client.c

一个用c语言编写的加密算法。希望大家喜欢

#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <string.h>

#define PORT         5656
#define MAXDATASIZE  100


int encrypt(char** charb,int size)
{

	int i;
	char *buf;

	buf = (char*)(malloc(size+1));
	buf = charb;
	for(i=0;i<size;i++)
	{

		buf[i] = *(buf+i)+1;

	}
	charb = buf;
	buf=NULL;
	return 0;
}




int main(int argc,char * argv[])
{
	int 	fd,numbytes;
	int 	charLen;
	char     charBuf[MAXDATASIZE];
	char 	buf[MAXDATASIZE];
	struct hostent * 	he;
	struct sockaddr_in  server;
	if(argc!=2)
	{
		printf("Usage: %s <IP address>\n",argv[0]);
		exit(-1);
	}

	if((he=gethostbyname(argv[1]))==NULL)
	{
		perror("Gethostbyname error!");
		exit(1);
	}

	if((fd=socket(AF_INET,SOCK_STREAM,0))==-1)
	{
		perror("Create socket failed!");
		exit(1);
	}

	bzero(&server,sizeof(server));
	server.sin_family=AF_INET;
	server.sin_port=htons(PORT);
	server.sin_addr=(*((struct in_addr *)he->h_addr));        /*ȡֵ*/

	if(connect(fd,(struct sockaddr *)&server,sizeof(struct sockaddr))==-1)
	{
		perror("Connct failed!");
		exit(1);
	}

	if((numbytes=recv(fd,buf,MAXDATASIZE,0))==-1)
	{
		perror("Recv error!");
		exit(1);
	}

	buf[numbytes]='\0';
	printf("Server Message: %s >>",buf);
	scanf("%s",charBuf);
	charLen=strlen(charBuf);
	encrypt(&charBuf,charLen);
	printf("You send characters is : %s\n",charBuf);
	send(fd,charBuf,charLen,0);
	if((numbytes=recv(fd,buf,MAXDATASIZE,0))==-1)
	{
		perror("Recv error!");
		exit(1);
	}
	buf[numbytes]='\0';
	printf("Received Characters is : %s \n",buf);
	close(fd);
	return 0;
}