C语言之文件的加密与解密
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#include<stdio.h> #include<stdlib.h> int getfilesize(char *path) { FILE *pf = fopen(path, "r"); if (pf == NULL) { return -1; } else { fseek(pf, 0, SEEK_END); int length = ftell(pf); return length; } } /* void copy(char *oldpath, char *newpath) { FILE *pfr, *pfw; pfr = fopen(oldpath, "rb"); pfw = fopen(newpath, "wb"); if (pfr == NULL || pfw == NULL) { fclose(pfr); fclose(pfw); return; } else { int length = getfilesize(oldpath); char *p = (char *)malloc(length*sizeof(char)); fread(p, sizeof(char), length, pfr); fwrite(p, sizeof(char), length, pfw); fclose(pfr); fclose(pfw); } } */ void EncryptFile(char *oldpath, char *newpath) { int i = 0; FILE *pfr, *pfw; pfr = fopen(oldpath, "rb"); pfw = fopen(newpath, "wb"); if (pfr == NULL || pfw == NULL) { fclose(pfr); fclose(pfw); return; } else { int length = getfilesize(oldpath); char *p = (char *)malloc(length*sizeof(char)); fread(p, sizeof(char), length, pfr); for (i = 0; i < length; i++) { p[i] ^= 'A'; } fwrite(p, sizeof(char), length, pfw); fclose(pfr); fclose(pfw); } } void DecryptFile(char *oldpath, char *newpath) { int i = 0; FILE *pfr, *pfw; pfr = fopen(oldpath, "rb"); pfw = fopen(newpath, "wb"); if (pfr == NULL || pfw == NULL) { fclose(pfr); fclose(pfw); return; } else { int length = getfilesize(oldpath); char *p = (char *)malloc(length*sizeof(char)); fread(p, sizeof(char), length, pfr); for (i = 0; i < length; i++) { p[i] ^= 'A'; } fwrite(p, sizeof(char), length, pfw); fclose(pfr); fclose(pfw); } } void main() { char *oldpath = "tmAppAbDBB.db"; char *newpath = "aa.db"; char *newDecryptFilepath = "cc.db"; EncryptFile(oldpath, newpath); DecryptFile(newpath, newDecryptFilepath); }