unsigned int pad text ( char padded, char unpadded ) 2 unsigned int len 0 3 unsigned int ptr 0 4 5 Get string length 6 while ( unpadded len ) 7 8 Get padding amount 9 unsigned int npadding ( 4 ( len 4 ) ) 4 1 0 1 1 Copy the original string 1 2 do 1 3 padded ptr unpadded ptr 1 4 while ( unpadded ptr unpadded ptr ) 1 5 1 6 Padding 1 7 for ( int i 0 i npadding i ) 1 8 padded ptr i 0 1 9 2 0 2 1 return ( ( len 3 ) 4 ) 2 2 unsigned int sdes gen key ( char pw ) 2 unsigned int k 0 3 char c 0 4 5 while ( pw pw ) 6 char c pw 7 k k c 8 k ( ( k 0 xFF ) 2 4 ) ( k 8 ) 9 k k c 1 0 1 1 1 2 return k 1 3 unsigned int sdes perm ( unsigned int d ) 2 3 unsigned int r d 4 5 r ( ( r 0 xFFFF 0 0 0 0 llu ) 1 6 ) ( ( r 0 x 0 0 0 0 FFFFllu ) 1 6 ) 6 r ( ( r 0 xFF 0 0 FF 0 0 llu ) 8 ) ( ( r 0 x 0 0 FF 0 0 FFllu ) 8 ) 7 r ( ( r 0 xF 0 F 0 F 0 F 0 llu ) 4 ) ( ( r 0 x 0 F 0 F 0 F 0 Fllu ) 4 ) 8 r ( ( r 0 xCCCCCCCCllu ) 2 ) ( ( r 0 x 3 3 3 3 3 3 3 3 llu ) 2 ) 9 r ( ( r 0 xAAAAAAAAllu ) 1 ) ( ( r 0 x 5 5 5 5 5 5 5 5 llu ) 1 ) 1 0 1 1 return r 1 2 unsigned int sdes gen roundkey ( unsigned int i , unsigned k ) 2 Just a Simple Rotation 3 unsigned int nbits ( i 8 ) 4 4 5 unsigned mask ( 1 llu nbits ) 1 6 unsigned res ( ( k mask ) ( 3 2 nbits ) ) ( k nbits ) 7 8 return res 9 void sdes encrypt ( char clear, char cipher, unsigned int key, unsigned int nblocks ) 2 unsigned int clear ( unsigned int ) clear 3 unsigned int cipher ( unsigned int ) cipher 4 5 for ( int i 0 i nblocks i ) 6 Get a block from the string 7 unsigned int block clear i 8 9 Encrypt 1 0 unsigned int cipher i sdes encrypt block ( block , key ) 1 1 cipher i e block 1 2 1 3 unsigned int sdes encrypt block ( unsigned int x , unsigned int key ) 2 unsigned int d 0 3 4 d sdes perm ( x ) 5 for ( int i 0 i 8 i ) 6 unsigned int roundkey sdes gen roundkey ( i , key ) 7 d sdes encrypt round ( i , d , roundkey ) 8 9 d sdes perm ( d ) 1 0 1 1 r unsigned int sdes encrypt round ( unsigned int i , unsigned int block, unsigned int rkey ) 2 unsigned int cipher 0 3 4 cipher b 5 cipher cipher rkey XOR 6 cipher sdes encrypt sbox ( i , cipher ) Substitution 7 8 return cipher 9 TheS boxesaresimplelook uptables 1 char sbox 1 6 2 , 1 2 , 4 , 1 , 7 , 1 0 , 1 1 , 6 , 8 , 5 , 3 , 1 5 , 1 3 , 0 , 1 4 , 9 , 2 1 4 , 1 1 , 2 , 1 2 , 4 , 7 , 1 3 , 1 , 5 , 0 , 1 5 , 1 0 , 3 , 9 , 8 , 6 , 3 4 , 2 , 1 , 1 1 , 1 0 , 1 3 , 7 , 8 , 1 5 , 9 , 1 2 , 5 , 6 , 3 , 0 , 1 4 , 4 1 1 , 8 , 1 2 , 7 , 1 , 1 4 , 2 , 1 3 , 6 , 1 5 , 0 , 9 , 1 0 , 4 , 5 , 3 5 6 unsigned int sdes encrypt sbox ( unsigned int i , unsigned int block ) 7 unsigned int res 0 8 i i 4 9 1 0 for ( int n 0 n 8 n ) 1 1 char c block 0 xF 1 2 char s sbox i c 1 3 res ( s 2 8 ) ( res 4 ) 1 4 1 5 block block 4 Done with one nibble 1 6 1 7 1 8 return res 1 9 void sdes decrypt ( char cipher, char clear, unsigned int key, unsigned int nblocks ) 2 unsigned int clear ( unsigned int ) clear 3 unsigned int cipher ( unsigned int ) cipher 4 5 for ( int i 0 i nblocks i ) 6 Get a block from the string 7 unsigned int e block cipher i 8 9 Encrypt 1 0 unsigned int block sdes decrypt block ( e block, key ) 1 1 clear i block 1 2 1 3 Then,weimplementafunctiontoimplementS DESdecryptionofoneblock 1 unsigned int sdes decrypt block ( unsigned int x , unsigned int key ) 2 unsigned int d sdes perm ( x ) 3 for ( int i 0 i 8 i ) 4 unsigned int roundkey sdes gen roundkey ( 7 i , key ) 5 d sdes decrypt round ( 7 i , d , roundkey ) 6 7 d sdes perm ( d ) 8 9 return d 1 0 unsigned int sdes decrypt round ( unsigned int i , unsigned int ciph, unsigned int rkey ) 2 unsigned int block 0 3 4 block sdes decrypt sbox ( i , ciph ) Substitution 5 block block rkey XOR

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Question: unsigned int pad _ text ( char * padded, char * unpadded ) { 2 unsigned int len = 0 ; 3 unsigned int ptr

unsigned int pad

_

text

(

char

*

padded, char

*

unpadded

) {2

unsigned int len

= 0

;

3

unsigned int ptr

= 0

;

4 5 / *

Get string length

* / 6

while

(

unpadded

[

len

+ +])

;

7 8 / *

Get padding amount

* / 9

unsigned int npadding

= (4 - (

len

% 4)) % 4

;

10 11 / *

Copy the original string

* / 12

{13

padded

[

ptr

] =

unpadded

[

ptr

]

;

14}

while

(

unpadded

[

ptr

]

&& unpadded

[

ptr

+ +]! =

)

;

15 16 / *

Padding

* / 17

for

(

int i

= 0

; i

<

npadding; i

+ +) {18

padded

[

ptr

+

] = \ 0

;

19} 20 21

return

((

len

+ 3) / 4)

;

22}

unsigned int sdes

_

gen

_

key

(

char

*

) {2

unsigned int k

= 0

;

3

char c

= 0

;

4 5

while

(*

pw &&

*

! =

) {6

char c

= *

+ +

;

7

=

^

8

= ((

k &

0

xFF

) < < 24) | (

> > 8)

;

9

=

+

10} 11 12

return k;

13}

unsigned int sdes

_

perm

(

unsigned int d

) {2 3

unsigned int r

=

4 5

= ((

r &

0

xFFFF

0000

llu

) > > 16) | ((

r &

0

0000

FFFFllu

) < < 16)

;

6

= ((

r &

0

xFF

00

00

llu

) > > 8) | ((

r &

0

00

00

FFllu

) < < 8)

;

7

= ((

r &

0

0

0

0

0

llu

) > > 4) | ((

r &

0

0

0

0

0

Fllu

) < < 4)

;

8

= ((

r &

0

xCCCCCCCCllu

) > > 2) | ((

r &

0

33333333

llu

) < < 2)

;

9

= ((

r &

0

xAAAAAAAAllu

) > > 1) | ((

r &

0

55555555

llu

) < < 1)

;

10 11

return r;

12}

unsigned int sdes

_

gen

_

roundkey

(

unsigned int i

,

unsigned k

) {2 / *

Just a Simple Rotation

* / 3

unsigned int nbits

= (

% 8) * 4

;

4 5

unsigned mask

= (1

llu

< <

nbits

) - 1

;

6

unsigned res

= ((

k & mask

) < < (32 -

nbits

)) | (

> >

nbits

)

;

7 8

return res;

9}

void sdes

_

encrypt

(

char

*_

clear, char

*_

cipher, unsigned int key, unsigned int nblocks

) {2

unsigned int

*

clear

= (

unsigned int

*)_

clear;

3

unsigned int

*

cipher

= (

unsigned int

*)_

cipher;

4 5

for

(

int i

= 0

; i

<

nblocks; i

+ +) {6 / *

Get a block from the string

* / 7

unsigned int block

=

clear

[

]

;

8 9 / *

Encrypt

* / 10

unsigned int cipher

[

] =

sdes

_

encrypt

_

block

(

block

,

key

)

;

11

cipher

[

] =

_

block;

12} 13}

unsigned int sdes

_

encrypt

_

block

(

unsigned int x

,

unsigned int key

) {2

unsigned int d

= 0

;

3 4

=

sdes

_

perm

(

)

;

5

for

(

int i

= 0

; i

< 8

; i

+ +) {6

unsigned int roundkey

=

sdes

_

gen

_

roundkey

(

,

key

)

;

7

=

sdes

_

encrypt

_

round

(

,

,

roundkey

)

;

8} 9

=

sdes

_

perm

(

)

;

10 11

unsigned int sdes

_

encrypt

_

round

(

unsigned int i

,

unsigned int block, unsigned int rkey

) {2

unsigned int cipher

= 0

;

3 4

cipher

=

5

cipher

=

cipher

^

rkey;

/ *

XOR

* / 6

cipher

=

sdes

_

encrypt

_

sbox

(

,

cipher

)

;

/ *

Substitution

* / 7 8

return cipher;

9}

TheS

-

boxesaresimplelook

-

uptables:

1

char sbox

[] [16] = {{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9}, 2 {14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6}, 3 {4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14}, 4 {11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}}

;

5 6

unsigned int sdes

_

encrypt

_

sbox

(

unsigned int i

,

unsigned int block

) {7

unsigned int res

= 0

;

8

=

% 4

;

9 10

for

(

int n

= 0

; n

< 8

; n

+ +) {11

char c

=

block &

0

xF;

12

char s

=

sbox

[

] [

]

;

13

res

= (

< < 28) | (

res

> > 4)

;

14 15

block

=

block

> > 4

;

/ *

Done with one nibble

* / 16} 17 18

return res;

19}

void sdes

_

decrypt

(

char

*_

cipher, char

*_

clear, unsigned int key, unsigned int nblocks

) {2

unsigned int

*

clear

= (

unsigned int

*)_

clear;

3

unsigned int

*

cipher

= (

unsigned int

*)_

cipher;

4 5

for

(

int i

= 0

; i

<

nblocks; i

+ +) {6 / *

Get a block from the string

* / 7

unsigned int e

_

block

=

cipher

[

]

;

8 9 / *

Encrypt

* / 10

unsigned int block

=

sdes

_

decrypt

_

block

(

_

block, key

)

;

11

clear

[

] =

block;

12} 13}

Then,weimplementafunctiontoimplementS

-

DESdecryptionofoneblock:

1

unsigned int sdes

_

decrypt

_

block

(

unsigned int x

,

unsigned int key

) {2

unsigned int d

=

sdes

_

perm

(

)

;

3

for

(

int i

= 0

; i

< 8

; i

+ +) {4

unsigned int roundkey

=

sdes

_

gen

_

roundkey

(7 -

,

key

)

;

5

=

sdes

_

decrypt

_

round

(7 -

,

,

roundkey

)

;

6} 7

=

sdes

_

perm

(

)

;

8 9

return d;

10}

unsigned int sdes

_

decrypt

_

round

(

unsigned int i

,

unsigned int ciph, unsigned int rkey

) {2

unsigned int block

= 0

;

3 4

block

=

sdes

_

decrypt

_

sbox

(

,

ciph

)

;

/ *

Substitution

* / 5

block

=

block

^

rkey;

/ *

XOR

* / Step by Step Solution There are 3 Steps involved in it 1 Expert Approved Answer Step: 1 Unlock Question Has Been Solved by an Expert! Get step-by-step solutions from verified subject matter experts View Solution Step: 2 Unlock Step: 3 UnlockStudents Have Also Explored These Related Programming Questions! Q: Note: Here is the recursive function so that you can copy it. unsigned int distance (const char *a, const char *b) { unsigned int a_len = strlen(a); unsigned int b_len =strlen(b); /* The base case... Q: I have the follwing C code. I need to combine the put() function with the processline() function and put it in the main function. You don't need to worry about what the program does. processline... Q: In C Language. Note: Here is the recursive function so that you can copy it. unsigned int distance (const char *a, const char *b) { unsigned int a_len = strlen(a); unsigned int b_len =strlen(b); /*... Q: Help create the vcipher.h and vcipher.cc files for the vigenere cipher which MUST inherit from substitution and running key cipher(kcipher.h and kcipher.cc). Please follow the instructions and... Q: please write the code in language C using the following instructions, make sure the code runs and compiles on brightspace A review of BIT 1400 Assignment deliverable: You will create structs for... Q: Introduction This assignment reviews what you learned in BIT 1400. Your job (with some hints along the way) is to create a "university registrar" that has all information about students and courses... Q: Complete TODO in ccipher.h and ccipher.cc inheriting from cipher.cc: Substitution cipher (implemented in cipher.h and cipher.cc) class has already been defined (but not implemented) for you. The... Q: Please help me fill out the TODO parts in the Caesar cipher that must follow these requirements: Substitution cipher (implemented in cipher.h and cipher.cc) class has already been defined (but not... Q: Please help write the Caesar cipher. It must follow the these requirements: Substitution cipher (implemented in cipher.h and cipher.cc) class has already been defined (but not implemented) for you.... Q: Help create the kcipher.h and kcipher.cc files for the running key cipher which MUST inherit from substitution. Please follow the instructions and complete the provided code: Substitution cipher... Q: A business might worry that pricing of one product might impact demand for another product that is also sold by the same business. Here well explore conditions under which such worries are more or... Q: Beyond Center has 11,500 common shares outstanding at $49 per share. it also owns 280 preferred shares outstanding at $91 per share. There are 310 bonds with a coupon rate of 6.8 percent that are... Q: 1. What would be the effect of lowering the reactor temperature in the Haber Process? Percentage of ammonia in the equilibrium mixture Time taken for the reaction mixture to reach equilibrium less A... Q: oday the common stock of Gresham Technology closed at $24.1024.10 per share, down $0.360.36 from yesterday. If the company has 3.43.4 million shares outstanding and annual earnings of $8.68.6... Previous Question Next QuestionRecommended Textbook More Books Introduction To Wireless And Mobile Systems Authors: Dharma P. Agrawal, Qing An Zeng 4th Edition 1305087135, 978-1305087132, 9781305259621, 1305259629, 9781305537910, 978-130508713 Ask a Question and Get Instant Help! Get AnswerStudy Help Open in AppServices Sitemap Fun Definitions Become Tutor Used Textbooks Study Help Categories Recent Questions Expert Questions Campus Wear Sell Your Books Company Info Security Copyrights Privacy Policy Terms & Conditions SolutionInn Fee Scholarship Online Quiz Give Feedback, Get Rewards Get In Touch About Us Contact Us Career Jobs FAQ Student Discount Campus Ambassador Secure Payment Download Our App © 2026 SolutionInn. All Rights Reservedwindow.addEventListener("load",function(){jQuery(document).ready(function(t){

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