#include <stdio.h>
#include <stdlib.h>
unsigned long prime1,prime2,ee
unsigned long *kzojld(unsigned long p,unsigned long q) //扩展欧几里得算法求模逆
{
unsigned long i=0,a=1,b=0,c=0,d=1,temp,mid,ni[2]
mid=p
while(mid!=1)
{
while(p>q)
{p=p-q mid=pi++}
a=c*(-1)*i+ab=d*(-1)*i+b
temp=aa=cc=temp
temp=bb=dd=temp
temp=pp=qq=temp
i=0
}
ni[0]=cni[1]=d
return(ni)
}
unsigned long momi(unsigned long a,unsigned long b,unsigned long p) //模幂算法
{
unsigned long c
c=1
if(a>p) a=a%p
if(b>p) b=b%(p-1)
while(b!=0)
{
while(b%2==0)
{
b=b/2
a=(a*a)%p
}
b=b-1
c=(a*c)%p
}
return(c)
}
void RSAjiami() //RSA加密函数
{
unsigned long c1,c2
unsigned long m,n,c
n=prime1*prime2
system("cls")
printf("Please input the message：\n")
scanf("%lu",&m)getchar()
c=momi(m,ee,n)
printf("The cipher is：%lu",c)
return
}
void RSAjiemi() //RSA解密函数
{
unsigned long m1,m2,e,d,*ni
unsigned long c,n,m,o
o=(prime1-1)*(prime2-1)
n=prime1*prime2
system("cls")
printf("Please input the cipher：\n")
scanf("%lu",&c)getchar()
ni=kzojld(ee,o)
d=ni[0]
m=momi(c,d,n)
printf("The original message is：%lu",m)
return
}
void main()
{ unsigned long m
char cho
printf("Please input the two prime you want to use:\n")
printf("P=")scanf("%lu",&prime1)getchar()
printf("Q=")scanf("%lu",&prime2)getchar()
printf("E=")scanf("%lu",&ee)getchar()
if(prime1<prime2)
{m=prime1prime1=prime2prime2=m}
while(1)
{
system("cls")
printf("\t*******RSA密码系统*******\n")
printf("Please select what do you want to do:\n")
printf("1.Encrpt.\n")
printf("2.Decrpt.\n")
printf("3.Exit.\n")
printf("Your choice:")
scanf("%c",&cho)getchar()
switch(cho)
{ case '1':RSAjiami()break
case '2':RSAjiemi()break
case '3':exit(0)
default:printf("Error input.\n")break
}
getchar()
}
}
* RSA.H - header file for RSA.C*/
/* Copyright (C) RSA Laboratories, a division of RSA Data Security,
Inc., created 1991. All rights reserved.
*/
int RSAPublicEncrypt PROTO_LIST
((unsigned char *, unsigned int *, unsigned char *, unsigned int,
R_RSA_PUBLIC_KEY *, R_RANDOM_STRUCT *))
int RSAPrivateEncrypt PROTO_LIST
((unsigned char *, unsigned int *, unsigned char *, unsigned int,
R_RSA_PRIVATE_KEY *))
int RSAPublicDecrypt PROTO_LIST
((unsigned char *, unsigned int *, unsigned char *, unsigned int,
R_RSA_PUBLIC_KEY *))
int RSAPrivateDecrypt PROTO_LIST
((unsigned char *, unsigned int *, unsigned char *, unsigned int,
R_RSA_PRIVATE_KEY *))
