Vazirligi mirzo ulug„bek nomidagi

Shifrlash.

1. 
   n ni hisoblab olamiz n=q·p=19·43=817
   
2. 
   Matnni 10 lik sanoq sistemasida ifodalaymiz: O → 4F → 79, L → 4C → 76, T → 54 → 84, I → 49 → 73.
   

M=79, 76, 84, 73.

i
2. C_i = M²mod n formula yordamida shifrlash amalga oshiriladi:

1
C₁ = M²mod n = 79²mod 817 = 522,

2

3

4
C₂ = M²mod n = 76²mod 817 = 57, C₃ = M²mod n = 84²mod 817 = 520, C₄ = M²mod n = 73²mod 817 = 427.
C = ^{C₁, C₂, C₃, C₄^} = ^{522,57,520,427^} shifrtekst hosil bo‗ldi.

Shifrni ochish.

Shifrni ochish jarayoniga ko‗proq vaqt sarflanadi. Shifrtekstdagi har bir son alohida ochiladi. C = C₁ = 522 ni ko‗rib chiqamiz.
p +1

1. 
   m₁ = C ⁴ mod p=522¹¹ mod 43=36
   

p +1

2. 
   m ₂ =(p-C ⁴ )mod p =(43-36) mod 43=7
   

q+1
5

3. 
   m ₃ =C ⁴ mod q=522 mod 19=16
   

q+1

4. 
   m ₄ =(q-C ⁴ ) mod q=(19-16) mod 19=3
   
5. 
   a va b larni hisoblash uchun p, q larning teskarisini topib olamiz:
   

p ⁻¹ modq=43^-1mod 19= 5¹⁷ mod 19=4
q ⁻¹ modp=19^-1 mod 43=19⁴¹ mod 43=34

6. 
   a=p(p ⁻¹ mod q)=43·4=172 b=q(q ⁻¹ mod p)=19·34=646
   
7. 
   M₁ =(a·m ₃ +b·m₁ ) mod n=(172·16+646·36) mod 817=681
   
8. 
   M ₂ =(a·m ₄ +b·m₁ ) mod n=(172·3+646·36) mod 817=79
   
9. 
   M ₃ =(a·m ₃ +b·m ₂ ) mod n=(172·16+646·7) mod 817=738
   
10. 
    M ₄ =(a·m ₄ +b·m ₂ ) mod n=(172·3+646·7) mod 817=136
    

Olingan M₁, M₂, M_3, M₄ lardan 127 dan kichiklarini o‗n oltilik sanoq tizimiga o‗tkazamiz: 79₁₀=>4F₁₆=>O harfi paydo bo‗ldi.
1-10 qadamlar C₂, C₃, C₄ larning har biri uchun alohida hisoblanadi.
Shu orqali bizda M=OLTI ochiq matn hosil bo‗ladi.

Mustaqil ish uchun misollar.

1. 
   n=989, C={ 400, 805, 955, 239 }, M=?
   
2. 
   n=989, C={ 307, 831, 133, 384 }, M=?
   
3. 
   n=989, C={ 269, 150, 668, 9 }, M=?
   
4. 
   n=989, C={ 668, 384, 984, 269 }, M=?
   
5. 
   n=989, C={ 680, 302, 400, 269 }, M=?
   
6. 
   n=989, C={ 400, 269, 680, 302 }, M=?
   
7. 
   n=989, C={ 627, 307, 790, 384 }, M=?
   
8. 
   n=989, C={ 790, 307, 984, 269 }, M=?
   
9. 
   n=989, C={ 831, 384, 307, 150 }, M=?
   
10. 
    n=989, C={ 944, 307, 790, 133 }, M=?
    
11. 
    n=989, C={ 96, 307, 955, 133 }, M=?
    
12. 
    n=989, C={ 955, 307, 790, 133 }, M=?
    
13. 
    n=989, C={ 302, 805, 944, 269 }, M=?
    
14. 
    n=989, C={ 96, 307, 831, 944 }, M=?
    
15. 
    n=989, C={ 668, 307, 821, 269 }, M=?
    
16. 
    n=989, C={ 831, 384, 984, 269 }, M=?
    
17. 
    n=989, C={ 133, 384, 790, 805 }, M=?
    
18. 
    n=989, C={ 955, 239, 805, 790 }, M=?
    
19. 
    n=989, C={ 955, 269, 668, 307 }, M=?
    
20. 
    n=989, C={ 680, 307, 831, 269 }, M=?
    
21. 
    n=989, C={ 269, 831, 384, 9 }, M=?
    
22. 
    n=989, C={ 473, 269, 831, 384 }, M=?
    
23. 
    n=437, C={ 119, 232, 308, 115, 95, 85, 187, 87}, M=?
    
24. 
    n=437, C={ 282, 232, 142, 115, 150, 423, 323, 150, 232, 87, 150}, M=?
    
25. 
    n=437, C={ 334, 187, 323, 85, 302, 302, 95, 85, 187, 87}, M=?
    
26. 
    n=437, C={ 282, 232, 121, 150, 254, 85, 177, 301}, M=?
    
27. 
    n=437, C={ 254, 150, 302, 150, 346, 150, 377, 85, 82, 150}, M=?
    
28. 
    n=437, C={ 334, 328, 100, 353, 346, 391, 301, 386}, M=?
    
29. 
    n=437, C={ 119, 346, 323, 302, 292, 302, 346, 254, 150, 302}, M=?
    
30. 
    n=437, C={ 282, 323, 100, 301, 346, 391, 115, 187}, M=?
    
31. 
    n=437, C={ 140, 100, 301, 386, 85, 177, 115, 248, 150}, M=?
    
32. 
    n=437, C={ 64, 232, 427, 334, 187, 323, 150, 150, 301}, M=?
    
33. 
    N=989, C={307,785,311}; N=209, C={130,4,163,157,80,4,163,
    

199,38}; N=473, C={170,232}, M=?

34. 
    N=209, C={36,169,4,169}; N=253, C={110,48,133,93,133}; N=817, C={815,404}, M=?
    
35. 
    N=473, C={102,23,56,422}; N=253, C={9,69}; N=817, C={427,
    

662,384,397,741}, M=?

36. 
    N=209, C={133,199,58}; N=473, C={441,275,203,268,312,
    

268,454}; N=817, C={139,422,226}, M=?

37. 
    N=253, C={55,48,93,69,81}; N=817, C={226,66,662,422}; N=473, C={170,232}. M=?
    
38. 
    N=817, C={140,404};N=253, C={110,146,26,48,209}; N=209, C={158,157,187,187,169,38}, M=?
    
39. 
    N=817, C={723,741,617,178,397,752,741,66}; N=253, C={210,
    

146,177,209}. M=?

40. 
    N=473, C={99,268,275,471,146,97,422}; N=817, C={681,66,
    

741,384,66}, M=?

6.