App Crypto for Android

ivan gabrovski

Iqukethe izikhangiso

Mayelana nalolu hlelo lokusebenza

Uhlelo lokusebenza luhlinzeka ngezindlela ezilandelayo zokubethela nokususa ukubethela: i-cryptosystem ehambisanayo yombhalo wesiLatini (izinhlamvu ezingama-26), i-cryptosystem ehambisanayo yombhalo wesiCyrillic (izinhlamvu ezingama-30), i-cryptosystem ye-RSA kanye ne-cryptosystem ye-АSE.
I-Affine cryptosystem, izibonelo zama-cryptosystems okhiye oyimfihlo. Ku-cryptosystem yokhiye oyimfihlo, uma usuwazi ukhiye wokubethela, ungathola ngokushesha ukhiye wokukhipha ukubethela. Ngakho-ke, ukwazi ukuthi ungayibhala kanjani imilayezo usebenzisa ukhiye othile kukuvumela ukuthi ukhiphe ukubethela imilayezo ebibethelwe usebenzisa lo khiye.
I-RSA  cryptosystem iyi-cryptosystem yokhiye womphakathi, enye yezindala ezisetshenziswa kakhulu ekudluliselweni kwedatha okuvikelekile. Ku-cryptosystem yokhiye womphakathi, ukhiye wokubethela usesidlangalaleni futhi uhlukile kukhiye wokukhipha ukubethela, ogcinwa uyimfihlo (uyimfihlo). Umsebenzisi we-RSA udala futhi ashicilele ukhiye osesidlangalaleni ngokusekelwe ezinombolweni ezimbili ezinkulu, kanye nenani elisizayo. Izinombolo eziyinhloko zigcinwa ziyimfihlo. Imilayezo ingabethelwa yinoma ubani, ngokhiye osesidlangalaleni, kodwa ingasuswa kuphela umuntu owazi ukhiye oyimfihlo.
I-Advanced Encryption Standard (AES), eyaziwa ngegama layo langempela i-Rijndael  iwukucaciswa kokubethelwa kwedatha ye-elekthronikhi esungulwe yi-U.S. National Institute of Standards and Technology (NIST) ngo-2001. I-AES ihlukile kwe-Rijndael block cipher.  I-Rijndael iwumndeni wama-ciphers anokhiye abahlukene namasayizi webhulokhi.
Kuhlelo lokusebenza kusetshenziswa i-AES/CBC/PKCS5Padding okuyindlela yokusebenza ye-cryptographic esetshenziselwa ukubethela okuvikelekile kanye nokukhipha ukubethela kwedatha. I-CBC (Cipher Block Chaining): lena imodi yokusebenza lapho ibhulokhi ngayinye yedatha ihlanganiswa nebhulokhi yangaphambilini kusetshenziswa ukusebenza kwe-XOR ngaphambi kokuthi ibethelwe. Ibhulokhi yokuqala ihlanganiswe nevekhtha yokuqalisa (IV), okumele ihluke kumlayezo ngamunye obethelwe. Imodi ye-CBC inikeza isivikelo esingcono ekuhlaselweni okuzama ukushintsha okuqukethwe yimilayezo. I-PKCS5Padding: lesi isikimu sokupheda sedatha esiqinisekisa ukuthi idatha yokufaka inobude obuphindaphindwayo kasayizi webhulokhi (kulokhu amabhithi angu-128). I-PKCS5Padding ingeza amabhayithi ekupheleni kwebhulokhi yokugcina ukuze igcwale. Lawa mabhayithi engeziwe aqukethe ulwazi mayelana nenani lamabhayithi angeziwe.
Ngazo zonke izindlela zokubethela kuhlelo lokusebenza, kungenzeka ukugcina amafayela abethelwe ohlwini lwemibhalo olukhethiwe lwedivayisi lapho kukhona ifayela lokubethela, emagameni okunombhalo othi “Ebetheliwe...” kanye nefayela lokubethela igama, kanye kubakaki isandiso salo kanye nendlela yokubethela njenge-AES.
Umbhalo obethelwe ungalondolozwa njengamafayela kufolda yedivayisi yokulanda.
Kuhlelo lokusebenza ukhiye oyimfihlo we-AES ukuze alondolozwe abethelwa ngendlela ye-RSA futhi alondolozwe njengefayela elihlukile. Ngakho ngokubethela kwe-AES kugcinwa amafayela angaphambili anamagama:
EncryptedAes_xxx(.txt).bin – ifayela elibethelwe xxx.txt;
EncryptedAesRSAPrivateKey_xxx.bin – ukhiye oyimfihlo we-RSA wokubethela ukhiye we-AES oyimfihlo wefayela elifanayo xxx.txt;
I-EncryptedAesKey_xxx.bin – ukhiye we-AES oyimfihlo obethelwe ngu-RSAPrivate Key wefayela elifanayo xxx.txt;
ivBin_xxx.bin – i-vector yokuqalisa yefayela elifanayo xxx.txt;
Ngakho ngokubethela kwe-RSA kugcinwa amafayela amathathu anamagama:
EncryptedRSA_xxx(.txt).bin – ifayela elibethelwe xxx.txt;
EncryptedRSAPrivateKey_xxx.bin - ukhiye we-RSA oyimfihlo;
EncryptedRSAPublicKey_xxx.bin - ukhiye we-RSA womphakathi;
Nge-Affine Latin encrypting kugcinwa amafayela amabili anamagama:
EncryptedAffineLatin_xxx(.txt).bin – ifayela elibethelwe xxx.txt;
EncryptedAffineLatinKeyB_xxx.bin - shifting b param;
Isi-Latin sishintsha esimhlophe njenge-Cyrillic ngamafayela abethelwe e-Affine Cyrillic.
Lapho kususwa ukubethela, wonke amafayela endlela yokubethela ehambisanayo kanye nefayela elibethelwe elihambisanayo (ifayela elinedatha ebethelwe kanye nokhiye abahambisanayo) kufanele abe kufolda efanayo.
Lapho kukhethwa indlela esetshenziswa ukubethela ifayela kuqala, ifayela elinedatha ebethelwe liyakhethwa nalo.
Uhlelo lokusebenza lunamabhanela ezikhangiso angenza kusebenze noma kungasebenzi ukuboniswa kwezikhangiso.
Uhlelo lokusebenza lunosizo nezixhumanisi kwezinye izinhlelo zokusebenza zombhali.