Kriptotizimlarning ikkita sinfi farklanadi

Shifrlash: shifrlash quyidagi formula yordamida amalga oshiriladi. Bunda harflar o’rniga gammalash jadvalidagi o’nlik sonlarqo’yiladi.
U^e mod n=21²⁷⁷ mod 54707=45805
S^e mod n=18²⁷⁷ mod 54707=31014
M^e mod n=14²⁷⁷ mod 54707=33510
O^e mod n=16²⁷⁷ mod 54707=45805
N^e mod n=15²⁷⁷ mod 54707=51224
O^e mod n= 16²⁷⁷ mod 54707=4243
V^e mod n=22²⁷⁷ mod 54707=39974
S^e mod n=18²⁷⁷ mod 54707=3964
H^e mod n=9²⁷⁷ mod 54707=49193
A^e mod n=1²⁷⁷ mod 54707=1
X^e mod 24=9²⁷⁷ mod 54707=4243
O^e mod n=16²⁷⁷ mod 54707=31014
B^e mod n=2²⁷⁷ mod 54707=3964
T₁=45805,31014,33510,45805,51224,4243,39974,3964,49193,1,4243,31014,3964
Shifrlangan matn ko’rinishi .

2-rasm. RSA shifrlash algoritmida shifrlash va deshifrlash jarayoni
Deshifrlash: Deshifrlash jarayonida shifrlangan matnni yopiq kalit yordamida shifrlaymiz.
T₁=45805,31014,33510,45805,51224,4243,39974,3964,49193,1,4243,31014,3964
45805^d mod n=45805³¹³³ mod 54707=21=U
31014^d mod n=31014³¹³³ mod 54707=18=S
33510^d mod n=33510³¹³³ mod 54707=14=M
45805^d mod n=45805³¹³³ mod 54707=15=O
51224^d mod n=51224³¹³³ mod 54707=16=N
4243^d mod n=4243³¹³³ mod 54707=15=O
39974^d mod n=39974³¹³³ mod 54707=22=V
3964^d mod n=3964³¹³³ mod 54707=18=S
49193^d mod n=49193³¹³³ mod 54707=9=H
45805^d mod n=1³¹³³ mod 54707=1=A
4243^d mod n=4243³¹³³ mod 54707=24=X
31014^d mod n=31014³¹³³ mod 54707=15=O
3964^d mod n=3964³¹³³ mod 54707=2=B
T₀= USMONOVSHAXOB
DES shifrlash algoritmi. DES shifrlash algoritmi AQShda 1998 yilning 31 dekabrgacha standart shifrlash algoritmi deb hisoblangan. Bu algoritmda qo'llanilgan akslantirishlar kriptografik nuqtai nazardan bardoshli, ammo dastlabki 56 - bitli kalitning uzunligi, bugungi kun hisoblash texnika va texnologiyalarining yutuqlaridan foydalanilganda, mumkin bo'lgan barcha 256 ta kalitlarni to'la tanlab chiqish imkoniyatini sezilarli qisqartiradi.
AQShning “Standartlar va Texnologiyalar Milliy Instituti” tomonidan 1997 yilda yangi standart uchun konkurs e'lon qilinib, 2000 yilning 2 oktyabrida uning g'olibi aniqlandi. Bu standart shifrlash algoritmi AES FIPS -197 deb nomlanib, uning asosini Feystel tarmog'i tashkil etmaydi.

3-rasm. DES shifrlash algoritmida shifrlash jarayoni