Nhanganyaya pfupi
Steganography, kana paine asingayeuki, iri kuvanza ruzivo mune mamwe midziyo. Semuenzaniso, mumifananidzo (yakakurukurwa ΠΈ ) Iwe unogona zvakare kuvanza data mumatafura sevhisi yefaira system (izvi zvakanyorwa nezvazvo ), uye kunyange . Nehurombo, nzira dzese idzi dzine chidzoro chimwe chete: kuti ugone "kuisa" ruzivo mumudziyo, iwe unoda hungwaru maalgorithms ayo anofunga nezvehumwe hunhu hwemukati memudziyo. Uye matambudziko anomuka nekupokana kwemudziyo pakugadzirisa: semuenzaniso, kana iwe ukagadzirisa zvishoma mufananidzo, ruzivo rwakavanzika runorasika.
Zvinogoneka kuita neimwe nzira pasina hunyengeri algorithms uye zvinyengeri manipulations nedata, uye uchiri kuona mashandiro emudziyo uye nhanho inogamuchirwa yechengetedzo yedata yakavanzika? Ndichitarisa kumberi, ndichati - hongu, unogona! Ndichatopa zvekushandisa.
Ropa ruzivo rwenzira
Pfungwa yekutanga iri nyore sekurova pahuma: kune nzvimbo dziri pa diski iyo iyo inoshanda sisitimu isinganyore kune (kana kunyora mune zvisingawanzo zviitiko). Kuti tidzivise kukosha kwekutsvaga nzvimbo idzi tichishandisa algorithms ehungwaru, isu tichashandisa redundancy - ndiko kuti, isu tichadzokorora ruzivo rwedu rwakavanzwa kakawanda, kakawanda muzvikamu zvese zve diski. Zvadaro, pamusoro pekubwinya kwese uku, unogona kugadzira zvikamu zvinodiwa, mafomati faira masisitimu, kunyora mafaera uye kuisa maOS - zvese zvakafanana, chikamu che data chakavanzika chichachengetwa uye chinogona kudzoserwa, uye kudzokorora kudzokororwa kuchatibatsira. isai chepakutanga pamwe chete kubva muzvidimbu.
Kubatsira kweiyi nzira kuri pachena: isu hativimbi nefomati yefaira, kana kunyange pamhando yefaira system inoshandiswa.
Izvo zvisingabatsiri zvakare, ndinofunga, zviri pachena:
- Yakavanzika data inogona chete kuchinjwa nekunyora zvachose dhisiki yese, inoteverwa nekudzokorora zvinyorwa zvinoonekwa kumushandisi. Nekudaro, haugone kushandisa software inodzoreredza dhisiki kubva pamufananidzo: inozogadzira zvakare iyo yapfuura yakavanzika data.
- Iyo yakakura vhoriyamu yedata yakavanzika, inowedzera mukana wekurasikirwa neruzivo.
- Kutora data kubva kudhisiki kunogona kutora nguva yakareba. Kubva pamaminetsi akati wandei kusvika mazuva akati wandei (madhisiki emazuva ano akakura).
Iye zvino ngatiendei kune zvakananga.
Zviripachena kuti kana iwe ukangozora yakavanzika data pese pa diski, inongove yakavanzika kubva kune yakashama ziso. Kana iwe ukashongedza maziso ako, taura, dhisiki mupepeti, iyo data ichaonekwa mukubwinya kwayo kose. Naizvozvo, ingave zano rakanaka kuvharidzira iyo data kuti isaratidze. Isu tichanyora zviri nyore, asi zvinonaka: uchishandisa iyo aes256-cbc algorithm. Isu tichabvunza mushandisi kiyi yekuvharira uye rega auye nepassword yakanaka.
Mubvunzo unotevera ndewekuti tingasiyanisa sei "yakanaka" data kubva kune yakaipa data. Pano cheki ichatibatsira, asi kwete iri nyore, asi SHA1. Uye chii? Yakanaka zvakakwana kune git, saka inokodzera isu zvakare. Sarudzo: isu tinopa yega yega yakachengetwa chidimbu cheruzivo necheki, uye kana mushure mekudhipta ichienderana, zvinoreva kuti decryption yakabudirira.
Iwe unozodawo nhamba yechidimbu uye hurefu hwakazara hwe data yakavanzika. Nhamba yechidimbu ndeyekutevera kuti ndezvipi zvimedu zvatatodudzira uye izvo zvasara. Hurefu hwakazara huchatibatsira pakugadzirisa chikamu chekupedzisira, kuitira kuti usanyora zvisina kufanira data (kureva, padding). Zvakanaka, sezvo tichine musoro, tichawedzera zita refaira rakavanzika ipapo. Ichave inobatsira mushure mekunyorwa, kuitira kuti usafungidzire kuti ungaivhura sei.
Kuedza nzira mukuita
Kuti titarise, ngatitorei yakajairika svikiro - flash drive. Ndakawana yekare ine 1 GB kugona, iyo yakanyatsokodzera zviedzo. Kana iwe, seni, wakauya nepfungwa yekusanetseka nevezvenhau, asi kuiyedza pane faira - mufananidzo wedhisiki, ipapo ndichabva ndati: hazvishande. Kana uchigadzira "dhisiki" rakadaro, Linux inogadzira faira zvakare, uye zvikamu zvese zvisina kushandiswa zvichazadzwa ne zero.
Semuchina une Linux, zvinosuruvarisa, ndaifanira kushandisa chiteshi chemamiriro ekunze paRaspberry Pi 3 yakarara pabhakoni. Iko hakuna kurangarira kwakawanda ikoko, saka hatingavanzi mafaira makuru. Isu tinozviganhurira isu pachedu kune yakakura saizi ye10 megabytes. Iko hakuna zvakare chikonzero chekuvanza mafaira ari madiki zvakanyanya: iyo yekushandisa inonyora data kune disk mu4 KB masumbu. Naizvozvo, pazasi isu tichazvimisa isu pachedu kune 3 kb faira - inokodzera mune rimwe sumbu rakadaro.
Isu tichaseka iyo flash drive mumatanho, tichitarisa mushure mechikamu chimwe nechimwe kana iyo yakavanzika ruzivo inoverengwa:
- Kugadzira nekukurumidza muFAT16 fomati ine saizi yesumbu ye16 KB. Izvi ndizvo zvinopihwa neWindows 7 kuita neflash drive isina faira system.
- Kuzadza flash drive nemhando dzese dzemarara ne50%.
- Kuzadza flash drive nemhando dzese dzemarara ne100%.
- "Kureba" fomati muFAT16 fomati (kuwedzeredza zvese).
Miedzo miviri yekutanga, sezvaitarisirwa, yakaguma mukukunda kwakakwana: kushandiswa kwakakwanisa kubudirira kubvisa 10 megabytes ye data yakavanzika kubva kune flash drive. Asi mushure mekunge flash drive yazadzwa kusvika pakukwana nemafaira, kukundikana kwakaitika:
Total clusters read: 250752, decrypted: 158
ERROR: cannot write incomplete secretFile
Sezvauri kuona, masumbu zana nemakumi mashanu nesere chete akaburitswa zvakabudirira (158 kilobytes yedata raw, iro rinopa 632 bytes yemubhadharo). Zviri pachena kuti hapana nzira yekuwana 636424 megabytes pano, uye zvakadaro pakati pemasumbu aya pane zvakajeka zvakapetwa. Iwe haugone kana kudzoreredza 10 megabyte nenzira iyi. Asi isu tinogona kuvimbisa kuti isu tichadzoreredza 1 kilobytes yedata yakavanzika kubva kune flash drive kunyangwe mushure mekurongeka uye kunyorwa kuhuwandu. Nekudaro, zviedzo zvinoratidza kuti zvinokwanisika kubvisa faira 3 kilobytes kureba kubva kune yakadaro flash drive.
Muedzo wekupedzisira, zvinosuruvarisa, wakaratidza kuti flash drive yese yakadhindwa:
$ sudo ./steganodisk -p password /dev/sda
Device size: 250752 clusters
250700 99%
Total clusters read: 250752, decrypted: 0
ERROR: cannot write incomplete secretFile
Hapana kana sumbu rimwe chete rakapona ... Zvinosuruvarisa, asi kwete zvinosuruvarisa! Tisati tagadzirisa, ngatiedzei kugadzira chikamu pane flash drive, uye yatova mairi faira system. Sezvineiwo, yakabva kufekitari iine fomati iyi chaiyo, saka hapana chatinofungira.
Zvinonyatsotarisirwa kuti nzvimbo iripo pane flash drive yadzikira zvishoma.
Zvinotarisirwawo kuti 10 megabytes haigone kuvanzwa pane dhisiki rakazara. Asi ikozvino nhamba yemasumbu akabudirira decrypted yakapetwa kaviri!
Total clusters read: 250752, decrypted: 405
Zvinosuruvarisa, hazvibviri kuunganidza megabyte kubva zvidimbu, asi mazana maviri kilobytes zviri nyore.
Zvakanaka, nhau dzekupedzisira, cheki yechina, ino nguva inofadza: kunyatsogadzirisa flash drive yakadaro hakuna kutungamirira mukuparadzwa kwemashoko ose! 4 kilobytes yedata yakavanzika inokodzera zvakakwana munzvimbo isina kushandiswa.
Tafura yepfupiso yebvunzo:
A little theorizing: nezve nzvimbo yemahara uye zvikamu zvisina kushandiswa
Kana iwe wakambopatsanura hard drive yako kuita partitions, unogona kunge waona kuti hazviiti nguva dzose kugovera nzvimbo yese yemahara pane dhisiki. Chikamu chekutanga chinogara chichitanga neimwe indentation (kazhinji 1 megabyte, kana 2048 sectors). Kuseri kwechikamu chekupedzisira, zvinoitikawo kuti pane kuramba "muswe" muduku wezvikamu zvisina kushandiswa. Uye dzimwe nguva pane mikaha pakati pezvikamu, kunyange zvisingawanzoitiki.
Mune mamwe mazwi, pane zvikamu pa diski zvisingakwanisi kuwanikwa panguva yebasa rakajairwa ne diski, asi data inogona kunyorwa kuzvikamu izvi! Uye izvozvo zvinoreva kuiverengawo. Kugadziriswa nekuda kwekuti kunewo tafura yekuparadzanisa uye kodhi yebhootloader, iyo iri munzvimbo isina chinhu pakutanga kwe diski.
Ngatitorei zororo kubva muzvikamu kwechinguva uye titarise dhisiki kubva paziso reshiri, sekutaura. Pano tine chikamu chisina chinhu pane diski. Ngatigadzirei faira system mairi. Tinogona here kutaura kuti mamwe masekete ari padhisiki anoramba asina kubviswa?
E-e-e - drum roll! Mhinduro inenge iri hongu nguva dzose! Chokwadi, kazhinji, kugadzira faira system kunosvika pakunyora mashoma mabhuraki eruzivo rwesevhisi kune diski, uye kana zvisina kudaro zviri mukati mechikamu hachichinji.
Uye zvakare - zvakachena empirically - tinogona kufunga kuti iyo faira system haigone kugara ichitora nzvimbo yese yakagoverwa kusvika kune yekupedzisira chikamu. Semuyenzaniso, FAT16 faira system ine cluster size ye64 kilobytes zviripachena haigone kugara zvachose muchikamu chine saizi kwete kuwanda kwe64 kilobytes. Pakupera kwechikamu chakadaro panofanirwa kunge paine "muswe" wezvikamu zvakati wandei, zvisingasvikike pakuchengetedza data remushandisi. Zvisinei, fungidziro iyi haina kukwanisa kusimbiswa nekuedza.
Saka, kuti uwedzere nzvimbo iripo yeiyo steganogram, unofanirwa kushandisa faira system ine saizi yakakura yemasumbu. Iwe unogonawo kugadzira chikamu, kunyange kana izvi zvisingakoshi (pane flash drive, somuenzaniso). Hapana chikonzero chekugadzira zvikamu zvisina chinhu kana kusiya nzvimbo dzisina kugoverwa - izvi zvichakwezva kutarisa kwevanhu vanofarira.
Utility for experiments
Iwe unogona kubata iyo kodhi kodhi yekushandisa
Kuvaka, iwe uchada Qt vhezheni 5.0 kana yepamusoro uye OpenSSL. Kana chimwe chinhu chikasashanda, ungangofanira kugadzirisa iyo steganodisk.pro faira.
Unogona kushandura saizi yeboka kubva pa4 KB kuenda, toti, 512 bytes (mu secretfile.h). Panguva imwecheteyo, mari yeruzivo rwebasa ichawedzera: musoro uye cheki inotora yakagadziriswa 68 bytes.
Iwe unofanirwa kumhanyisa zvinoshandiswa, hongu, nemidzi yemushandisi kodzero, uye nekuchenjerera. Pachave pasina mibvunzo inobvunzwa usati wanyora pamusoro faira rataurwa kana mudziyo!
Enjoy.
Source: www.habr.com