rsa.rar_rsa_visual c

#include <stdio.h> int candp(int a,int b,int c) { int r=1; b=b+1; while(b!=1) { r=r*a; r=r%c; b--; } printf("%d\n",r); return r; } void main() { int p,q,e,d,m,n,t,c,r; char s; printf("please input the p,q: "); scanf("%d%d",&p,&q); n=p*q; printf("the n is %3d\n",n); t=(p-1)*(q-1); printf("the t is %3d\n",t); printf("please input the e: "); scanf("%d",&e); if(e<1||e>t) { printf("e is error,please input again: "); scanf("%d",&e); } d=1; while(((e*d)%t)!=1) d++; printf("then caculate out that the d is %d\n",d); printf("the cipher please input 1\n"); printf("the plain please input 2\n"); scanf("%d",&r); switch(r) { case 1: printf("input the m: "); /*输入要加密的明文数字*/ scanf("%d",&m); c=candp(m,e,n); printf("the cipher is %d\n",c);break; case 2: printf("input the c: "); /*输入要解密的密文数字*/ scanf("%d",&c); m=candp(c,d,n); printf("the cipher is %d\n",m);break; } getch(); }