mukhya pravah

guptalekhnamadhye, keystream haah yadruchchik kinwa chhadm varnancha eka pravah asato joou eka guptalekhan kelela sandesh (sanketik paath) tayar karnyasathi sadhya majkurachya sandeshasah jodala jaato.
keystream "akshare" heey vapar prakarnanusar bits, bites, sankhya kinwa a-z sarkhya vastavik akshare asoo shakatat.
samanyatah mukhya pravahatil pratyek varn ektar jodale jaate, vaja kele jaate kinwa modular ankganitacha vapar karoon sanketik majkoor tayar karnyasathi sadhya majkuratil varnasah xord kele jaate.
keystreamcha vapar vann-time padd sifermadhye aanee bahutek stream sifermadhye keela jaato. block sayfarcha vapar keystream tayar karnyasathi dekhil keela jaau shakato. udaharanarth, see. tii. aar. mode haah eka block mode aahe joou block cyferla keystream tayar karato aanee asha prakare block cyferla stream sifermadhye rupantarit karato.
udaharanadakhal.
yaa sopya udaharanamadhye aapan a-z madheel 26 varnanchi ingraji varnamala vaparato. asha prakare aapan sankhya, alpaviram, rikt jaaga aanee itar chinhe encrypt karoo shakat nahee. keystream yadruchchik sankhya kiman 0 aanee 25 chya darmyan asavyat.
encrypt karnyasathi aapan plaintextmadhye keystream kramank jodato. aanee decrypt karnyasathi aapan plaintext midvanyasathi cyfertextmadhun samaan keystream sankhya vaja karato.
jarr cyfertext kramank 25 peksha motha jhaala tarr aapan tyala 0-25 chya darmyanchya moolyat gundalato. asha prakare 26 heey 0 hote aanee 27 heey 1 hote aanee asech pudhe. (asha rappingla modular ankganit mhanatat.)
yethe 'pahatecha hallah' haah sadha majkoor sandesh 'kjcngmlhylyu' yaa mukhya pravahasah jodala jaato aanee 'kcvniwlabluh' haah sanketik majkoor tayar karato.

