029_Enc.c File Reference

#include <stdio.h>

Include dependency graph for 029_Enc.c:

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Macros
#define	MC   2048

Functions
int	main (int argc, char *argv[])

Macro Definition Documentation

MC

#define MC   2048

Definition at line 3 of file 029_Enc.c.

Function Documentation

main()

int main	(	int	argc,
		char *	argv[] )

Definition at line 5 of file 029_Enc.c.

{
    char str[MC], strE[MC], strD[MC], aux[MC];
    int i, nc, a, ai, b, n;
    a = 17;
//  ai = 49;
    b = 21;
    n = 52;
    i=0;
    do{
        str[i++] = getc(stdin);
    }while(str[i-1]!=10);
    str[i-1] = '\0';
    nc = i-1;
    printf("MSG: %s\n", str);
    for(i=0; i<nc; i++)
        printf("%d ", str[i]);
    printf("\n");
    for(i=0; i<nc; i++)
    {
        aux[i] = str[i]-'A'-6*(str[i]>='a');
        printf("%d ", aux[i]);
    }
    printf("\n");
    for(i=0; i<nc; i++)
    {
        aux[i] = (a*((int)aux[i])+b)%n;
        printf("%d ", aux[i]);
    }
    printf("\n");
    for(i=0; i<nc; i++)
        strE[i] = aux[i]+'A'+6*(aux[i]>(n/2-1));
    strE[nc]='\0';
    printf("%s\n", strE);
    for(i=0; i<nc; i++)
    {
        aux[i] = strE[i]-'A'-6*(strE[i]>='a');
        printf("%d ", aux[i]);
    }
    printf("\n");
    ai=1;
    while(((ai*a)%n)!=1)
        ai++;
    printf("ai = %d\n", ai);
    for(i=0; i<nc; i++)
    {
        aux[i] = (ai*((aux[i]<b)*n+aux[i]-b))%n;
        printf("%d ", aux[i]);
    }
    printf("\n");
    for(i=0; i<nc; i++)
    {
        strD[i] = aux[i]+'A'+6*(aux[i]>25);
        printf("%d ", strD[i]);
    }
    strD[nc] = '\0';
    printf("\n");
    printf("%s\n", strD);
    return 0;
}