Introduction to Cryptography - D334
Questions With Correct Answers
XOR ccthe ccfollowing cc
0101110101010111
1001100000111010
------------------ cc- ccAnswer cc- cc1100010101101101
asymmetric cckey-based ccencryption
-typical ccmethods cc- ccAnswer cc- ccRSA
DSA
El ccGamal
Symmetric cckey-based ccencryption
-Typical ccMethods cc- ccAnswer cc- ccRC2- cc40 ccbit cckey ccsize cc64 ccbit ccblock
RC4- cc(Stream ccCipher)- ccUsed ccin ccSSL ccand ccWEP
RC5- cc(Variable ccKey ccsize, cc32, cc64, ccor cc128 ccbit ccblock ccsize)
AES- cc(128, cc192 ccor cc256 ccbit cckey ccsize, cc128 ccbit ccblock ccsize)
DES- cc(56 ccbit cckey ccsize. cc64 ccbit ccBlock ccsize)
3DES- cc(112 ccbit cckey ccsize, cc64 ccbit ccblock ccsize)
Block ccEncryption cc- ccAnswer cc- ccRC2(40 ccbit cckey ccsize) cc
RC5(Variable ccblock ccsize)
IDEA
DES
,3DES
AES cc(Rijndael)
Blowfish
twofish
stream ccencryption cc- ccAnswer cc- ccRC4
Chacha
Rainbow ccAttack cc- ccAnswer cc- ccThe ccmethod ccof ccknowing ccthe ccmapping ccbetween ccthe cchashed
ccvalues ccand ccthe ccoriginal ccdata
Dictionary-type ccattack cc- ccAnswer cc- cca ccbrute ccforce ccanalysis
∉ cc- ccAnswer cc- ccdoes ccnot ccbelong ccto
when ccan ccobject ccis ccnot ccin cca ccset
∈ cc- ccAnswer cc- ccBelongs ccto
when ccan ccobject ccis ccwithin cca ccset
⊆ cc- ccAnswer cc- ccsubset
subset cchas ccfewer ccelements ccor ccequal ccto ccthe ccset
A cc∪ ccB cc- ccAnswer cc- ccunion cc(objects ccthat ccbelong ccto ccset ccA ccor ccset ccB)
| cc- ccAnswer cc- ccsuch ccthat
A cc∩ ccB cc- ccAnswer cc- ccIntersection: ccin ccboth ccA ccand ccB
, Enigma ccMachine cc-Cypher cc10 cc- ccAnswer cc- ccUsed cca ccpolyalphabetic ccsubstitution cccipher, ccwhich
ccdid ccnot ccrepeat ccwithin cca ccreasonable cc time ccperiod, ccalong ccwith cca ccsecret cckey. ccFor ccthe
cccracking ccof cc the cc Enigma cccipher, cc the cc challenge ccwas ccthus ccto ccdetermine ccboth ccthe
ccalgorithm ccused ccand ccthe cckey. ccEnigma's ccmain ccweakness, ccthough, ccwas ccthat cc none cc of cc the
ccplain cctext ccletters cccould cc be ccciphered ccas ccitself.
Four-square cccipher9 cc- ccAnswer cc- ccUses ccfour cc5 cc× cc5 ccmatrices ccarranged ccin cca ccsquare, ccare
ccwhere cceach ccmatrix cc contains cc 25 ccletters ccfor ccencoding ccand ccdecoding ccoperations.
One-time ccpad cccypher8 cc- ccAnswer cc- ccCypher ccCode ccmapping ccthat ccis cconly ccused cconce. cc
Advantage: ccit ccis ccessentially ccunbreakable. cc
Disadvantage: ccit cctakes cclots ccof ccwork ccas ccyou ccwould cchave ccto ccgenerate ccthe ccpad ccto ccbe
ccused, cceach cctime.
Vigenere ccCipher cc7 cc- ccAnswer cc- ccPolyalphabetic cccipher ccthat ccinvolves ccusing cca ccdifferent
ccmapping, ccbased ccon cca cckeyword, ccfor cceach cccharacter ccof ccthe cccipher. ccAn ccadvantage ccof
ccthis cctype cc of cc cipher ccis ccthat cc the ccsame cc plaintext cccharacter ccis cclikely ccto ccbe cccoded cc to
ccdifferent ccmappings, ccdepending ccon cc the ccposition ccof ccthe cckeyword, ccmaking ccguessing ccmore
ccdifficult.
Ceasar ccCipher6 cc- ccAnswer cc- ccMono-alphabetic ccsubstitution cccipher ccknown ccas cc"shift" cccipher.
ccInvolves ccplaintext ccbeing ccreplaced ccby cca ccletter ccsome ccfixed ccnumber ccof cc positions ccdown
ccthe ccalphabet. cci.e., cca ccCaesar ccCipher ccusing cca ccshift ccof cc+3 ccwould ccmean cca ccplaintext ccletter
ccA ccwould ccresult ccin cca ccciphertext ccletter cc D cc(a cc shift ccof cc three ccpositions ccto ccthe ccright ccin
ccthe ccalphabet)
Morse ccCode cccipher cc5 cc- ccAnswer cc- ccEncoding ccmethod, ccrather ccthan cca cccipher, ccthat ccworks
ccby cctranslating cccharacters ccinto ccsequences ccof cc dots cc(.) ccand ccdashes cc(-)
Playfair ccCipher cc4 cc- ccAnswer cc- cc5 cc× cc5 ccmatrix cccontaining ccthe ccalphabet ccless ccthe ccletter ccJ.
ccCipher/decipher ccprocess cc consists ccof cca ccset cc of ccrules ccoutlining ccuse ccof cccolumn ccand ccrow
cccombinations.
BIFID ccCipher cc3 cc- ccAnswer cc- ccMakes ccuse ccof cca ccgrid ccand ccwhich ccmaps ccthe ccletters ccinto
ccnumeric ccvalues.
Questions With Correct Answers
XOR ccthe ccfollowing cc
0101110101010111
1001100000111010
------------------ cc- ccAnswer cc- cc1100010101101101
asymmetric cckey-based ccencryption
-typical ccmethods cc- ccAnswer cc- ccRSA
DSA
El ccGamal
Symmetric cckey-based ccencryption
-Typical ccMethods cc- ccAnswer cc- ccRC2- cc40 ccbit cckey ccsize cc64 ccbit ccblock
RC4- cc(Stream ccCipher)- ccUsed ccin ccSSL ccand ccWEP
RC5- cc(Variable ccKey ccsize, cc32, cc64, ccor cc128 ccbit ccblock ccsize)
AES- cc(128, cc192 ccor cc256 ccbit cckey ccsize, cc128 ccbit ccblock ccsize)
DES- cc(56 ccbit cckey ccsize. cc64 ccbit ccBlock ccsize)
3DES- cc(112 ccbit cckey ccsize, cc64 ccbit ccblock ccsize)
Block ccEncryption cc- ccAnswer cc- ccRC2(40 ccbit cckey ccsize) cc
RC5(Variable ccblock ccsize)
IDEA
DES
,3DES
AES cc(Rijndael)
Blowfish
twofish
stream ccencryption cc- ccAnswer cc- ccRC4
Chacha
Rainbow ccAttack cc- ccAnswer cc- ccThe ccmethod ccof ccknowing ccthe ccmapping ccbetween ccthe cchashed
ccvalues ccand ccthe ccoriginal ccdata
Dictionary-type ccattack cc- ccAnswer cc- cca ccbrute ccforce ccanalysis
∉ cc- ccAnswer cc- ccdoes ccnot ccbelong ccto
when ccan ccobject ccis ccnot ccin cca ccset
∈ cc- ccAnswer cc- ccBelongs ccto
when ccan ccobject ccis ccwithin cca ccset
⊆ cc- ccAnswer cc- ccsubset
subset cchas ccfewer ccelements ccor ccequal ccto ccthe ccset
A cc∪ ccB cc- ccAnswer cc- ccunion cc(objects ccthat ccbelong ccto ccset ccA ccor ccset ccB)
| cc- ccAnswer cc- ccsuch ccthat
A cc∩ ccB cc- ccAnswer cc- ccIntersection: ccin ccboth ccA ccand ccB
, Enigma ccMachine cc-Cypher cc10 cc- ccAnswer cc- ccUsed cca ccpolyalphabetic ccsubstitution cccipher, ccwhich
ccdid ccnot ccrepeat ccwithin cca ccreasonable cc time ccperiod, ccalong ccwith cca ccsecret cckey. ccFor ccthe
cccracking ccof cc the cc Enigma cccipher, cc the cc challenge ccwas ccthus ccto ccdetermine ccboth ccthe
ccalgorithm ccused ccand ccthe cckey. ccEnigma's ccmain ccweakness, ccthough, ccwas ccthat cc none cc of cc the
ccplain cctext ccletters cccould cc be ccciphered ccas ccitself.
Four-square cccipher9 cc- ccAnswer cc- ccUses ccfour cc5 cc× cc5 ccmatrices ccarranged ccin cca ccsquare, ccare
ccwhere cceach ccmatrix cc contains cc 25 ccletters ccfor ccencoding ccand ccdecoding ccoperations.
One-time ccpad cccypher8 cc- ccAnswer cc- ccCypher ccCode ccmapping ccthat ccis cconly ccused cconce. cc
Advantage: ccit ccis ccessentially ccunbreakable. cc
Disadvantage: ccit cctakes cclots ccof ccwork ccas ccyou ccwould cchave ccto ccgenerate ccthe ccpad ccto ccbe
ccused, cceach cctime.
Vigenere ccCipher cc7 cc- ccAnswer cc- ccPolyalphabetic cccipher ccthat ccinvolves ccusing cca ccdifferent
ccmapping, ccbased ccon cca cckeyword, ccfor cceach cccharacter ccof ccthe cccipher. ccAn ccadvantage ccof
ccthis cctype cc of cc cipher ccis ccthat cc the ccsame cc plaintext cccharacter ccis cclikely ccto ccbe cccoded cc to
ccdifferent ccmappings, ccdepending ccon cc the ccposition ccof ccthe cckeyword, ccmaking ccguessing ccmore
ccdifficult.
Ceasar ccCipher6 cc- ccAnswer cc- ccMono-alphabetic ccsubstitution cccipher ccknown ccas cc"shift" cccipher.
ccInvolves ccplaintext ccbeing ccreplaced ccby cca ccletter ccsome ccfixed ccnumber ccof cc positions ccdown
ccthe ccalphabet. cci.e., cca ccCaesar ccCipher ccusing cca ccshift ccof cc+3 ccwould ccmean cca ccplaintext ccletter
ccA ccwould ccresult ccin cca ccciphertext ccletter cc D cc(a cc shift ccof cc three ccpositions ccto ccthe ccright ccin
ccthe ccalphabet)
Morse ccCode cccipher cc5 cc- ccAnswer cc- ccEncoding ccmethod, ccrather ccthan cca cccipher, ccthat ccworks
ccby cctranslating cccharacters ccinto ccsequences ccof cc dots cc(.) ccand ccdashes cc(-)
Playfair ccCipher cc4 cc- ccAnswer cc- cc5 cc× cc5 ccmatrix cccontaining ccthe ccalphabet ccless ccthe ccletter ccJ.
ccCipher/decipher ccprocess cc consists ccof cca ccset cc of ccrules ccoutlining ccuse ccof cccolumn ccand ccrow
cccombinations.
BIFID ccCipher cc3 cc- ccAnswer cc- ccMakes ccuse ccof cca ccgrid ccand ccwhich ccmaps ccthe ccletters ccinto
ccnumeric ccvalues.
