I-DES okanye i-DESede , i-algorithm ye-symmetric-key ye-encryption yedatha ye-elektroniki, ngumlandeli we DES(uMgangatho woShicilelo lweDatha) kwaye ibonelela ngoguqulelo oluntsonkothileyo olukhuseleke ngakumbi kune-DES. I-DES yaphula isitshixo esinikezelwe ngumsebenzisi kwizitshixo ezintathu njenge k1, k2, kunye ne-k3. Umyalezo uguqulelwa ngokuntsonkothileyo nge-k1 kuqala, emva koko ucatshulwe nge-k2 kwaye uguqulelwe ngokuntsonkothileyo kwakhona nge-k3. Isayizi yeqhosha le-DESede yi-128 okanye i-192 bit kunye neebhloko ze-64 bit. Kukho iindlela ze-2 zokusebenza-Triple ECB (i-Electronic Code Book) kunye ne-Triple CBC (i-Cipher Block Chaining).
Apha ngezantsi sisixhobo sasimahla se-intanethi esibonelela ngoguqulelo oluntsonkothileyo lwe-DES kunye noguqulelo oluntsonkothileyo ngeendlela ezimbini zokusebenza kuyo nayiphi na itekisi engenanto.
Naliphi na ixabiso eliyimfihlo eliyimfihlo olifakayo, okanye esilivelisayo aligcinwanga kule ndawo, esi sixhobo sinikezelwa nge-URL ye-HTTPS ukuqinisekisa ukuba naziphi na izitshixo ezifihlakeleyo azikwazi ukubiwa.
Uguqulelo oluntsonkothileyo lwe-DES
- Ukhetho Olungundoqo:I-DES isebenzisa izitshixo ezithathu, ezibizwa ngokuqhelekileyo njenge-K1, k2, k3. Isitshixo ngasinye sineebhithi ezingama-56 ubude, kodwa ngenxa yokulingana kwamasuntswana, ubungakanani obusebenzayo besitshixo ngamasuntswana angama-64 ngesitshixo ngasinye.
- Inkqubo yoguqulelo oluntsonkothileyo::
- Fihla nge K1Ibhloko yombhalo ongenanto kuqala iguqulelwe ngokuntsonkothileyo kusetyenziswa isitshixo sokuqala se-K1, ikhokelela kumbhalo ofihlakeleyo C1
- NONEI-C1 iye ikhutshelwe isitshixo sesibini i-K2, ivelisa isiphumo esiphakathi.
- Fihla nge K3:Okokugqibela, isiphumo esiphakathi siguqulelwa ngokuntsonkothileyo kwakhona kusetyenziswa isitshixo sesithathu se-K3 ukuvelisa i-ciphertext yokugqibela C2.
I-DES Decryption
Uguqulelo oluntsonkothileyo kwi-DES yeyona nto ibuyisela umva kuguqulelo oluntsonkothileyo:
- Inkqubo yoguqulelo oluntsonkothileyo:
- NONEI-ciphertext C2 ikhutshiwe kusetyenziswa iqhosha lesithathu le-K3 ukufumana isiphumo esiphakathi.
- Fihla nge K2:Isiphumo esiphakathi siye siguqulelwe ngokuntsonkothileyo kusetyenziswa iqhosha lesibini le K2, livelisa esinye isiphumo esiphakathi.
- NONEOkokugqibela, esi siphumo sicatshulwa kusetyenziswa isitshixo sokuqala se-K1 ukufumana umbhalo ocacileyo wokuqala.
Ulawulo olungundoqo
- Ubungakanani obungundoqo:Isitshixo ngasinye kwi-DES ngamasuntswana angama-56 ubude, okukhokelela kubungakanani bebonke obusebenzayo beqhosha lamasuntswana angama-168 (ekubeni i-K1, i-K2 kunye ne-K3 zisetyenziswa ngokulandelelana).
- Usetyenziso Olungundoqo:I-K1 kunye ne-K3 inokuba sisitshixo esifanayo sokuhambelana nokubuyela umva kunye ne-DES eqhelekileyo, kodwa kuyacetyiswa ukuba i-K2 yahluke ukuphucula ukhuseleko.
Iingqwalasela zoKhuseleko
- I-DES ithathwa njengekhuselekile kodwa iyacotha xa ithelekiswa neendlela zanamhlanje ezifana ne-AES.
- Ngenxa yobude bayo obuphambili, i-3DES isengozini yokuhlaselwa okuthile kwaye ayisakhuthazwa kwizicelo ezitsha apho ezinye iindlela ezingcono (njenge-AES) zikhoyo.
I-DES ihlala isetyenziswa kwiinkqubo zelifa apho ukuhambelana ne-DES kufuneka, kodwa izicelo zangoku zihlala zisebenzisa. I-AES yoguqulelo oluntsonkothileyo ngenxa yokusebenza kakuhle kunye nokhuseleko olomeleleyo.
Isikhokelo sokuSebenzisa kwi-DES Encryption
Ngenisa nasiphi na isicatshulwa esicacileyo okanye igama lokugqitha ofuna ukulifihla. Emva koko, khetha imowudi yoguqulelo oluntsonkothileyo. Ngezantsi ziivale ezinokwenzeka:
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I-ECB: Ngemo ye-ECB, nasiphi na isicatshulwa sahlulwe saba ziibhloko ezininzi, kwaye ibhloko nganye iguqulelwe ngokuntsonkothileyo ngesitshixo esinikiweyo kwaye kungoko iibhloko zeteksti ezifanayo ezingenanto zifihliweyo kwiibhloko zeteksti ze-cipher ezifanayo. Kungoko, le ndlela yoguqulelo oluntsonkothileyo ithathwa njengekhuselekile kancinci kunemo ye-CBC. Akukho IV efunekayo kwimowudi ye-ECB njengoko ibhloko nganye iguqulelwe ngokuntsonkothileyo kwiibhloko zeteksti ze-cipher ezifanayo. Khumbula, ukusetyenziswa kwe-IV kuqinisekisa ukuba imibhalo ecacileyo efanayo ifihliwe kwii-ciphertexts ezahlukeneyo.
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I-CBC: Imodi ye-CBC encryption ithathwa njengekhuselekile ngakumbi xa kuthelekiswa nemodi ye-ECB, njengoko i-CBC ifuna i-IV enceda ekuguquleni i-encryption yeebhloko ezifanayo ngokungafani nemodi ye-ECB. Ubungakanani bevektha yokuqalisa yemo yeCBC kufuneka ibeyi-64 bit okuthetha ukuba kufuneka ibenoonobumba abasi-8 ubude o.t., 8*8 = 64 bits