Bajardi: Akramov Farhod Tekshirdi: Axmedova Nozima

Muhammad Al-Xorazmiy nomidagi

Toshkent Axborot Texnologiyalari Universiteti.

AMALIY ISHI

Mavzu:  Kriptografik himoyalash.

Guruh: 314-19

Bajardi: Akramov Farhod Tekshirdi: Axmedova Nozima

2-amaliy ish

Kriptografik himoyalash

AKRAMOV_FARHOD so’zini turli usullarda shifrlash

1.Sezar usuli

Sezar shifrlash usuli bu belgini ma’lum bir qoununiyat asosida siljitish orqali shifrlash usuli hisoblanadi.Bu usulni Rim imperatori Yuliy Sezar kashf etgan.Bu usulda shifrlanayotgan harflar k ga siljitib almashtiriladi. Bu yerda M – butun son hisoblanib , ochiq matn belgisin alfavitdagi o’rni , C- butun son bo’lib , shifr belgini alfavitdagi o’rni . C=(M+k) mod m , m bu yerda alfavit uzunligi. Deshifrlash uchun esa M=(C-k) mod m ifodadan foydalaniladi. Sezar shifrlash usulida k=3 deb foydalanilgan.

L otin alfaviti uchun:

T₀= AKRAMOV k=3

Shifrlangan matn: T₁=DNUPRY

2. O’rin almashtirish usuli

A	M	F	O
K	O	A	D
R	V	R	-
A	-	H	-

T₀=Akramov Farhod

Shifrlangan matn: T₁=AMFOKOADRVR-A-H-

3. Vernam usuli

T₀=AKRAMOVFARHOD K=QAYCHI

• 
  A=0=00000 N=13=01101 #=26=11010
  
• 
  B=1=00001 O=14=01110 !=27=11011
  
• 
  C=2=00010 P=15=01111 _=28=11100
  
• 
  D=3=00011 Q=16=10000 @=29=11101
  
• 
  E=4=00100 R=17=10001 ?=30=11110
  
• 
  F=5=00101 S=18=10010 *=31=11111
  
• 
  G=6=00110 T=19=10011
  
• 
  H=7=00111 U=20=10100
  
• 
  I=8=01000 V=21=10101
  
• 
  J=9=01001 W=22=10110
  
• 
  K=10=01010 X=23=10111
  
• 
  L=11=01011 Y=24=11000
  
• 
  M=12=01100 Z=25=11001
  

A + Q = 00000 + 10000= 10000= Q

K + A = 01010+00000 = K

R + Y = 10001+11000= V

A+ C = 00000 + 00010= 00010= C

M + H = 01100+ 00111=1 0011‬= T

O + I = 01110+ 01000= O

V + Q = 10101+10000= 10011 = T

F + A = 00101+ 00000 = 00101 = F

A + Y = 11000= Y

R + C = 10001+ 00010= 1 0011= T

H + H = 00111+ 00111= 1110 = L

O + I= 01110+01000=1 0110‬=W

D + Q= 1 0011= T

Shifrlangan matn: T₁=QKVCTOTFYTLWT