block chaining Does do diffusion
  • 132. Looks like noise.
  • 133. Methods covered so far: Brute Force Caesar Cipher
  • 134. Methods covered so far: Brute Force Caesar Cipher Founda(onal weakness Vigenère, Subs9tu9on, ECB
  • 135. Next up: Mad Science
  • 136. Next up: Mad Science Side channel a=acks
  • 137. Tradi(onal model Plaintext E Key Ciphertext D Key Plaintext
  • 138. Side channel model Plaintext E Key Ciphertext D Key Plaintext Heat Timing Heat Timing
  • 139. Simple example def __eq__(self, other): if len(self) != len(other): return False for x,y in zip(self, other): if x != y: return False return True
  • 140. Simple example if input == password: login() else: error()
  • 141. Simple example 1000 * input = '-' Wall time: 817 μs 1000 * input = '--' Wall time: 2.14 ms 1000 * input = '---' Wall time: 806 μs def __eq__(self, other): if len(self) != len(other): return False for x,y in zip(self, other): if x != y: return False return True
  • 142. Simple example 1000 * input = '-' Wall time: 817 μs 1000 * input = '--' Wall time: 2.14 ms 1000 * input = '---' Wall time: 806 μs def __eq__(self, other): if len(self) != len(other): return False for x,y in zip(self, other): if x != y: return False return True ≈ 0.8ms
  • 143. Simple example 1000 * input = '-' Wall time: 817 μs 1000 * input = '--' Wall time: 2.14 ms 1000 * input = '---' Wall time: 806 μs def __eq__(self, other): if len(self) != len(other): return False for x,y in zip(self, other): if x != y: return False return True ≈ 2.1ms (1 iter)
  • 144. Simple example 1000 * input = 'a-' Wall time: 2.15 ms 1000 * input = 'b-' Wall time: 2.33 ms 1000 * input = 'c-' Wall time: 2.14 ms def __eq__(self, other): if len(self) != len(other): return False for x,y in zip(self, other): if x != y: return False return True ≈ 2.1ms (1 iter)
  • 145. Simple example 1000 * input = 'a-' Wall time: 2.15 ms 1000 * input = 'b-' Wall time: 2.33 ms 1000 * input = 'c-' Wall time: 2.14 ms def __eq__(self, other): if len(self) != len(other): return False for x,y in zip(self, other): if x != y: return False return True ≈ 2.3ms (2 iter)
  • 146. Simple example 1000 * input = 'ba' Wall time: 2.33 ms 1000 * input = 'bb' LOGGED IN! (2.47 ms) 1000 * input = 'bc' Wall time: 2.32 ms def __eq__(self, other): if len(self) != len(other): return False for x,y in zip(self, other): if x != y: return False return True ≈ 2.3ms (2 iter)
  • 147. Simple example 1000 * input = 'ba' Wall time: 2.33 ms 1000 * input = 'bb' LOGGED IN! (2.47 ms) 1000 * input = 'bc' Wall time: 2.32 ms def __eq__(self, other): if len(self) != len(other): return False for x,y in zip(self, other): if x != y: return False return True ≈ 2.5ms (2 iter)
  • 148. Simple example This simple error has reduced your keyspace From 26n to 26n
  • 149. This isn’t really MAD science…
  • 150. Power consump(on of a CPU during RSA computa(on.
  • 151. 0
  • 152. 0 1 …
  • 153. Crypto is a minefield
  • 154. h=p://www.moserware.com/2009/09/s(ck-­‐figure-­‐guide-­‐to-­‐advanced.html
  • 155. Methods covered so far: Brute Force Caesar Cipher Founda(onal weakness Vigenère, Subs9tu9on, ECB Side channel a=acks Timing, Power Consump9on, Acous9c, etc.
  • 156. Last but not least Rubber-­‐Hose Cryptanalysis
  • 157. [..] In which a rubber hose is applied forcefully and frequently to the soles of the feet, un9l the key to the cryptosystem is discovered A process that can take a surprisingly short 9me and is quite computa9onally inexpensive sci.crypt (1990)
  • 158. What haven’t I covered? Asymmetric encryp(on public – private key … A lot of math Diffie – Hellman key exchange Prime factoriza(on Ellip(c Curve crypto … Integrety assurance HMAC … Stream Ciphers Man in the middle AES, DES, Hashes Salts Etc.
  • 159. MORE!!! Great intro to a great encryp(on standard A s(ck figure guide to AES Awesome primer for InfoSec Mad science side-­‐channel a=acks To Protect and Infect (Jacob Applebaum) History of the informa(on age