Kriptografi
Anggota Kelompok :
Afif Rizka W
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M0509004
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Anis Fagustina
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M0509010
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Dyah Pratiwi
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M0509024
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Khoirul S
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M0509040
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JURUSAN INFORMATIKA
FAKULTAS
MATEMATIKA DAN ILMU PENGETAHUAN ALAM
UNIVERSITAS
SEBELAS MARET
SURAKARTA
2011
CHIPERTEXT 2
Chippertext awal :
waenuktaxnse, xau xdi mwzgdwg kc nagnxazdt wkigi ka
nakugwugi wkbbjdzwxuzkdm zdugdigi uk yg zdugqqztzyqg kdqe uk usg ngamkd
nkmmgmmzdt x pge. waenuktaxnse (taggp paenukm, “mgwagu”; taxnskm, “razuzdt”)
agcgam ykus uk
usg nakwgmm ka mpzqq kc wkbbjdzwxuzdt zd ka igwznsgazdt mgwagu razuzdtm
(wkigm, ka wznsgam) xdi uk
usg jmg kc wkigm uk
wkdogau wkbnjugazlgi ixux mk usxu kdqe x mngwzczw agwznzgdu rzqq yg xyqg uk agxi zu
jmzdt x pge (mgg gdwaenuzkd). waenuktaxnsgam wxqq xd kaztzdxq wkbbjdzwxuzkd
usg wqgxaugvu ka nqxzdugvu. kdwg usg kaztzdxq wkbbjdzwxuzkd sxm yggd
mwaxbyqgi ka gdwznsgagi, usg agmjqu zm pdkrd xm usg wznsgaugvu ka waenuktaxb.
usg gdwznsgazdt nakwgmm jmjxqqe zdokqogm xd xqtkazusb xdi x pge. xd
gdwaenuzkd xqtkazusb zm x nxauzwjqxa bguski kc mwaxbyqzdt—x wkbnjuga naktaxb
ka x razuugd mgu kc zdmuajwuzkdm. usg pge mngwzczgm usg xwujxq mwaxbyqzdt
nakwgmm. usg kaztzdxq wkbbjdzwxuzkd bxe yg x razuugd ka yakxiwxmu bgmmxtg ka
x mgu kc iztzuxq ixux.
zd zum yakxigmu mgdmg, waenuktaxnse zdwqjigm usg jmg kc
wkdwgxqgi bgmmxtgm, wznsgam, xdi wkigm. wkdwgxqgi bgmmxtgm, mjws xm uskmg
sziigd zd kusgarzmg zddkwgdu ugvu xdi uskmg razuugd zd zdozmzyqg zdp, igngdi
cka usgza mjwwgmm kd ygzdt jdmjmngwugi. kdwg usge xag izmwkogagi, usge
caghjgduqe xag gxme uk
igwznsga. wkigm, zd rszws nagigugabzdgi rkaim, djbygam, ka mebykqm agnagmgdu
rkaim xdi nsaxmgm, xag jmjxqqe zbnkmmzyqg uk agxi rzuskju usg pge wkigykkp.
waenuktaxnse xqmk zdwqjigm usg jmg kc wkbnjugazlgi gdwaenuzkd uk nakugwu
uaxdmbzmmzkdm kc ixux xdi bgmmxtgm.
ukixe bkmu wkbbjdzwxuzkd qgxogm mkbg pzdi kc agwkaigi
uaxzq. cka gvxbnqg, wkbbjdzwxuzkdm koga ugqgnskdg qzdgm, zdwqjizdt cxvgm xdi
g-bxzq bgmmxtgm, nakijwg x agwkai kc usg ugqgnskdg djbyga wxqqgi xdi usg uzbg
zu rxm wxqqgi. czdxdwzxq uaxdmxwuzkdm, bgizwxq szmukazgm, wskzwgm kc agduxq
bkozgm, xdi gogd ckki wskzwgm bxe yg uaxwpgi ye wagizu wxai agwgznum ka
zdmjaxdwg agwkaim. gogae uzbg x ngamkd jmgm usg ugqgnskdg ka x wagizu wxai,
usg ugqgnskdg wkbnxde ka czdxdwzxq zdmuzujuzkd pggnm x agwkai kc usg djbyga wxqqgi
ka usg uaxdmxwuzkd xbkjdu, qkwxuzkd, xdi ixug. zd usg cjujag, xm ugqgnskdg
dgurkapm ygwkbg iztzuxq, gogd usg xwujxq wkdogamxuzkdm bxe yg agwkaigi xdi
mukagi. xqq kc uszm xbkjdum uk
x tagxu nkugduzxq qkmm kc nazoxwe. waenuktaxnse zm kdg ukkq usxu rzqq yg xyqg
uk
gdmjag bkag nazoxwe. usg xyzqzue uk gdwaenu ixux, wkbbjdzwxuzkdm,
xdi kusga zdckabxuzkd tzogm zdizozijxqm usg nkrga uk agmukag ngamkdxq nazoxwe.
waenuktaxnse zm zbnkauxdu cka
bkag usxd fjmu nazoxwe, skrgoga. waenuktaxnse nakugwum usg rkaqi’m yxdpzdt
memugbm xm rgqq. bxde yxdpm xdi kusga czdxdwzxq zdmuzujuzkdm wkdijwu usgza
yjmzdgmm koga kngd dgurkapm, mjws xm usg zdugadgu. rzuskju usg xyzqzue uk nakugwu
yxdp uaxdmxwuzkdm xdi wkbbjdzwxuzkdm, wazbzdxqm wkjqi zdugacgag rzus usg
uaxdmxwuzkdm xdi mugxq bkdge rzuskju x uaxwg.
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Proses Dekrip :
waenuktaxnse, xau xdi mwzgdwg kc nagnxazdt wkigi ka nakugwugi
CRYPTOGRAPHY, ART AND SCIENCE OF PREPARING CODED OR PROTECTED
wkbbjdzwxuzkdm zdugdigi uk yg zdugqqztzyqg kdqe uk usg ngamkd nkmmgmmzdt
x
COMMUNICATIONS INTENDED TO BE INTELLIGIBLE ONLY TO THE PERSON POSSESSING
A
pge. waenuktaxnse (taggp paenukm, “mgwagu”; taxnskm, “razuzdt”) agcgam
ykus
KEY CRYPTOGRAPHY (GREEK KRYPTOS,
“SECRET”; GRAPHOS, “WRITING”) REFERS BOTH
uk usg nakwgmm ka mpzqq kc wkbbjdzwxuzdt zd ka igwznsgazdt mgwagu
razuzdtm
TO THE PROCESS OR SKILL OF COMMUNICATING IN OR DECIPHERING SECRET
WRITINGS
(wkigm, ka wznsgam) xdi uk usg jmg kc wkigm uk wkdogau wkbnjugazlgi ixux
mk
(CODES, OR CIPHERS) AND TO THE USE OF CODES TO CONVERT COMPUTERIZED DATA
SO
usxu kdqe x mngwzczw agwznzgdu rzqq yg xyqg uk agxi zu jmzdt x pge (mgg
THAT ONLY A SPECIFIC RECIPIENT WILL BE ABLE TO READ IT USING A KEY (SEE
gdwaenuzkd). waenuktaxnsgam wxqq xd kaztzdxq wkbbjdzwxuzkd usg wqgxaugvu
ka
ENCRYPTION). CRYPTOGRAPHERS CALL AN ORIGINAL COMMUNICATION THE CLEARTEXT
OR
nqxzdugvu. kdwg usg kaztzdxq wkbbjdzwxuzkd sxm yggd mwaxbyqgi ka
PLAINTEXT. ONCE THE ORIGINAL COMMUNICATION HAS BEEN SCRAMBLED OR
gdwznsgagi, usg agmjqu zm pdkrd xm usg wznsgaugvu ka waenuktaxb. usg
ENCIPHERED THE RESULT IS KNOWN AS
THE CIPHERTEXT OR CRYPTOGRAM. THE
gdwznsgazdt nakwgmm jmjxqqe zdokqogm xd xqtkazusb xdi x pge. xd
gdwaenuzkd
ENCIPHERING PROCESS USUALLY INVOLVES AN ALGORITHM AND A KEY. AN
ENCRYPTION
xqtkazusb zm x nxauzwjqxa bguski kc mwaxbyqzdt—x wkbnjuga naktaxb ka x
ALGORITHM IS A PARTICULAR METHOD OF SCRAMBLING-A COMPUTER PROGRAM OR A
razuugd mgu kc zdmuajwuzkdm. usg pge mngwzczgm usg xwujxq mwaxbyqzdt
WRITTEN SET OF INSTRUCTIONS. THE KEY SPECIFIES THE ACTUAL SCRAMBLING
nakwgmm. usg kaztzdxq wkbbjdzwxuzkd bxe yg x razuugd ka yakxiwxmu
bgmmxtg
PROCESS. THE ORIGINAL COMMUNICATION MAY BE A WRITTEN OR BROADCAST
MESSAGE
ka x mgu kc iztzuxq ixux.
OR A SET OF DIGITAL DATA.
zd zum yakxigmu mgdmg, waenuktaxnse zdwqjigm usg jmg kc wkdwgxqgi
bgmmxtgm,
IN ITS BROADEST SENSE, CRYPTOGRAPHY INCLUDES THE USE OF CONCEALED
MESSAGES,
wznsgam, xdi wkigm. wkdwgxqgi bgmmxtgm, mjws xm uskmg sziigd zd
kusgarzmg
CIPHERS, AND CODES. CONCEALED MESSAGES, SUCH AS THOSE HIDDEN IN
OTHERWISE
zddkwgdu ugvu xdi uskmg razuugd zd zdozmzyqg zdp, igngdi cka usgza
mjwwgmm
INNOCENT TEXT AND THOSE WRITTEN IN INVISIBLE INK, DEPEND FOR THEIR
SUCCESS
kd ygzdt jdmjmngwugi. kdwg usge xag izmwkogagi, usge caghjgduqe xag gxme
uk
ON BEING UNSUSPECTED. ONCE THEY ARE DISCOVERED, THEY FREQUENTLY ARE EASY
TO
igwznsga. wkigm, zd rszws nagigugabzdgi rkaim, djbygam, ka mebykqm
DECIPHER. CODES, IN WHICH PREDETERMINED WORDS, NUMBERS, OR SYMBOLS
agnagmgdu rkaim xdi nsaxmgm, xag jmjxqqe zbnkmmzyqg uk agxi rzuskju usg
pge
REPRESENT WORDS AND PHRASES, ARE USUALLY IMPOSSIBLE TO READ WITHOUT THE
KEY
wkigykkp. waenuktaxnse xqmk zdwqjigm usg jmg kc wkbnjugazlgi gdwaenuzkd
uk
CODEBOOK. CRYPTOGRAPHY ALSO INCLUDES THE USE OF COMPUTERIZED ENCRYPTION
TO
nakugwu uaxdmbzmmzkdm kc ixux xdi bgmmxtgm.
PROTECT TRANSMISSIONS OF DATA AND MESSAGES.
ukixe bkmu wkbbjdzwxuzkd qgxogm mkbg pzdi kc agwkaigi uaxzq. cka
gvxbnqg,
TODAY MOST COMMUNICATION LEAVES SOME KIND OF RECORDED TRAIL. FOR
EXAMPLE,
wkbbjdzwxuzkdm koga ugqgnskdg qzdgm, zdwqjizdt cxvgm xdi g-bxzq
bgmmxtgm,
COMMUNICATIONS OVER TELLPHONE LINES, INCLUDING FAXES AND E-MAIL
MESSAGES,
nakijwg x agwkai kc usg ugqgnskdg djbyga wxqqgi xdi usg uzbg zu rxm
wxqqgi.
PRODUCE A RECORD OF THE TELEPHONE NUMBER CALLED AND THE TIME IT WAS
CALLED.
czdxdwzxq uaxdmxwuzkdm, bgizwxq szmukazgm, wskzwgm kc agduxq bkozgm, xdi
FINANCIAL TRANSACTIONS, MEDICAL HISTORIES, CHOICES OF RENTAL MOVIES, AND
gogd ckki wskzwgm bxe yg uaxwpgi ye wagizu wxai agwgznum ka zdmjaxdwg
EVEN FOOD CHOICES MAY BE TRACKED BY CREDIT CARD RECEIPTS OR INSURANCE
agwkaim. gogae uzbg x ngamkd jmgm usg ugqgnskdg ka x wagizu wxai, usg
RECORDS. EVERY TIME A PERSON USES THE TELLPHONE OR A CREDIT CARD, THE
ugqgnskdg wkbnxde ka czdxdwzxq zdmuzujuzkd pggnm x agwkai kc usg djbyga
TELLPHONE COMPANY OR FINANCIAL INSTITUTION KEEPS A RECORD OF THE NUMBER
wxqqgi ka usg uaxdmxwuzkd xbkjdu, qkwxuzkd, xdi ixug. zd usg cjujag, xm
CALLED OR THE TRANSACTION AMOUNT, LOCATION, AND DATE. IN THE FUTURE, AS
ugqgnskdg dgurkapm ygwkbg iztzuxq, gogd usg xwujxq wkdogamxuzkdm bxe yg
TELLPHONE NETWORKS BECOME DIGITAL, EVEN THE ACTUAL CONVERSATIONS MAY BE
agwkaigi xdi mukagi. xqq kc uszm xbkjdum uk x tagxu nkugduzxq qkmm kc
RECORDED AND STORED. ALL OF THIS AMOUNTS TO A GREAT POTENTIAL LOSS OF
nazoxwe. waenuktaxnse zm kdg ukkq usxu rzqq yg xyqg uk gdmjag bkag
nazoxwe.
PRIVACY. CRYPTOGRAPHY IS ONE TOOL THAT WILL BE ABLE TO ENSURE MORE
PRIVACY.
usg xyzqzue uk gdwaenu ixux, wkbbjdzwxuzkdm, xdi kusga zdckabxuzkd tzogm
THE ABILITY TO ENCRYPT DATA, COMMUNICATIONS, AND OTHER INFORMATION GIVES
zdizozijxqm usg nkrga uk agmukag ngamkdxq nazoxwe.
INDIVIDUALS THE POWER TO RESTORE PERSONAL PRIVACY.
waenuktaxnse zm zbnkauxdu cka bkag
usxd fjmu nazoxwe, skrgoga. waenuktaxnse
CRYPTOGRAPHY IS IMPORTANT FOR MORE
THAN JUST PRIVACY, HOWEVER. CRYPTOGRAPHY
nakugwum usg rkaqi’m yxdpzdt memugbm
xm rgqq. bxde yxdpm xdi kusga
PROTECTS THE WORLD’S BANKING SYSTEMS
AS WELL. MANY BANKS AND OTHER
czdxdwzxq zdmuzujuzkdm wkdijwu usgza
yjmzdgmm koga kngd dgurkapm, mjws xm
FINANCIAL INSTITUTIONS CONDUCT THEIR
BUSINESS OVER OPEN NETWORKS, SUCH AS
usg zdugadgu. rzuskju usg xyzqzue uk
nakugwu yxdp uaxdmxwuzkdm xdi
THE INTERNET. WITHOUT THE ABILITY TO
PROTECT BANK TRANSACTIONS AND
wkbbjdzwxuzkdm, wazbzdxqm wkjqi
zdugacgag rzus usg uaxdmxwuzkdm xdi mugxq
COMMUNICATIONS, CRIMINALS COULD
INTERFERE WITH THE TRANSACTIONS AND STEAL
bkdge rzuskju x uaxwg.
MONEY WITHOUT A TRACE.
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Plaintext yang di dapat :
CRYPTOGRAPHY, ART AND SCIENCE OF PREPARING CODED OR
PROTECTED COMMUNICATIONS INTENDED TO
BE INTELLIGIBLE ONLY TO THE PERSON POSSESSING A KEY CRYPTOGRAPHY (GREEK KRYPTOS, “SECRET”;
GRAPHOS, “WRITING”) REFERS BOTH TO THE PROCESS OR SKILL OF
COMMUNICATING IN OR DECIPHERING SECRET WRITINGS (CODES, OR CIPHERS) AND TO
THE USE OF CODES TO CONVERT COMPUTERIZED DATA SO THAT ONLY A SPECIFIC
RECIPIENT WILL BE ABLE TO READ IT USING A KEY (SEE ENCRYPTION).
CRYPTOGRAPHERS CALL AN ORIGINAL COMMUNICATION THE
CLEARTEXT OR PLAINTEXT. ONCE THE
ORIGINAL COMMUNICATION HAS BEEN SCRAMBLED OR ENCIPHERED THE RESULT IS KNOWN AS THE CIPHERTEXT OR
CRYPTOGRAM. THE ENCIPHERING PROCESS
USUALLY INVOLVES AN ALGORITHM AND A KEY. AN ENCRYPTION ALGORITHM IS A PARTICULAR
METHOD OF SCRAMBLING-A COMPUTER PROGRAM OR A WRITTEN SET OF
INSTRUCTIONS. THE KEY SPECIFIES THE ACTUAL SCRAMBLING PROCESS. THE ORIGINAL
COMMUNICATION MAY BE A WRITTEN OR BROADCAST MESSAGE OR A SET OF DIGITAL DATA.
IN ITS BROADEST SENSE, CRYPTOGRAPHY INCLUDES THE USE OF
CONCEALED MESSAGES,CIPHERS, AND CODES. CONCEALED MESSAGES, SUCH AS THOSE
HIDDEN IN OTHERWISE INNOCENT TEXT AND THOSE
WRITTEN IN INVISIBLE INK, DEPEND FOR THEIR SUCCESS ON BEING UNSUSPECTED. ONCE
THEY ARE DISCOVERED, THEY FREQUENTLY ARE EASY TO DECIPHER. CODES, IN WHICH
PREDETERMINED WORDS, NUMBERS, OR SYMBOLS REPRESENT WORDS AND
PHRASES, ARE USUALLY IMPOSSIBLE TO READ WITHOUT THE KEY CODEBOOK. CRYPTOGRAPHY
ALSO INCLUDES THE USE OF COMPUTERIZED ENCRYPTION TO PROTECT TRANSMISSIONS OF
DATA AND MESSAGES.
TODAY MOST COMMUNICATION LEAVES SOME KIND OF RECORDED
TRAIL. FOR EXAMPLE, COMMUNICATIONS OVER
TELLPHONE LINES, INCLUDING FAXES AND E-MAIL MESSAGES, PRODUCE A RECORD OF THE
TELEPHONE NUMBER CALLED AND THE TIME IT WAS CALLED. FINANCIAL TRANSACTIONS,
MEDICAL HISTORIES, CHOICES OF RENTAL MOVIES, AND EVEN FOOD CHOICES MAY BE
TRACKED BY CREDIT CARD RECEIPTS OR INSURANCE RECORDS. EVERY TIME A
PERSON USES THE TELLPHONE OR A CREDIT CARD, THE TELLPHONE COMPANY OR
FINANCIAL INSTITUTION KEEPS A RECORD OF THE NUMBER CALLED OR THE TRANSACTION
AMOUNT, LOCATION, AND DATE. IN THE FUTURE, AS TELLPHONE NETWORKS BECOME
DIGITAL, EVEN THE ACTUAL CONVERSATIONS MAY BE RECORDED AND STORED. ALL
OF THIS AMOUNTS TO A GREAT POTENTIAL LOSS OF PRIVACY. CRYPTOGRAPHY IS
ONE TOOL THAT WILL BE ABLE TO ENSURE MORE PRIVACY.THE ABILITY TO ENCRYPT
DATA, COMMUNICATIONS, AND OTHER INFORMATION GIVES INDIVIDUALS THE POWER TO
RESTORE PERSONAL PRIVACY.
CRYPTOGRAPHY IS IMPORTANT FOR MORE THAN JUST PRIVACY, HOWEVER. CRYPTOGRAPHY PROTECTS
THE WORLD’S BANKING SYSTEMS AS WELL. MANY BANKS AND OTHER FINANCIAL INSTITUTIONS CONDUCT THEIR BUSINESS OVER OPEN
NETWORKS, SUCH AS THE INTERNET. WITHOUT THE
ABILITY TO PROTECT BANK TRANSACTIONS AND COMMUNICATIONS, CRIMINALS COULD INTERFERE WITH THE
TRANSACTIONS AND STEAL MONEY
WITHOUT A TRACE.
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CHIPERTEXT 4
Chippertext awal :
waenuxdxqemzm zm usg xau kc xdxqelzdt wznsgaugvu uk gvuaxwu
usg nqxzdugvu ka usg pge. zd kusga rkaim, waenuxdxqemzm zm usg knnkmzug kc
waenuktaxnse. zu zm usg yagxpzdt kc wznsgam. jdigamuxdizdt usg nakwgmm kc
wkig yagxpzdt zm ogae zbnkauxdu rsgd igmztdzdt xde gdwaenuzkd memugb. usg
mwzgdwg kc waenuktaxnse sxm pgnu jn rzus usg ugwsdkqktzwxq gvnqkmzkd kc usg
qxmu sxqc kc usg 20us wgdujae. wjaagdu memugbm aghjzag ogae nkrgacjq wkbnjuga
memugbm uk
gdwaenu xdi igwaenu ixux. rszqg waenuxdxqemzm sxm zbnakogi xm rgqq, mkbg
memugbm bxe gvzmu usxu xag jdyagxpxyqg ye ukixe’m muxdixaim.
ukixe’m waenuxdxqemzm zm bgxmjagi ye usg djbyga xdi
mnggi kc wkbnjugam xoxzqxyqg uk
usg wkig yagxpga. mkbg waenuktaxnsgam ygqzgog usxu usg dxuzkdxq mgwjazue
xtgdwe (dmx) kc usg jdzugi muxugm sxm gdkabkjm, gvuagbgqe nkrgacjq wkbnjugam
usxu xag gduzagqe igokugi uk
waenuxdxqemzm.
usg mjymuzujuzkd wznsgam igmwazygi xykog xag gxme uk yagxp.
ygckag wkbnjugam rgag xoxzqxyqg, gvngau waenuxdxqemum rkjqi qkkp xu
wznsgaugvu xdi bxpg tjgmmgm xm uk rszws qguugam rgag mjymuzujugi
cka rszws kusga qguugam. gxaqe waenuxdxqemzm ugwsdzhjgm zdwqjigi wkbnjuzdt
usg caghjgdwe rzus rszws qguugam kwwja zd usg qxdtjxtg usxu zm ygzdt
zdugawgnugi. cka gvxbnqg, zd usg gdtqzms qxdtjxtg, usg qguugam g, m, u, x, b,
xdi d kwwja bjws bkag caghjgduqe usxd ik h, l, v, e, xdi r. mk, waenuxdxqemum
qkkp xu usg wznsgaugvu cka usg bkmu caghjgduqe kwwjaazdt qguugam xdi xmmztd
usgb xm wxdizixugm uk yg g, m, u, x, b, xdi d. waenuxdxqemum xqmk pdkr usxu
wgauxzd wkbyzdxuzkdm kc qguugam xag bkag wkbbkd zd usg gdtqzms qxdtjxtg usxd
kusgam xag. cka gvxbnqg, h xdi j kwwja uktgusga, xdi mk ik u xdi s. usg
caghjgdwe xdi wkbyzdxuzkdm kc qguugam sgqn waenuxdxqemum yjzqi x uxyqg kc
nkmmzyqg mkqjuzkd qguugam. usg bkag wznsgaugvu usxu zm xoxzqxyqg, usg yguuga
usg wsxdwgm kc yagxpzdt usg wkig.
zd bkigad waenuktaxnszw memugbm, ukk, usg bkag wznsgaugvu usxu zm
xoxzqxyqg uk
usg wkig yagxpga, usg yguuga. cka uszm agxmkd, xqq memugbm aghjzag caghjgdu
wsxdtzdt kc usg pge. kdwg usg pge zm wsxdtgi, dk bkag wznsgaugvu rzqq yg
nakijwgi jmzdt usg ckabga pge. wznsgaugvu usxu zm nakijwgi jmzdt izccgagdu
pgem—xdi caghjgduqe wsxdtgi pgem—bxpgm usg waenuxdxqemu’m uxmp kc wkig
yagxpzdt izcczwjqu.
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Proses Dekrip :
Key yang di dapat
dari penghitungan frekuensi kemunculan adalah sebagai berikut :
u
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51
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T
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m
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39
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S
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x
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35
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A
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a
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35
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R
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k
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29
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O
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z
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29
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I
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d
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28
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N
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e
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26
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Y
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s
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24
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H
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n
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23
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P
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w
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20
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C
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q
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15
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L
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i
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12
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D
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b
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9
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M
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c
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9
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F
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t
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9
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G
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j
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8
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U
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r
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6
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W
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p
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5
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K
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v
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5
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X
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y
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5
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B
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o
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3
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V
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h
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1
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Q
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l
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1
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Z
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f
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0
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J
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waenuxdxqemzm zm usg xau kc
xdxqelzdt wznsgaugvu uk gvuaxwu usg nqxzdugvu
CRYPTANALYSIS IS THE ART OF
ANALYZING CIPHERTEXT TO EXTRACT THE PLAINTEXT
ka usg pge. zd kusga rkaim,
waenuxdxqemzm zm usg knnkmzug kc waenuktaxnse.
OR THE KEY. IN OTHER WORDS CRYPTANALYSIS IS THE OPPOSITE OF
CRYPTOGRAPHY.
zu zm usg yagxpzdt kc wznsgam.
jdigamuxdizdt usg nakwgmm kc wkig yagxpzdt
IT IS THE BREAKING OF CIPHERS.
UNDERSTANDING THE PROCESS OF CODE BREAKING
zm ogae zbnkauxdu rsgd
igmztdzdt xde gdwaenuzkd memugb. usg mwzgdwg kc
IS VERY IMPORTANT WHEN
DESIGNING ANY ENCRYPTION SYSTEM. THE SCIENCE OF
waenuktaxnse sxm pgnu jn rzus
usg ugwsdkqktzwxq gvnqkmzkd kc usg qxmu sxqc
CRYPTOGRAPHY HAS KEPT UP WITH
THE TECHNOLOGICAL EXPLOSION OF THE LAST HALF
kc usg 20us wgdujae. wjaagdu
memugbm aghjzag ogae nkrgacjq wkbnjuga memugbm
OF THE 20TH CENTURY. CURRENT
SYSTEM REQUIRE VERY POWERFUL COMPUTER
SYSTEMS
uk gdwaenu xdi igwaenu ixux.
rszqg waenuxdxqemzm sxm zbnakogi xm rgqq, mkbg
TO ENCRYPT AND DECRYPT DATA.
WHILE CRYPTANALYSIS HAS IMPROVED AS WELL, SOME
memugbm bxe gvzmu usxu xag
jdyagxpxyqg ye ukixe’m muxdixaim.
SYSTEMS MAY EXIST THAT ARE
UNBREAKABLE BY TODAY’S STANDARDS.
ukixe’m waenuxdxqemzm zm
bgxmjagi ye usg djbyga xdi mnggi kc wkbnjugam
TODAY’S CRYPTANALYSIS IS
MEASURED BY THE NUMBER AND SPEED OF COMPUTERS
xoxzqxyqg uk usg wkig yagxpga.
mkbg waenuktaxnsgam ygqzgog usxu usg
AVAILABLE TO THE CODE BREAKER.
SOME CRYPTOGRAPHERS BELIEVE THAT THE
dxuzkdxq mgwjazue xtgdwe (dmx)
kc usg jdzugi muxugm sxm gdkabkjm, gvuagbgqe
NATIONAL SECURITY AGENCY (NSA)
OF THE UNITED STATES HAS ENORMOUS, EXTREMELY
nkrgacjq wkbnjugam usxu xag
gduzagqe igokugi uk waenuxdxqemzm.
POWERFUL COMPUTERS THAT ARE
ENTIRELY DEVOTED TO CRYPTANALYSIS.
usg mjymuzujuzkd wznsgam
igmwazygi xykog xag gxme uk yagxp. ygckag
THE SUBSTITUTION CIPHERS
DESCRIBED ABOVE ARE EASY TO BREAK. BEFORE
wkbnjugam rgag xoxzqxyqg,
gvngau waenuxdxqemum rkjqi qkkp xu wznsgaugvu xdi
COMPUTERS WERE AVAILABLE,
EXPERT CRYPTANALYSTS WOULD LOOK AT CIPHERTEXT AND
bxpg tjgmmgm xm uk rszws
qguugam rgag mjymuzujugi cka rszws kusga qguugam.
MAKE GUESSES AS TO WHICH
LETTERS WERE SUBSTITUTED FOR WHICH OTHER LETTERS.
gxaqe waenuxdxqemzm ugwsdzhjgm
zdwqjigi wkbnjuzdt usg caghjgdwe rzus rszws
EARLY CRYPTANALYSIS TECHNIQUES
INCLUDED COMPUTING THE FREQUENCY WITH WHICH
qguugam kwwja zd usg qxdtjxtg
usxu zm ygzdt zdugawgnugi. cka gvxbnqg, zd
LETTERS OCCUR IN THE LANGUAGE
THAT IS BEING INTERCEPTED. FOR EXAMPLE, IN
usg gdtqzms qxdtjxtg, usg
qguugam g, m, u, x, b, xdi d kwwja bjws bkag
THE ENGLISH LANGUAGE, THE
LETTERS E, S, T, A, M, AND N OCCUR MUCH MORE
caghjgduqe usxd ik h, l, v, e,
xdi r. mk, waenuxdxqemum qkkp xu usg
FREQUENTLY THAN DO Q, Z, X, Y,
AND W. SO, CRYPTANALYSTS LOOK AT THE
wznsgaugvu cka usg bkmu
caghjgduqe kwwjaazdt qguugam xdi xmmztd usgb xm
CIPHERTEXT FOR THE MOST
FREQUENTLY OCCURRING LETTERS AND ASSIGN THEM AS
wxdizixugm uk yg g, m, u, x, b,
xdi d. waenuxdxqemum xqmk pdkr usxu wgauxzd
CANDIDATES TO BE E, S, T, A, M,
AND N. CRYPTANALYSTS ALSO KNOW THAT CERTAIN
wkbyzdxuzkdm kc qguugam xag
bkag wkbbkd zd usg gdtqzms qxdtjxtg usxd kusgam
COMBINATIONS OF LETTERS ARE
MORE COMMON IN THE ENGLISH LANGUAGE THAN OTHERS
xag. cka gvxbnqg, h xdi j kwwja
uktgusga, xdi mk ik u xdi s. usg caghjgdwe
ARE. FOR EXAMPLE, Q AND U OCCUR
TOGETHER, AND SO DO T AND H. THE FREQUENCY
xdi wkbyzdxuzkdm kc qguugam
sgqn waenuxdxqemum yjzqi x uxyqg kc nkmmzyqg
AND COMBINATIONS OF LETTERS
HELP CRYPTANALYSTS BUILD A TABLE OF POSSIBLE
mkqjuzkd qguugam. usg bkag
wznsgaugvu usxu zm xoxzqxyqg, usg yguuga usg
SOLUTION LETTERS. THE MORE
CIPHERTEXT THAT IS AVAILABLE, THE BETTER THE
wsxdwgm kc yagxpzdt usg wkig.
CHANCES OF BREAKING THE CODE.
zd bkigad waenuktaxnszw memugbm, ukk, usg bkag wznsgaugvu
usxu zm xoxzqxyqg
IN MODERN CRYPTOGRAPHIC SYSTEMS, TOO, THE MORE CIPHERTEXT
THAT IS AVAILABLE
uk usg wkig yagxpga, usg yguuga. cka uszm agxmkd, xqq
memugbm aghjzag
TO THE CODE BREAKER, THE BETTER. FOR THIS REASON, ALL
SYSTEMS REQUIRE
caghjgdu wsxdtzdt kc usg pge. kdwg usg pge zm wsxdtgi, dk
bkag wznsgaugvu
FREQUENT CHANGING OG THE KEY. ONCE THE KEY IS CHANGED, NO
MORE CIPHERTEXT
rzqq yg nakijwgi jmzdt usg ckabga pge. wznsgaugvu usxu zm
nakijwgi jmzdt
WILL BE PRODUCED USING THE FORMER KEY. CIPHERTEXT THAT IS
PRODUCED USING
izccgagdu pgem—xdi caghjgduqe wsxdtgi pgem—bxpgm usg
waenuxdxqemu’m uxmp kc
DIFFERENT KEYS-AND FREQUENTLY CHANGED KEYS-MAKES THE
CRYPTANALYST‘S TASK OF
wkig yagxpzdt izcczwjqu.
CODE BREAKING DIFFICULT.
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Plaintext yang didapat :
CRYPTANALYSIS IS THE ART
OF ANALYZING CIPHERTEXT TO EXTRACT THE PLAINTEXT OR THE KEY. IN OTHER
WORDS CRYPTANALYSIS IS THE OPPOSITE OF
CRYPTOGRAPHY.IT IS THE BREAKING OF CIPHERS. UNDERSTANDING THE PROCESS OF CODE
BREAKING IS VERY IMPORTANT WHEN
DESIGNING ANY ENCRYPTION SYSTEM. THE SCIENCE OF CRYPTOGRAPHY HAS KEPT UP
WITH THE TECHNOLOGICAL EXPLOSION OF THE LAST HALF OF THE 20TH CENTURY.
CURRENT SYSTEM REQUIRE VERY POWERFUL
COMPUTER SYSTEMS TO ENCRYPT AND DECRYPT
DATA. WHILE CRYPTANALYSIS HAS IMPROVED AS WELL, SOME SYSTEMS MAY EXIST THAT ARE
UNBREAKABLE BY TODAY’S STANDARDS.
TODAY’S CRYPTANALYSIS IS
MEASURED BY THE NUMBER AND SPEED OF COMPUTERS AVAILABLE TO THE CODE
BREAKER. SOME CRYPTOGRAPHERS BELIEVE THAT THE NATIONAL SECURITY AGENCY
(NSA) OF THE UNITED STATES HAS ENORMOUS, EXTREMELY POWERFUL COMPUTERS THAT
ARE ENTIRELY DEVOTED TO CRYPTANALYSIS.
THE SUBSTITUTION CIPHERS
DESCRIBED ABOVE ARE EASY TO BREAK. BEFORE COMPUTERS WERE AVAILABLE,
EXPERT CRYPTANALYSTS WOULD LOOK AT CIPHERTEXT AND MAKE GUESSES AS TO WHICH
LETTERS WERE SUBSTITUTED FOR WHICH OTHER LETTERS.EARLY CRYPTANALYSIS
TECHNIQUES INCLUDED COMPUTING THE FREQUENCY WITH WHICH LETTERS OCCUR IN THE
LANGUAGE THAT IS BEING INTERCEPTED. FOR EXAMPLE, IN THE ENGLISH LANGUAGE, THE
LETTERS E, S, T, A, M, AND N OCCUR MUCH MORE FREQUENTLY THAN DO Q, Z,
X, Y, AND W. SO, CRYPTANALYSTS LOOK AT THE CIPHERTEXT FOR THE MOST
FREQUENTLY OCCURRING LETTERS AND ASSIGN THEM AS CANDIDATES TO BE E, S, T,
A, M, AND N. CRYPTANALYSTS ALSO KNOW THAT CERTAIN COMBINATIONS OF LETTERS
ARE MORE COMMON IN THE ENGLISH LANGUAGE THAN OTHERS ARE. FOR EXAMPLE, Q AND U
OCCUR TOGETHER, AND SO DO T AND H. THE FREQUENCY AND COMBINATIONS OF
LETTERS HELP CRYPTANALYSTS BUILD A TABLE OF POSSIBLE SOLUTION LETTERS. THE MORE
CIPHERTEXT THAT IS AVAILABLE, THE BETTER THE CHANCES OF BREAKING THE
CODE.
IN MODERN CRYPTOGRAPHIC
SYSTEMS, TOO, THE MORE CIPHERTEXT THAT IS AVAILABLE TO THE CODE BREAKER, THE
BETTER. FOR THIS REASON, ALL SYSTEMS REQUIRE FREQUENT CHANGING OG THE
KEY. ONCE THE KEY IS CHANGED, NO MORE CIPHERTEXT WILL BE PRODUCED USING THE
FORMER KEY. CIPHERTEXT THAT IS PRODUCED USING DIFFERENT KEYS-AND
FREQUENTLY CHANGED KEYS-MAKES THE CRYPTANALYST‘S TASK OF CODE BREAKING DIFFICULT.
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