I-Encryption

I-**Encryption** ivumela ulwazi ukuba lufihlakale ukuze lungabinakufundwa ngaphandle kokuba kube kukho isitshixo esaziwayo sokuyivula (esinje nge-password). Oku ke kwenziwa ngekhowudi eyimfihlelo okanye nge-cypher. ulwazi olufihliweyo kuthiwa lu- **encrypted**.

I-**Decryption** yindlela yokuguqula ulwazi olu-encrypted ulubuyisela kwi-plaintext. Le ke yindlela e-**decrypted**. Isifundo se-ncryption sibizwa ngokuba yi-cryptography. I-Cryptanalysis ingenziwa ngesandla ukuba i-cypher ilula. Ii-cyphers ezinkulu nezinobunzima zifuna ikhompyutha ukuze zikhangele izitshixo ezinokufumaneka.  I-Decryption licandelo lenzululwazi yekhompyutha ne-mathematika ejonga ukuba zinzima kangakanani na ukuba zingade zophule i-cypher.

## IMIZEKELO
Uhlobo olulula lwamagama e-ncryption y- iROT13.  kwi-ROT13, oonobumba lngokulandelelana kwabo baguqu-guqulwa betshintsisana ngohlobo olunye nolulula. Umzekelo, u-*A* uguqukela ku-*N*, *u-B* uguqukela ku-*O*, u-*C* uguqukela ku-*P*, njalo njalo. Unobumba ngamnye u-"rotated" kwisithuba esili-13.  Ukusebenzisa i-ROT13 cipher, the words *Simple English Wikipedia* becomes *Fvzcyr Ratyvfu Jvxvcrqvn*.  I-ROT13 cipher ilula kakhulu ukuba i-decrypt.  Kuba  bangama-26 oonobumba besiNgesi ngokulandelelana, kuba unobumba ngamnye u-rotated kanibini ngoonobumba abali-13 qho ngexesha. Oyena nobumba wokuqala uzakufumaneka. Ukusebenzisa i-ROT13 cipher okwesibini kubuyisa umbhalo wokuqala. Xa wayethetha nomkhosi wakhe, uJulius Caesar ngamanye amaxesha wayesebenzisa into eyaziwa ngokuba yi-Caesar cipher namhlanje. Le-cipher isebenza ngokususa oonobumba kwiindawo abakuzo: unobumba ngamnye ujikeleziswa kwiindawo ezi-3. 

Iintlobo ezininzi ze-encryption zenziwe zanobunzima ukuze i-cryptanalysis ibenobunzima.  Ezinye zenzelwe amagama kuphela. Ezinye zenzelwe ii-files ze-khompyutha e-binary ezifana nemifanekiso kunye nee-ngoma. Namhlanje, abantu abaninzi basebenzisa inkqubo ye-asymmetric encryption ebizwa ngokuba yi-RSA. Nayiphi na i-file yekhompyutha inga ba-encrypted nge-RSA. i-AES yi-symmetric algorithm exhaphakileyo. 

## I-One-time pad
Inkoliso yeentlobo ze-encryption zisenokwenziwa iintanda ngokwe-thiyori.  Utshaba  lungakwazi uku-decrypt-ha umyalezo ngoku kanye lingayaziyo i-password, ukuba lukrele-krele ngokwemathematika,  ngeekhompyutha ezinamandla kwakunye nexesha elininzi.   I-one-time pad ibalulekile kuba, ukuba isetyenziswa ngendlela eyiyo, ayinakuqhekeka. Mithathu imigaqo emayilandelwe: 
* Isitshixo esiyimfihlo (i-password) masibe side kanye oku komyalezo oyimfihlo; ukuba umyalezo unoonobumba abanama-20, nesitshixo masibe noonobumba abangama-20 ubuncinane.  
* Isitshixo esiyimfihlo masingenziwa ngesicwangciso (umz. KQBWLDA...)
* Isitshixo esiyimfihlelo masisetyenziswe kube kanye kuphela.  Xa kuthunyelwa imiyalezo emibini nangaphezulu, makusetyenziswe izitshixo ezahlukeneyo kumyalezo ngamnye.  
Ukuba le mithetho mithathu iyathotyelwa, kuyakubanzima ukufunda imiyalezo eyimfihlelo xa ungasazi isitshixo esiyimfihlelo. Ngenxa yesi sizathu, ngexesha lemfazwe ye-Cold War, iindawo zoonozakuzaku nezemikhosi emikhulu zazisoloko zisebenzisa i-one-time pads ukuze ziqhagamshelane ekhusini incoko phakathi kwabo kunye noorhulumente ingabinakunqakula bani.   Babeneencwana zabo (pads) ezazizaliswe ziileta ezazizifikela nje ngaphandle kokucwangciswa kwazo nangaphandle kwesicwangciso sokuba makufike zibengaphi na.  Ikhasi ngalinye kwezi ncwadana lalinokusetyenziswa kube kanye kuphela: Yhiyo le nto ibizwa ngokuba yi-"one-time pad".

## I-Encryption kwi-Intanethi
I-Encryption ihlala isetyenziswa kwi-Intanethi, njengoko ii-web sites ezininzi ziyisebenzisa ukukhusela nawuphi na umgosi oyimfihlo. Kwi-Intanethi, ziliqela ii-protocols ze-encryption ezisetyenziswayo, ezifana ne-Secure Sockets Layer (SSL), i-IPsec, kunye ne-SSH. Zisebenzisa inkqubo ye-RSA encryption system kunye nezinye. I-protocol ye-web browsing ekhuselweyo ibizwa ngokuba yi-HTTPS.
I-URL encryption isebenzisa i-MD5 Algorithm ubukhulu becala. Iintlobo-ntlobo ze-algorithms zisetyenziswa kwimakethe ye-intanethi, kuxhomekeke ekubeni zifunwa kangakanani na.  

## Amaphepha anxulumene nala
* FreeOTFE - Disk encryption
* Pretty Good Privacy (PGP) - Email encryption
* PuTTY - SSH encryption