破解php-screw加密过的文件有效方法

今天终于搞定更改过密钥的php-screw解密问题,乐呵一下!

改进下

这样就可以解密任何加密过的PHP源码(包括更改过密钥的),解密的原理稍后具体列出,先说下如何加密

列出之前写使用php screw加密PHP的自动加密代码

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#include <stdio.h> #include <stdlib.h> #include <stdarg.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include "php_screw.h" #include "my_screw.h"   main(int argc, char**argv) {     FILE    *fp;     struct  stat    stat_buf;     char    *datap, *newdatap;     int datalen, newdatalen;     int cryptkey_len = sizeof pm9screw_mycryptkey / 2;     char    newfilename[256];     int i;       if (argc != 2) {         fprintf(stderr, "Usage: filename. ");         exit(0);     }       fp = fopen(argv[1], "r");     if (fp == NULL) {         fprintf(stderr, "File not found(%s) ", argv[1]);         exit(0);     }       fstat(fileno(fp), &stat_buf);     datalen = stat_buf.st_size;     datap = (char*)malloc(datalen + PM9SCREW_LEN);     fread(datap, datalen, 1, fp);     fclose(fp);       if (memcmp(datap, PM9SCREW, PM9SCREW_LEN) == 0) {         fprintf(stderr, "Already Crypted(%s) ", argv[1]);         exit(0);     }       sprintf(newfilename, "%s.screw", argv[1]);       fp = fopen(newfilename, "w");     if (fp == NULL) {         fprintf(stderr, "Can not create file(%s) ", newfilename);         exit(0);     }       newdatap = zencode(datap, datalen, &newdatalen);       for(i=0; i<newdatalen; i++) {         newdatap[i] = (char)pm9screw_mycryptkey[(newdatalen - i) % cryptkey_len] ^ (~(newdatap[i]));     }       fwrite(PM9SCREW, PM9SCREW_LEN, 1, fp);     fwrite(newdatap, newdatalen, 1, fp);     fclose(fp);     fprintf(stderr, "Success Crypting(%s) ", argv[1]);     free(newdatap);     free(datap); }