xtea

guudha lipi saastramlo, xtea (podiginchina tii) anedi tealoni balaheenatalanu saricheyadaaniki roopondinchina block saifar. saanketikalipi yokka roopakartalu cambridge computer prayogasaala yokka david wheeler mariyu roser needham, mariyu algorithm algorithm prachurinchabadani saanketika nivedikalo samarpinchabadindi (needham mariyu wheeler, 1997). idhi yea petentlaku lobadi undadu.
tii maadirigaane, xtea anedi 128-bitt kii mariyu suuchimchina 64 roundlatho kuudina 64-bitt block fistel saifar. tii nundi aneka thedaalu spashtamgaa kanipistaayi, veetilo kontha klishtamaina kii-schedule mariyu shiftulu, jars mariyu cherpula punarvyavastheekarana unnaayi.
amalu.
eee praamaanika sii soars code, david wheeler mariyu roser needham dwara public domainloki vidudala chesina reference code nundi sweekarinchabadindi, xtea upayoginchi encryptlu mariyu decryptlu
/* 64 bits dayta v [0] mariyu v [1] mariyu 128 bits kii [0]-kii [3] loe teesukondi. */
shoonya ensifer (santakam cheyani int num _ rounds, uint32 _ t v [2], uint32 _ t sthiraamkam kii [4]) {
 santakam cheyani intu ii;
 uint32 _ t v0 = v [0], v1 = v [1], mottam = 0, delta = 0x9e3779b9;
 (i = 0; i <num _ rounds; i + +) {
 v0 + = ((v1 "4) ^ (v1" 5) + v1) ^ (mottam + kii [mottam & 3]);
 mottam + = delta;
 v1 + = ((v0 "4) ^ (v0" 5) + v0) ^ (mottam + kii [(mottam "11) & 3]);
 v [0] = v0; v [1] = v1;
shoonya ardhalekhanam (santakam cheyani int num _ rounds, uint32 _ t v [2], uint32 _ t sthiraamkam kii [4]) {
 santakam cheyani intu ii;
 uint32 _ t v0 = v [0], v1 = v [1], delta = 0x9e3779b9, mottam = delta * num _ roundlu;
 (i = 0; i <num _ rounds; i + +) {
 v1-= ((v0 "4) ^ (v0" 5) + v0) ^ (mottam + kii [(mottam "11) & 3]);
 mottam-= delta;
 v0-= ((v1 "4) ^ (v1" 5) + v1) ^ (mottam + kii [mottam & 3]);
 v [0] = v0; v [1] = v1;
reference soars code nundi maarpulu chinnavi
num _ rounds" paramiti kosam sifaarsu cheyabadina viluva 32,64 kaadu, endukante loop yokka prati punaraavrutam rendu feastell-saifar roundlu chestundi. adanamgaa vegaanni meruguparachadaaniki, mottam + kii [] viluvalanu mundugaa ganinchadam dwara loopnu unroll cheyavachu.
guudha lipi vislaeshanha.
2004 loe, koo mariyu itarulu. 64 roundla xtea loe 27 roundlapai sambandhita-kii differential daadini pradarsinchaaru, dheeniki 220.5 enchukunna saadaa paataalu mariyu 2115.15 yokka samaya sanklishtata avasaram.
avasaram, luu 36 roundla roundla sambandhita-kii deerghachaturasrapu daadini samarpinchindi, xtea kosam gatamlo prachurinchina guudha lipi vislaeshanha phalitaala kante ekkuva roundlanu vichchinnam chesindi. paper rendu daadulanu pradarsistundi, okati lekunda mariyu balaheenamaina kii oohatho, idhi varusaga dayta yokka 264.98 baitlu mariyu 2126.44 operationlaku anugunamgaa untundi, mariyu 263.83 dayta baitlu mariyu 2104.33 operationlaku anugunamgaa untundi.
teany block cheyandi.
xtea thoo paatu pradarsinchabadina block tii anie piluvabade variable-vedalpu block saifar, idhi xtea round functionnu upayogistundi, conny block tii aneka punaraavruttula kosam mottam sandesamlo chakreeyamgaa vartistundi. idhi mottam sandesampai panichestundi kabatti, block teeki operation mode avasaram ledani lakshanam undhi. puurti block teepai daadini sarinen varninchaaru, idhi block tii vaarasudaina xxtea loe balaheenatanu kooda vivaristundi.

