Posts for: #RSA

DawgCTF 2021 Writeups

Howdy, We recently participated in DawgCTF 2021 and we got 41st from 595 teams that got 5 points and above, here are some of my writeups and those of some of my teammates. Enjoy Crypto Really Secure Algorithm Points : 150 Challenge Description I like my e’s like I like my trucks: big and obnoxious Author: trashcanna reallysecure Solution we are given the following values n: 1063494238636905330671898279123020701722241177838742822812173978727720269828464796177466331816675300997219760473399150899338190503499441304612339501295713174906319744094945565844664372365921409430229356934682156557249826723147031652843433859344718768493183522524995480377138743798310313783408725321419870843554822150601536373735923419276343616677440442774544203945706641152517137477442684440329779076981535293867470891276594740058202983415251883426242386508849130959905432961654910957147313116759921173654729071152981682554792584462863534617943384988632032130835087976957452863581161399454295389753849954195624356779281196493728732643445649356033158461867533398892265000228558146288424480232820613034689816560319929705959290376265550914058448343308161173100473161643834475548888676356572581129193395124610558172636505697071928778350452726229098387020587814634712035171712313035012109421792643188405752849278190287414108308734638519593282032082768153331276317440224645157072560878195004847185217741752846484430459047014205368551175641186962966731731946128786111994668528579102737764964521437485037695161775036622411218739549286577109028626220150452705854596994751235894610227300222070678106023292138580496517177268042770934391185798181598618563332872419401223903806812404310665174941843727792999745655534108889130325189241267039092501129173520194489329592776789648244263220437261594447066833175026748830694496235756029688061559449109400248449366143822446893851310444152168531390880512280359096438303124398155397910138799660941243464476642041104225318910175143988510614445494598098558426300612294667831401095538851181871031466580808942102239297182977785401087460226345045290147371931284725756179151791539310603340196586480494033673522637677423221202352493653286430691931273676649062037570851083535722738207802574643773975006788646467981693396925922930573766914743566111012462215653872417726475122775377641591778444141816733462035690735543990556767891443301312941168828619850007793197693295002346977318117653857994731382292035666024397790972920502626243999541832942059274728220802530163223188484361653845185336386588669397688474323385816925410493569923865462650449548121898936835205060632513390578074550881170405889665319159308800795056447244869407145217360018494614236328487464266591617854909647808315406639117270321158016494893469025866752746911948790708005075752364953010067274475470453957941422189404716860354111166203043679764568407375052809648827400302926099178569 e: 322080206518256091443899533297838582806903462189212623492459529527398362853578807723331748892091281476489691674322396825893568981731186597175657851460964692083587224231830304595753200276915353388440323973696723177120007866661510911934423352216586106031397002127519163858107192766128665700540985814443511274004469695128927172454976219787146706562954392698315026949257322529441349029783228167181158744356828575460114272675952388130344874175195393881248661753342888300368969470477541152888408256683251028110005741172636776279619483668723660512026112365800539035538500635904281702733475127339140385714006560153071610279780303018848372325359598739283968138816333125764253403325773002607652913882484078902775827169048401031393263955166695217841400017855979724317225872294531492451624247032809524082714281043873127461832051383511298796820369453358960824162684362741938604084210435623099328622028419710290325683380378726085007158903982932912214314158223921219724759717266136246703830446993309980595073110001804483058339461412460693911416430728558495048873597685942089531373734578638349738930086910038003088294940942692030998047041393152747526278088574238755027474019265539054527491401757165011505470582647900401492273402847703170162847259159161319094910753659832147964969052296859561769298825881593753592121708897035728873795159475926749806998737812501868665513946666352941497086651818553871606417281352599234688183547212675353626023151426982640664474136377374110023532481101565870359846621748326349516467938614155834462639061592390266451169971250010491497379073868786106821570448253182042906240682833067783409574735400739329311810053094530811477002973464432651755811246151509011287858077298295987954915889199100328695730233096226912526329144478198121096489396083876129542516602969866961376423685647767885680559757094208574124411496017291060228388949556065235333802142865557844913535276572535282671404020237763405558477020152910105019008364237315330047605257380696367871417207254833979064342650664181309067142909106945469319731754805506564282047041605728503555870882010025649797753726253285119740979484849951129514070748168270413416940958393138417596025358589062839735425553556206423183484639265605269615685651949641759227283257819425264608389110223455267792764547470141745830149226062457331548317230637497633273069300415564503833751637575125936072041989787691982221885384446295804003751739608564016981200019839941768866474797817202494560129096305497153712068566001154013937 c: 329889278578044016824313741527705229624826354380113199851837764563746872233807021113693371778072747023303193661391256917654673579748983619101229337776995574989101525295578632981918777232038222679949264372167418981038519164359046193397794833575692294838270919137212503594644756884879905102382013616716795766055806380675079122193261937202152727372307035197702671407008933906723580158843896939160889881874945976423829414877735269690727711347872615864084627631956403177338185780100778564548976884299086453421725163428017908949325966904530291069025584097022695816511626589485257615664532774194555809017763622197728156453680059300808277471558450818004384751746190317910501772671219117514746584045928056487904112720801176609889740173288130073788687010544220250814378467249611243953690831406523455960639957029937819775398561228599467536715020954136970283137688613486109370883547218314163119613810764259334933209435078926856747403933578685724271075988136268967520808025339001863614193092075106995811355116213778057037256625729238040020810096266917394213617319914026291093309897483557317625696133298013326746629673265558468135602690674704939910172338556035967840157228859997765219241095551758253889312610691956445984657535082546460420349808372702307807697037778668585720318640246334216650054353036505301550387620089144331383076791604944171531121861009872807022569971425034887955393207445086587528972631782104261610625226982484798915695532492666822649105680868782554501246818156815043534857204078057748607289822387462529373683511672270708474273078574153649263666927268413520984191265086647728912692418609093325194826161869428270138209430215739290181617579745939639392608498596400274014103435747462262045586624613109970954762445247628187031774393639286689201449970646288560996969456145518290732375783779950601901268751888374247634804346090070762202809312421725537938059723148831745384765961875359917754708570262909323774973728101735046489385116839098154905761289565030660932858839402457684704605894701939226586411257561719440368089980555960049063794123068432799043630558103308335378100690170353973384441557259766075780510887009923794374174414344793891145106172614982174022423725641446878993111773629101974963001417653742183922637679467704643683488299451383820099923197374567580088833681469257525555566554059017269673597621231456370183587051700138951722854738823417346171701112221512801669470086625272428387110466009926633732340715338158014022960380535876415340423270463298180055 which is vulnerable to wiener attack and we can use this script to uncipher one encryped flag
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Angstrom 2021 Writeups

Hello there,Angstrom 2021 just concluded,with that here are some of writeups that i happened to have a hand in solving and found them interesting. Sosig we are given the following numbers to retreive the flag from,having no source file we kick into research on RSA encryption, this challenge has a weird length of the exponent (e), on researching we found out it might be vulnerable to a Weiner Attack n: 14750066592102758338439084633102741562223591219203189630943672052966621000303456154519803347515025343887382895947775102026034724963378796748540962761394976640342952864739817208825060998189863895968377311649727387838842768794907298646858817890355227417112558852941256395099287929105321231423843497683829478037738006465714535962975416749856785131866597896785844920331956408044840947794833607105618537636218805733376160227327430999385381100775206216452873601027657796973537738599486407175485512639216962928342599015083119118427698674651617214613899357676204734972902992520821894997178904380464872430366181367264392613853 e: 1565336867050084418175648255951787385210447426053509940604773714920538186626599544205650930290507488101084406133534952824870574206657001772499200054242869433576997083771681292767883558741035048709147361410374583497093789053796608379349251534173712598809610768827399960892633213891294284028207199214376738821461246246104062752066758753923394299202917181866781416802075330591787701014530384229203479804290513752235720665571406786263275104965317187989010499908261009845580404540057576978451123220079829779640248363439352875353251089877469182322877181082071530177910308044934497618710160920546552403519187122388217521799 c: 13067887214770834859882729083096183414253591114054566867778732927981528109240197732278980637604409077279483576044261261729124748363294247239690562657430782584224122004420301931314936928578830644763492538873493641682521021685732927424356100927290745782276353158739656810783035098550906086848009045459212837777421406519491289258493280923664889713969077391608901130021239064013366080972266795084345524051559582852664261180284051680377362774381414766499086654799238570091955607718664190238379695293781279636807925927079984771290764386461437633167913864077783899895902667170959671987557815445816604741675326291681074212227 We first verify that the Wiener attack can be applied:
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