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.

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Information security - Paylogic TechTalk 2014

  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

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