Abaphandi basePoland bacebise indlela entsha yothungelwano lwe-steganography esekelwe kwiimpawu zokusebenza ze-protocol ye-TCP esetyenziswa ngokubanzi. Ababhali bomsebenzi bakholelwa ukuba isikimu sabo, umzekelo, sinokusetyenziselwa ukuthumela imiyalezo efihliweyo kumazwe azimeleyo anyanzelisa ukujongwa okungqongqo kwi-Intanethi. Makhe sizame ukufumanisa ukuba yintoni kanye kanye into entsha kwaye iluncedo kangakanani na.
Okokuqala, kufuneka uchaze ukuba yintoni i-steganography. Ke, i-steganography yinzululwazi yokuhanjiswa komyalezo ofihliweyo. Oko kukuthi, ukusebenzisa iindlela zakhe, amaqela azama ukufihla eyona nyani yokudluliselwa. Lo ngumahluko phakathi kwesi sayensi kunye ne-cryptography, ezama yenza umxholo womyalezo ungafundeki. Kuyaphawuleka ukuba uluntu lobuchwephesha bee-cryptographer luyayidelela kakhulu i-steganography ngenxa yokusondela kweengcinga zayo kumgaqo othi "Ukhuseleko ngokufihlakala" (Andazi ukuba ivakala njani ngokuchanekileyo kwisiRashiya, into efana "noKhuseleko ngokungazi. β). Lo mgaqo, umzekelo, usetyenziswa yiSkype Inc. - ikhowudi yomthombo we-dialer eyaziwayo ivaliwe kwaye akukho mntu uyazi ngokwenene ukuba idatha ibethelwe njani. Kutshanje, ngendlela, i-NSA yakhalaza ngale nto, njengoko kuphawulwe yingcali edumileyo uBruce Schneier. kwiblogi yam.
Ukubuyela kwi-steganography, siya kuphendula umbuzo: kutheni kuyimfuneko ukuba kukho i-cryptography? Ngenene, ungafihla umyalezo usebenzisa i-algorithm yangoku kwaye ukuba usebenzisa isitshixo eside ngokwaneleyo, akukho mntu uya kukwazi ukufunda lo myalezo ngaphandle kokuba uyawufuna. Nangona kunjalo, ngamanye amaxesha kubaluleke kakhulu ukufihla eyona nyani yokudluliselwa okuyimfihlo. Umzekelo, ukuba abasemagunyeni abafanelekileyo babambe umyalezo wakho ofihliweyo kwaye abakwazi ukuwuchaza, kodwa bafuna ngokwenene, emva koko, kukho iindlela ezingezizo zekhompyuter zokuphembelela kunye nokufumana ulwazi. Kuvakala i-dystopian, kodwa, uyabona, oku kunokwenzeka ngokomgaqo. Ngoko ke, kuya kuba bhetele ukuqinisekisa ukuba abo bangafanelekanga ukuba bazi konke ukuba udluliselo lwenziwe. Abaphandi basePoland bacebise indlela enjalo. Ngapha koko, bacebisa ukwenza oku besebenzisa iprotocol esetyenziswa ngumsebenzisi we-Intanethi kangangewaka ngemini.
Apha sisondela kwiProtocol yoLawulo loThutho (TCP). Ukuchaza zonke iinkcukacha zayo, ngokuqinisekileyo, akukho ngqiqo - ide, idiza, kwaye abo bayidingayo sele beyazi. Ngamafutshane, sinokuthi i-TCP yi-protocol yezothutho (oko kukuthi, isebenza "ngaphaya" kwe-IP kunye ne "phantsi" iiprotokholi zomaleko wesicelo, ezifana ne-HTTP, i-FTP okanye i-SMTP), eqinisekisa ukuhanjiswa okuthembekileyo kwedatha evela kumthumeli ukuya. umamkeli. Ukuhanjiswa okuthembekileyo kuthetha ukuba ukuba ipakethi ilahleka okanye ifike iguqulwe, i-TCP iya kunyamekela ukuthunyelwa kwepakethi. Qaphela ukuba utshintsho kwipakethe apha aluthethi ukugqwetha ngabom kwedatha, kodwa iimpazamo zokudlulisa ezenzeka kwinqanaba lomzimba. Umzekelo, ngelixa ipakethi yayihamba ngeengcingo zobhedu, amasuntswana ambalwa atshintshe ixabiso lawo ukuya kwelinye okanye alahleka ngokupheleleyo phakathi kwengxolo (ngendlela, ngenxa ye-Ethernet i-Bit Error Rate ixabiso lidla ngokuthathwa malunga ne-10-8. ). Ukulahleka kwepakethi kuhambo kukwayinto eqhelekileyo kwi-Intanethi. Inokwenzeka, umzekelo, ngenxa yomthwalo kwii-routers, ezikhokelela ekuphuphumeni kwe-buffer kwaye, ngenxa yoko, ukulahlwa kwazo zonke iipakethi ezisanda kufika. Ngokuqhelekileyo, umlinganiselo weepakethi ezilahlekileyo malunga ne-0.1%, kwaye ngexabiso leepesenti ezimbalwa, i-TCP iyeka ukusebenza ngokuqhelekileyo - yonke into iya kucotha kakhulu kumsebenzisi.
Ngaloo ndlela, siyabona ukuba ukuthunyelwa (ukuhanjiswa kwakhona) kweepakethi yinto eqhelekileyo ye-TCP kwaye, ngokubanzi, iyimfuneko. Ngoko kutheni ungayisebenzisi kwiimfuno ze-steganography, kunikwe ukuba i-TCP, njengoko kuphawulwe ngasentla, isetyenziswe kuyo yonke indawo (ngokweengqikelelo ezahlukeneyo, namhlanje isabelo se-TCP kwi-Intanethi sifikelela kwi-80-95%). Undoqo wendlela ecetywayo kukuthumela umyalezo othunyelweyo hayi into ebikwipakethi yokuqala, kodwa idatha esizama ukuyifihla. Nangona kunjalo, ukufumana indawo enjalo akulula kangako. Emva kwayo yonke loo nto, kufuneka wazi ukuba ujonge phi - inani loqhagamshelo lwe-TCP ngaxeshanye oludlula kumnikezeli likhulu kakhulu. Ukuba uyayazi inqanaba eliqikelelweyo lokugqithiselwa kwakhona kwinethiwekhi, ungahlengahlengisa indlela yokuhanjiswa kwe-steganographic ukuze uqhagamshelo lwakho lungohlukanga kwabanye.
Kakade ke, le ndlela ayikhululekile kwiintsilelo. Ngokomzekelo, ukusuka kwimbono ebonakalayo, ukuyiphumeza akuyi kuba lula - kuya kufuna ukutshintsha isitakhi sothungelwano kwiinkqubo zokusebenza, nangona kungekho nto inzima malunga nale nto. Ukongeza, ukuba unemithombo eyaneleyo, kusenokwenzeka ukuba ufumane iipakethi "eziyimfihlo" ngokujonga kunye nokuhlalutya yonke ipakethe kwinethiwekhi. Kodwa njengomthetho, oku akunakwenzeka, ngoko bahlala bejonga iipakethi kunye noqhagamshelo oluvela ngandlela thile, kwaye indlela ecetywayo yiyo kanye eyenza uxhulumaniso lwakho lungabonakali. Kwaye akukho mntu ukunqandayo ekubetheleni idatha eyimfihlo ukuba kunokwenzeka. Kwangaxeshanye, uqhagamshelo ngokwalo lunokuhlala lungafihlwanga ukuze luvuse ukukrokra okuncinci.
Ababhali bomsebenzi (ngendlela, kwabo banomdla, she) ubonise kwinqanaba lokulinganisa ukuba indlela ecetywayo isebenza njengoko kucetywayo. Mhlawumbi kwixesha elizayo umntu uya kuphumeza ingcamango yabo ekusebenzeni. Kwaye ke, ngethemba, kuya kubakho ucelomngeni oluncinci kwi-Intanethi.
umthombo: www.habr.com