RSA Algorithm using C

RSA Algorithm using C Language

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#include
#include

int phi,m,n,e,d,c,flag;
int check()
{
int i;
for(i=3;e%i==0&φ%i==0;i+2)
{
flag=1;
return;
}
flag=0;
}


int encrypt()
{
   int i;
  c=1;
   for(i=0;i
   c=c*m%n;
     c=c%n;
   printf("\n\t Encrypted keyword is %d",c);
   return c;
}

void decrypt()
{

   int i;
   m=1;
   for(i=0;i
    m=m*c%n;
   m=m%n;
   printf("\n\t decrypted keyword is %d",m);
}
void main()
{
   int p,q,s;
   clrscr();
   printf("enter two relatively prime numbers");
scanf("%d%d",&p,&q);
   n=p*q;
  phi=(p-1)*(q-1);
  printf("\n\t f(n)\t=%d",phi);
   do
   {
   printf("\n\n Enter e\t");
     scanf("%d",&e);
     check();
  }while(flag==1);
   d=1;
  do
   {
   s=(d*e)%phi;
     d++;
   }while(s!=1);
   d=d-1;
  printf("\n\t Public key{ %d,%d}",e,n);
printf("\n\t Private key{%d,%d}",d,n);
  printf("\n\n Enter the plain text\t");
  scanf("%d",&m);
  encrypt();
  decrypt(c);
   getch();
}

OUTPUT