文件加密解密小程序

#include <stdio.h>#include <stdlib.h>#include <string.h>int process(char *filename, char *opration);int read_file(char *filename, char **buf);int write_file(char *buf, long file_size);int decode(char *buf, int file_size, int key);int encrypt(char *buf, int file_size, int key);int main(int argc, char **argv){char flag;if (argc != 3) {printf("error!the type is :%s <filename> <opration>\n", argv[0]);exit(-1); }if ((*argv[2] == 'e') || (*argv[2] == 'd'))  process(argv[1], argv[2]);else {printf("error:opration only be e(encrypt) or d(decode)\n");exit(-1); }return 0;}int process(char *filename, char *opration){FILE *myfile_dst;char *buf;int key = 123;long file_size;file_size = read_file(filename, &buf);if (*opration == 'e')  encrypt(buf, file_size, key);else if(*opration == 'd')   decode(buf, file_size, key);write_file(buf, file_size);return 0;}int read_file(char *filename, char **buf){FILE *myfile_src;long file_size;if (!(myfile_src = fopen(filename, "r"))) {perror("fopen"); }fseek(myfile_src, 0, SEEK_END);file_size = ftell(myfile_src);fseek(myfile_src, 0, SEEK_SET);*buf = (char *)malloc(file_size);fread(*buf, 1, file_size, myfile_src);fclose(myfile_src);return file_size;}int write_file(char *buf, long file_size){FILE *myfile_dst;char filename[20];printf("please input the file name that you want to save:\n");scanf("%s", filename);if (!(myfile_dst = fopen(filename, "wb"))) {perror("fopen"); }fwrite(buf, 1, file_size, myfile_dst);printf(">>>>>>>>>>>>>>%s is save<<<<<<<<<<<<<<<\n", filename);fclose(myfile_dst);return 0;}int encrypt(char buf[], int file_size, int key){int i;for(i = 0; i < file_size; i ++)  buf[i] = buf[i] + key;return 0;}int decode(char *buf, int file_size, int key){int i;for(i = 0; i < file_size; i ++)  buf[i] = buf[i] - key;return 0;}

非常简单的文件加密解密，有很多缺陷需要修改，以后慢慢增加