73 lines
2.2 KiB
C
73 lines
2.2 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <openssl/md5.h>
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#include <openssl/blowfish.h>
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void getKey(char* trackId, char* key) {
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unsigned char digest[MD5_DIGEST_LENGTH];
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MD5_CTX context;
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MD5_Init(&context);
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MD5_Update(&context, trackId, strlen(trackId));
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MD5_Final(digest, &context);
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char MD5String[33];
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for (int i = 0; i < 16; i++)
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sprintf(&MD5String[i*2], "%02x", (unsigned int)digest[i]);
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const char secret[] = "g4el58wc0zvf9na1";
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for(int i=0; i<16; i++)
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key[i] = MD5String[i] ^ MD5String[i+16] ^ secret[i];
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}
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void decryptFile(char* decKey, const char* inputfn, const char* outputfn) {
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unsigned char* bfKey = reinterpret_cast<unsigned char*>(decKey);
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BF_KEY key;
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BF_set_key(&key, 16, bfKey);
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FILE* ofile = fopen(outputfn, "wb");
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FILE* ifile = fopen(inputfn, "rb");
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int i=0;
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while (!feof(ifile)) {
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unsigned char buffer[2048];
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int read = fread(buffer, 1, 2048, ifile);
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if (i % 3 == 0 && read == 2048) {
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unsigned char decrypted[2048];
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unsigned char IV[8] = {0,1,2,3,4,5,6,7};
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BF_cbc_encrypt(buffer, decrypted, 2048, &key, IV, BF_DECRYPT);
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fwrite(decrypted, sizeof(unsigned char), sizeof(decrypted), ofile);
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} else {
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fwrite(buffer, sizeof(unsigned char), read, ofile);
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}
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i++;
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}
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fclose(ofile);
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fclose(ifile);
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}
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void decryptBytes(char* decKey, long length, unsigned char* data, unsigned char* output) {
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unsigned char* bfKey = reinterpret_cast<unsigned char*>(decKey);
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BF_KEY key;
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BF_set_key(&key, 16, bfKey);
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int count = length/2048;
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int i=0;
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for(i=0; i<count; i++) {
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if (i % 3 == 0) {
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unsigned char buffer[2048];
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memcpy(buffer, &data[i*2048], 2048);
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unsigned char decrypted[2048];
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unsigned char IV[8] = {0,1,2,3,4,5,6,7};
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BF_cbc_encrypt(buffer, decrypted, 2048, &key, IV, BF_DECRYPT);
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memcpy(&output[i*2048], decrypted, 2048);
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} else {
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memcpy(&output[i*2048], &data[i*2048], 2048);
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}
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}
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if (length % 2048 != 0){
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memcpy(&output[i*2048], &data[i*2048], (length-(i*2048)));
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}
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} |