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WED LUNCH Tome
lly Sectek mescages have been needed in
Af G ond military appets expedally cluring el farts
ines Ciyptoegiapley has if awn. foots in the Eqptian
“perod. 4ooe yea agqo,.and up b the 460%
tape yaphay was. inainly nede dt the Prfechion of
lonal Saute,
Since then because a compidery gna _whemet: ek
fommerte , the privete sector has become the greater
User Of cryphe systems.
come in _|446 When Digpie ard. Helman. nto duc
(eve luhion wr concept ox publi. ip te aphy,
‘Ln mee Rivest , Shombo. eee C4 The
pict produced public hey system aled R&R, The RA
to systema 1s based on 4 i pabracte iby of packeting
lame inte qers, =n Lys :
at i9gs, Elaomal found days ef cryptasy stems bued
on Ascete i a Systewt problems. - lam
ie 193%, N. Koblite inverted a mettod biel. user
elliptic curves . . \
ie tem bay
The. discipline devoted eh setiery Sy tn és called
Kp rolo. ‘ G 4 ‘ayp 1S art loay thot deals tl
dep a It adbdion eS eiipiaas
ee
Gyptoanalycr? = beasecl on beshihg (oe dipeshey) tes
a plainkex , in 4 dphovtex
-
most stiking aid beanie ode history ye egplegaphy Z
e
A Gphetr js 4 method fx cottea hg @ leas message, cullef
a
The eg detem nes the tuangpormation dak iB used.
“The _prcess Of changin plurtex who Ciphovtew 1s called
SP en pate bow
/ Toyerse process Y dan. Ng ti pea tex ck fo plubte
1S called t Ayayplnen Or this is ; 4
The i Cy ice ]
We » be in with ‘seer Systems aed oe mochelar a
anihmelc ‘ “The __ first e theie Inelhade has i foots we
Jubus Caeser,
We start by tranclatng bers inho ranvbesy
ee B P DSB Fasg Haske 3 z
ON | Bo sais Sie eb, 2x5
ix system (plaintex ) tranizonmns one letler of the 4
pluie obyia Pipe, They Ge ace alto aalled men he
dghers.
lek Pe pumerit. Value of G_ planter lodter
C=pumene value & cortespon digg ciphertex ketter
Then 4 triveal encay pin oy “ HE CAN. Do” vats b
HE cAN Da
HE CAN. pa
> 4,%,3,0,)3 3, 1%
» HEAN Do 3 ciphertex hw‘)
C* p+ (mod ae)
He GN bo - HECAN do
abo Bie
Ie
dearsprmnation iS
pes le si@ Cron 26)
x the solet'on pe- FREI fades )
Euchibean Allgoritt. rm ari cherunbe. ke
PLEASE seENP Money |
—€=FPHo (mod 26)
“aphertex is: LIMKG MamFe BExmw.
Meperg4eiykKL m NOPAEST UVWKXYZ
a eo 6 $F TD H R Be S &G G IF H Ao 422BAP IS
LEQ BHAEETEGOFRPJ ER
; Ophes box
FeEXeN zmemk TNHmMG MYzmN
pons by the p latte
MOT REVEAL THE StcevET
Gg af tb (mod Bed
aaP=c-h (mod 26) |
phd a sur thee fee ad=i Cmod we)
Ge ad =\taek
au ~atk eal
Find the dwense o fa and 26 £€
To solve ite eto, Crew 2b)
2D \AALiH DEUS =i
Apply Euchdean — Algarttna worceiny —buchsmeur ey
26 =J-464tt toe fl co
14 = 2-EES = $-2(7-15)
+ =1.5 72 = Jos dat
Seda.a tl - | = 3(14-2:4) -a-t
2 = Ro} , = 3-(9-9-7
= 3:14 ~90ab—/I1)
= Il-|4-8-26
1 fi -26°2 as l
ie) xc=h (mod 26)
-€ Te (mode) =i.
14x21 tavefl a)
“ha atin analy
Studies OF frequenus of Cturencies Of ktters th the ;
Endlisle alphabet show that, hordes, the mock common
lofless one TN, RD, Ay...
ois nprrmation can be used tp decay pe A ulphes hs
in Afpye fansfow akon
Example
Suppose we know thet a shupt dphes C2PtK (moe
was (sed te encrypt fhe dphertext
\WFKMP cESPE CITE dPAFW GECPY
NTASP CTYRX PppdeR PD
making a frequency tulle) that The
ontly oLLuan. gh ile ae
wess “is Theh £ wes transform J
hn IS= 44K Gnod 26) = |
2 k= (nod 2g)
C2Pti (mod 26)
Pech [mee ac)
& RTHEO RY lsu SEFUL FOREN CIPHE |
mM4M EssAG €E¢
makes Senfe on ceggouep ng
ia pext, thar. pe Know tha en apne tangprmaton
BaPth (mod 26) was used ty enapher The Gphertex,
YRTPS ukki7 ‘YGaFv ElYus
ulveu WRIRK
Pe, Sutcc
RYXD JUuRTu
letters, we phd “Kak the mat
ean
es, te Je
“< (fom
ze M4 Oem tes
letter pre L and tha lb
goes ty L and T oes to UY.
os = aPth (mod 26) that
Hath e\| (mod 2c)
and ath =20 (mod 26)
jes Sa = 9 (mad 24)
gints 1s (mod 26)=F
qisi4A =a 2 RY Cmod: 2)
; \)aes = lh (med 264
moe inleechng cause:
The plaindex gw Mnscribect normally inte a jects
pleassined nainoeg & coluwns 4
The key wa Squane gy hunbess whe Aetenmn
ordleg Of the columpy ant & is bated On 4a chee
Requmsel
Suppose the key word 1S
SoRCERY
62F125 +
Coumbesed jy alphabehial ordes of prcedince)
Vie enetpher fhe plunte
LASER BEAMS CAN BE MODULATE TO
MORE INTELLIGENCE THAN RAdTO WAVES
SaRCERY
E341AS5
bbs ER BE
ppegyec AN B
E moduL aA
FEpPTOCA I
BR YmorRE
SMTEUULT
gF NCETH
AN RADE O
WAVES
Enuphenng Consist gy vea ding the plabter Verticallges
exdes oy the nuwlered Glumns.
Cprecter
EcbT™m™ MECAE RKAVOO JEDSA mn =
ENASS
CRNPTOGRAPHY I's
as
Paths - I bS AOA
Beets 2S fella) S-a—G
gersy =? (mod 2d) +O
(Sxtaoy =aS (mod (2) _- &
@x+204=2a2 mod /3 ) - @©
$ee-3 (mod 13)
ax =10 (mod 13)
¥ 2 ap = 20 (moda) Smle Fea (mod iz)
SE (mo ig)
Shad fais »_@ x2. = Q)x2 ies
+42 1 (mod (3)
OS Ys ai Cmael 13)
o 4 24 (mod 3)
Sica the Sold’ ans Ate (154) = (2,7) ae
whee ~=F Gnd 424 (modin) |
he Solve baer systems , it Ig bette, 4 Use 1
Let A, B be, nak metnices with Wea er
by Wapechvelu, We say That
ep A= @ Cnod mi).
if Aj & bz (mod m)
joall (83), leten, 1ejsk,
Examgle oe i" \e e ) (mod i)
The jollowiny hol ds bs
Ty and Bo mer mahns with prep
mad E wares kxP matnox, DR a Pn,
Ae =Bc etnot ov)
DA= DB (mod _m)
Je system Of Ong iuences
Ay C1 +. Ag ty +-..F AnXn = L,
Bie Sint ain ha dh eT ayy No Bald
Am XT, 2%, 4+ ..+ Ant, =b, Ge
is equivodet™ to the matnx Congruene A
(mock +)
If a)e() moa
a
Ss 6
4 6 #
Ran L td
D sider chagraphic Ciphees wher each block % two
¢ baintex & tepluced by a block two ledttes oe apherter
GOLD Zs BURIED 1N ORGNO, we split the
as follans
Go. OL se uk LE OT NO Ro NO
to numerical equivalents
$6 uN, 3 8% Lao 4843 8,18 HIF Be
The key C2 Sh tA, (modas), 0FG 226
#P +15 B (mod 26), 02 6,<Aab
pont blck 14 3 goes hb: 6-26 beaage
6 2 S:1I414-4 ZE (mod 26)
Gs AtIS-+ 225 mod 26)
Continue — and enciphet te ehle béche 4 cbt the
6 AS 1S 2, AB IB a) a 37, 8S ASH My 2) ZF AMM
Translechay back +. lettess
429cxK NvebT tXEOV CReLS RC
for Aeciphe-iny, we piost pres the Aaigrephic ciphee
Sgstew in maki notation :
(2) -(° *) (7) God 26)
4 1S7VR
IF -4
dt Pn eneiphes wake ghow that is P| has mene |
(moet 2c’)
\> et uc
Thas be “fF ta) (mod 2¢ ) a
Ln general gall Hil Cjphes system mM be obtain
upherterts using CEAP (mod 26 )
Whee A is “an nyn mathx , Aek is tduhvely
’ ®
Cc Ef | and Rx }
Gi B
ACZAAP eT (me 26)
> pthc (moel-od
4 arctan
hes Seay a
STOP PAYMENT
dex nunbes became
a = —
oa Ak RO
B + By Ba, Ri
ETNNE PAcwU LA
R |
ex | g _ Omp, Eve
Ain example ea pproveably seeude Cup b system
One-tme pad, which iz a for yy s. rkeqma
The iz Supposedly Useol per the hotiine beh,
and Wich ng fon
Whom A Messanlo P needs to ee sent, it is ] iv
trans ladecl into a bi sting bee, Sey vence of og
Usiig the bneay Cys velen#S Of the letter nun on
Bc peFGHETkemMmN oP ARSTUD
© ' a By -€ C212 F294 a hele ws
© tip 4
Fo Ay
h fandom Seg ilenc€e K g be hi) Is Z ated |
equine Kap fit shangs genet
Sequerrce (s then abded , Le b bit, fo te biha
Representahion Y the plaintext MW (Note that the {
K must cul the Crttve lenge M1),
Then C2 Mth (mod a) for each pair
t
at
xorg ©
We Use the fandom Sequence
are {OO )
K loio1on ©1020
te Cnuphes the word PEG
Pes IS Se AQAA aA oo eotity
LT>¢ = (jo00), = oro00
426 = (ep), = oono
“ig &
(61000 oollo
oil oo Wooo
00/02 Wilo
> we
Suc l, th. ue
o2rcm,
~° (mod 2)
= 21 =25( mod 23)
z 7 (mod.
2 As (mod ay)
ybove Cam i obtained ye
dla, m) =i, thon
: , Lf .
MP a pune, aA el (mod p )
herrenn )
b(as) = $(2*%) 22.946 =a
So =lat¢ fe
Beo =(2")" 27 2O)2% 29 (med 28)
Ane Bl eb ncaa soste
E scam le :
Compute E, o4zt <6 FS where ao cr Cred él
5 21 (mod 260)
2) 436 726 = (ini Noo cop),
a, Bos to =2? 42842 428
2 \geto 2:
a dato Ba ce 6 (neh dao
ar £670 5°z 25
pl aero 5 seus tae
a. Wet 62 (aeJien. a
a sil Ginik
a/ atl
aj ito or zat 261
2( ot)
tle find 3a (mod 2) wet solve
RABY Z| (med 132) i (a3, 122) #1
>> 23% = } 4324
So 232-ay= | Sool a | l26-hs
Za = Gea3dtit )\ 2 t-Geem
2/46 [ vce i
IFa=26+5 = 3/22 -[lF)-
6 =|.6 #1 = 2.23-fae
Non-€e,0
NEG why
x
rt Compost
ALK
oS Fh RI 4 3 2g gy \8g
253TH 34S
Ay Sh my is pune then m8 prime, Precip
fap ¢ I" ape led MesTene primes
fey 4-94 pi2os34
C2/%
aa satiate Bes led 4-56 )
inte cer) =(P-1) (4-1), =42- $8 72436
ig 21 (mod age)
> jed-ayze4 =!
2430 = 344
2) d= 43%
Polga0 > Cz isa0 2 {mod 3533)
2 ogrerl
=> Cc 245 (mod 2637) € =0045
bln) =? nePY
Gs r (mod ey Ss pact (med n)
a cle pe! Cmodn) bat ed abt kelr)
aA ors)
ace” zp “Gned in)
2 cf =F Cwiodw Since a \ loassal n\ \ eu
$n) = (pot) (ga
ef = ( (med tp
P
Wb bec
FistHy din) = ap? cq) =(P-() (y wy =4f 1,
4C4en)) = $4 4,) ~ 94) $ oF O64)
= ach-) £4, -1)
>
= 2P 4,
ay nis hasan in Pag way Hen aluost Cue
Gren ption exponent € wilh have a vem large
elmo den) )
Recall the if He ae A Wz c, avid. ey is
x4 such that 6, xt&s =A
un ne Ewe Odean Algoc then
“Thus ra (é,,€,) =|, we can wate
ext wel pos some zxyeR.
Sup pose i Users S hate the Sanne fs A mea
aA ppcent eyponew ts G
> £2
Suppose he Sanne Message it seek © each, xe
hb the plaintent em Can ba (covered vesthg
Me mer tes = (m&:)* (m®)¥ (meet n)
A, Geks mem" (mod n )
dy Je ts mem? (mod ‘al
=> mm Gm be found
@eR Ca¥
4cd (3,474
H=4.( +! H—-34 =l
A) tt) =!
Bt) :
semels 4
A
dake
oa
Ny 5-9 AP
the word we BIG AN
(med Ny)
Ae er C€*#S" (mod Ng )
dy is Such thab xda=' (med p(a2049))
3h 21 (med 19)2)
2 &da.-loiry = |
3 (-334)-jo1a (4) =I
de = - 334 = 6645 ( mod jolz )
0108, 0¢/2,003 S108!
64S ) ; r
F© (mod (asi) > Ssiol
0103 => S £108
67g
x > $2 ¥53 [i
ola > SZ 61a (mod 106)
001g => § =y a4 (mod og.) > S386)
ol xsd
Ylow S-l0| => C104" Cd i324 )
29529 (mod ig27)
453 3 C2 4637 (mod gaa)
(560 (mod 1824)
Ono stead)
326 Cz 3367
(mod jaay)
= ose
Ciphacteact id Abney u
252 ([Sbe i362
. A, F
Cec * Cmoct rape)
ae? (mod igae)
= /2/
tT 7
lake Ny = S14 Ng = 624
eSa4 @ len lrigte «
:
¢
jatounte ¥ Is
Elementiay jactonhg Methods
the Seau rity of fiSA ancl elated
ope cf oF Ye a Ir cil ) ott
depend a the “eres uty ip factoring
“ The sthnple A> method ii HleA TR VIAL
We succeaiely ty tb dide op by
hh ovder, -
We typlace
a Composite ihdeges nr has a prie
Pe Un’
nt r 5
n by p % Fla, Thon we \ysp
Exa wple
Ee jfache
ally
but Flare Ute El
V3 <6 > 31 must be prime
HU BIR F
Example “Take = #32677
Lin = 8 oS
“Ty 2-235 % #fn
Bute 4 jn n=Fxlote A
Liotewr| = 323
N= FAXtXIA TES
Lvi¢gs% | = ia
Ty 24, i, 13, i+ > A } /49153
buh Itfe4s3 14.153 219- F8F
LIFs?| ~ 98
Ti 11,23 ,. 4 Ahaer
> 43} musk bez, a prme . Hane
lé4 ules
anur
Ti Ma Lity Tesh (2 Fctontadin, )
Tiel Anition Test ps bth. poe all
p
ore BK Ao such» a, then on ib pome.
Ke coll Feemat ts LiHte Theaxew 4
Ty Pr is prime and Ge ® gt tp, 7 =]
anes Gusd: Ad
Tk the cowerse. tne 2 Vad Je giben neg
with (nia) =f srk gee | eee gh als {
The comerse iz palee in general.
@-4.. 37a | @Cmed a) but 4) is not P
eq. 2 = 1. (med Sint) vohuds 2gho lla
x= 27° (med aol) 22 x = ott? Ge
% « “Qbite &
340 =10.7¢ +0
340 = Zo.ll tlo
x =| Geet 4)
Ip =8t2 x =((@7%) j2!.8 att, c Cael
X51 BL b4+ 6.4 4. -l mad am
“Thasiin C Jewaeate Cowegse Fecunvaks itt
Suyppose fa whes ef 4: tach. Ste Se
5 —- oe
bac for eacky pve L Aivicling ere , 4a e
then n is prime ‘
Yoo
We show that ord ac=ne-l, “The Congr “e
that k=
A> and leé & be pame witl, Blk.
1) and at ord alk
£ an a = ete tle
“44 i (med n) by hope si
bite Aad ahd Aor
an. ork, A ae
Bo | ord,
hence Qa is prime q
Na+2 Gs on pitrae: Th
Mee $6 = 2-23
a= 2,3, 4
\ até=<! (mod #2)
he glk si (mod +7)
we an Show aa Fit fay l
Pas < sat (modt?)
6% se, = -1 Col er)
“= 4 ( (mod er)
nett kk pume .
V CP, len bey Fina tty dest )
Be erie 2 yt i hat = PR where CF REI
2k» The integer R's pave i qo an integers q
"Be n) zt whines FIP and ah'sy eat aw}
Nota tis t n-l = FR . Shen F Rep restarts the
factese Dt into pilmes, Gok oh tbe Hees litte
foctrad ma pomes we Thas p-l2FR A
fartonsahen
ta
Example Nn=zasgol
n=l = oz Ye © :
A pettic! fuetriahyr of nw ix n-1 =a38p
itt F zAa@a 2 2*7" Gn bl. ken
Take G23 CExerate nase bi yor Hot eel R.
a=3 ahs Pre “hays Tt)
CPreth-s Bimad ext)
Tesseyn
keg” ont ad
Say pose 4 Grn 4e ze such 4 b a |= =
they, n 8 pr ve
Excmpl g 4
N=iz.ar*H = 33249
tie Porth x fest te show ahi n prime
ov 3328 /%, eee
z = 8 22 = -l) (med 3209)
= n as prime
Dpercke lo est bs ak Leisiencl Crptarag =
Y 0 ¢
The eres op w modufp m | chnoted
lear © x $¢ a®%s1 (modula m),
Nofe that al, 4 | br) » by curlers
a oC
+ fo compute — ehicurete logs i to tabutete
Be fy lex & P-!
R sy (mod an)
DeB=ii (2.23
a\ a 3 ¥ 5 6 + $ 4
Me ori te et Ge NI
hasanye Hhe +tible jn. ondes ay nheasing Velues Of ||
mod P) :
Nw of 4 Steps using the method B poporkonal
hich fs nol pact cad few large P.
26 (med nh) > rehdig ae
erviow __ i ¢4 excher Rotoew
k the fiat App (cath of the Ais rele toy problem
pboarcplay -
se Vind. and Bongant with b exchange a Ser
f choose — hummbers 4 andein whith ae made pobbe.
dl Chooses a andor num her A, Compute $
14) (mod n), and Sends alt Bongam
(2) Bongcun chooses a random numbeg. te Bae
veg? tmed np). and . sods Yb PP
(3) Bongaams comp ues the Key k= Us (qa)?
at
&) Aycnda computes the key keV (4P
Note Kec they ompake the- same hey 4
(a9"=(45)% <4 Cnod a} i
Shes Spy knows 4 cind n, as Wwe ats
fie ui and Vv),
ly the Spy Can solve fhe Aiscreke bs pro ble
a=thd, U gneb the pq can the ropuke a
Altematawery given FP Fn nd 9 4g the §
compude. 4% mod n)
The called he Dipfie- Hillinan probe Pe
conjectured to be eg aviglenr to fhe cArecw
Emerulse 7
0) Using the Digyie-tHillman — **Y agree mad f
COmMman key hak can liz Usea by Ayam Wi
wit, hays azat | b=31, and modulus
9zS., .
Soludtiva
uae (mo los)
uw £4¢) Umeel 102)
Se. Pyanela — Senells uzat + Bongam
Bongam Computes» Keay? 290 (uocl. to9)
€2 , 122, 427, b=2.
E mot sa)
2 (mot <8?
26 8 (mod $3)
Bi, (mod S2\.
m were ateaa Cmod 34)
2
Up Sleanvitss. dnelbod fr fling Apuere legs
a 11) | 1 nding. Daa by K
=9* mot?) Wt wich 4 find ind, 4s
anu WM Ne Can wote 2 =MIgse, whee
)2 fo! A = 4m
Bp EL | and vex Cmodm)
gers y badd?) and ths inwp les that
(2 4g Cmod P) --- Bx
hs method connvts of makhy a takle of Valles 9p
br 0sge Fo and a table gp bales of 4g™
F ny z= w 4 h
pest em-l, and Hen sorting the tables and
x4 the values YX 4 and p hat satlipy # Than
Re vdeo m2 Up] decause phic maker_-fhe
howe ee Same length,
desl, 5
Leb P=37, 922, a~azi-
2: bea?) Cmpl az) => b= aa. lmehgs
Thus tke key is = (2, 22,39)
up pase Bowqcum’s plate wt is Me iq, He Cc
fandom number = 7, Then Y, = 2 gt
el xaat (mod 37)
And 4 2
om 4 =e Iltxaced -dme# 33)
Thes Bsgan senets Ey, tm) = (4, i) ts
janclea Acc hexs with Ded 1%! ) =/-17 H! (mod
' -
rte compicdecdion OF the pl wale key 4 fow ie
Key bes Sa. (mod P) is the discrete logcuta
Sup pose it aS possible to (2,0 v4 the
“A know ledge a a a, 52, den we
compute my 2b (mod pl = ; ’
We alieaty knove fan 9”. Cod
Tc would wean thot we cow <olve
problem ; uk this \ iss .assumed ty be sae Oa
Aisucke log pb lem,
The tandem — nu ber is importerns fee
Value x c shoulsl be uUseel for ach,
planter b
Bit fest te nolo of
elec 2, am elemnerts-
P= < Cucd ff)
eG) = plaihti.xt Cmedl p) cheek
femein ds a
Beg fomete ite then ip peter pla the a?'24 Cool?)
hace.
L iw) =) and a2 en and a a zl Cnod qj
Beers jy nn then on pone
hon van Andwee — pen stpabie schenre
hat, the RSA cand Elqamal schanes, a prvtake key
A t Sigh the__meseaue . ‘fle Sngner could deny serdiag
Iynactusc key clesmay that — bis piwate key hes been Stolen,
Mis: fle uncemble sizmatue selene Y& ba'n-van
fen Cirg0). As its name suggests, ibs hag She inyor tant
“i thet a valid signadre cannot be dene l by fhe
ie Veatfeatin ef the scheme leauilies He co-apercbrrn y |
pes.
Eeheme lenies its Secaunty fon He by picu by Ce tee digerth«
eblem,
a: Agenda ws i es bo slog documents Us “4 the
Bevan Antyesper scheme. She has pable keys ,b, 0), wher
a prime J hus a large ade mod P amd
Bo mck Pp). there a is the private hey.
We assume et P= ag
has * onder q
whee <b. is abe:
let a be the set yp pots SPY
S-4L99%.., 8% Gmod 4)
Suppose
of x ey is the plainterct Message to be og
Then He Aigjted 5 igrnschase is Ysx7 Cmed®
“The veri ytaMn isa
chakenge = Peayorse potoctl
@ Bonga sekets 4wo numbers k, , Ka
) He cOmpuckes
z= ykipke
_ kk, j
and sends
at fands
ont P
zs to Ay anda
) Ayana uns
c =2% ae mod P) i
(te) Ranges Mais, the Siinatude by checking
GC a\sectatal (med?)
622 mot 4
{il
co
We check the 7 Vali ty 8} He Veal cation 3
imed J,
kat med g
\
h
ki
gkalaa) med g
g* (med P)
Hence 4b a Vala siymatwre go Mess ane
wd caphey Cte
F a Caphcny yp
D Ri. a owra 7) ileead ne ECS
hey fandom primes P a G tn RsA, =
Tandon sequene 4 O's emcl |’s can be eS &
e hey fr a one Lbme pad,
i walla leayaes. tan dsm =N2’s te omuluk - ell;
Mi qe eqwaives om CIs < lly |
D pinniey eee wheel, ert. c,
N2%s ome used n Wonke-Casto methacls
wee Age mathemadtral eperativns ilipel
Lea Fnowsn pscucls random ng generehn B fee
conn endrcc| Othe A CPM Lehwsr ine)
| posthe integer mM, tke modulus, ts meth cl uses
ya multifler a, and Gn ynegemnA Co
4
No ave compute f Sequertially : Hoag 4c
1 Sita te, He ~ Coto es) 2¢ hi <M
a sequence of heg ex Ay ay nny Mar
any tue otcun twre na Sequence , then the
2 must kepeak,
Suppor 3. if x Shs zy ; fox. Jé L te, Ye
Xa = Ajty,.. ance ther om oe
pat each Xo, the Sequence must lepeak ‘
's os a
periad othe Sequence Xo, Ty y%ay,-y Lt
infegoc T Such hak Ei pe = i At Oglala
Quest ser : 10
Aihadhio He parse & decmng a, fhe sequeue apy
nes generates boy umis %&=6 ¢: Doe
What is The peste J?
Solidieas
a=5 Cra Wee 14 .
x =6 x, Eox,da 22acie med iglG
%, = $(iedta = lo Kosh. ip) a
%, 216 (med tq) seis wel Wee
XX 216 M26 Ye Fla .28bt ia
The SEGUENLE OF ps Bee peu Pocanden V2 figs
te1s,),4 1%, 1610
feiod Tie
Eweruze
Find pedo gy the Sequence gy gscuclonandl
Senosked X= QjAq=¢ , C4 end nzag
_phea c= 0
eax, (nolm) %,= Az, Cuadn)
Bz (mets) =G? x, (nsdn )
ln © =a" & (nob)
a
Bcd (a,m)=! Han a*z¢ Cmod n) whenovep ke {
mu Mtp le & ad, m.
es artln 4 age ehctinck Crp n) the
1x;4 Fepects ag ae f @ terms,
Mu prime ant a fi @ pomche Yoot mod m,
We will cbbuh a prevderinden Sequence ay (ages
aber, sane of, 4 = P(m) = m-t
CO
have X= aXe +6 Cmod md
% = axX,+c (med m) 202, tiitare Cnodm)
Xy= AX+C sax, +(ltata)e Cmokm)
}
Le =akx + Citatary.4+a™')c Cmod m )
Bibheviuke Ct tutarr.., tak) by Ye aul G&
D
ie (a-l) = (4-1) C lta tars. ta*') (mod m)
a* =i (Mod m)
Ww
j We Can write @ 4
BX = a*®-Ox, +46 Cured m)
=(a-t) ‘the Fat Sie rx. Cro dm) 2] (a-1), rely re
ne
Ofek Cm 4
Then
Lars 2 +4 com) God »)
hope Locad nv)
henre Ler = % Cmokm) — Since Yipes a af
Ts (#0 then this innplies Hat the Sequend|
pesiod € with fe Tim) ,a conkadyMaa a
=o. and Tom) |s as (equired,
(b) roo ¢ = CK U
ketene perio dee sequence J
@) if sek and 39 EX: (med m)
ers “
$ ig a Mu Vp le Op the prod.
(b) The peso Tom) oy ZZ, mod m
op TCRE)
ae alm, aa |m,..., Alm , then
ie azb Umcd m) Hen. d=b Cmackaiin 7
Fro nm the lag (eum a, We See That
to dehemmine the pene d 9 ye te 4 equimce wy ua
pie nawdbess. ?
Ne sina
bets Px bean -ade paling and rex, amet
Up Sl ta +ot4. tq (mad pd)
Jhon
|
/) |
#1 (mod f) Hen Hie pedod & Drcinooll ord, A
Pi a thin the perivd a ie Fuel)
a=) mod 1) Hen He perisl op Ye & 2.
Pla Then Pla, $2
2iratqat.tacita” Grod p)
2\ tat tat!
oe Cmod p”)
\y ; Siriap HL (mod et) ‘7 ete. S peniod oF Y. i 1,
1a i adi (mod a) , then a-l hace an Parse
J, <Itata*t. pat!
ela-ty Cat-) Gned pr)
2
Smallest value a € for Which, “this ain hol 2 iz
op Aw Hen tHe penoal is od, a.
ore Ye =o ip qt ow if a*-, =p Cmed p)
bee Yai ta ta®d tar’ Cod at)
r en the peed oe tke Seguence Ye is Pi if asi (mele)
E xtumn [ues 3, x
* Facdorit akin techy wes
Were permet grin
Prurnatudy test
RSA cxypobyeleon
Chindie. rein deg BResrrema
Diente bg bagel apy Senn — Byamred
No -pweuke -yyntom nukes