Ukunyandla
Kumchazanyandla, Unyandla noma ukunyandla inqubo yokuguqukezela (encoding) ukwaziswa. Lenqubo iphendula ukuloba okuyindabuko kokwaziswa, okwaziwa ngokuthi isiqakaqo esicacile (plaintext), ikuphendule kube isiqakaqo esiguqukezelwe (ciphertext). Ngokwemfuneko, yilabo abagunyaziwe kuphela abangakwazi ukusithalula (decipher) isiqakaqo esiguqukezelwe sibe isiqakaqo esicacile futhi ukuze bafikelele ekwazisweni okuyindabuko. Ukunyandla ngokwakho akukuvinbeli ukukhubezwa kodwa kulandula lowo ofuna ukweqela isiqikili esiqondekayo.
Ngokwezizathu zobuchule, ukhwatha lokunyandla luvame ukusebenzisa isihluthulelo sonyandla sesithukakalanyali (pseudo-random) esiphehlwa umkholezima. Kuyinto engenzeka ukunyandlulula umyalezo ngaphandle kwesihluthulelo, kodwa okhwatheni lonyandla oluklanywe kahle, kuzodingeka amakhono nezinsiza zomcikizo. Umphiwa ogunyaziwe angawunyandlulula kalula umyalezo ngesihluthulelo asihlinzekwe umsunguli kubaphiwa abagunyaziwe kuphela.
Ngokomlando, izinhlobonhlobo ezingafani zokunyandla ziye zasetshenziswa ukusiza kumchazanyandla. Ubunyoninco bokunyandla bangaohambili babusetshenziswa ekuthumeleni imiyalezo empini. Kusuka lapho, sekuvele ubunyoninco obusha osebusetshenziswa ndawo zonke ekucikizeni kwanamuhla. Ukhwatha lokunyandla lwanamuhla lusebenzisa izicabango zesihluthulelo-somphakathi ngesihluthulelo esifanayo. Ubunyoninco bokunyandla banamuhla buqinisekisa ukuvikela ngokuba iziCikizi zanamuhla ziyehluleka ukugegema unyandla.