sec_tube_packet_crack

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

unsigned char iv[]="\xc9\xb1\x5f";
unsigned int old_icv;
unsigned int new_icv;
unsigned char encrypted_packet[]=
"\x85\x8a\x22\x52\x02\xfb\x44\xf2\xbf\x6d\x16\xf0\x15\x69\x05\x88\xac"
"\xc8\xe5\xa9\x89\x2c\x28\x71\xa0\xd3\x10\x31\x2a\xbd\x83\x09\x04\xce"
"\xaa\xa4\x3e\x01\xc9\x8a\xd4\xf7\xd4\x1a\xe2\xf8\x52\xc9\x28\x1b\x60"
"\xd5\x94\xe1\xd5\x15\x1a\x8b\x93\xa6\x9c\x55\xbf\x09\x27\x3a\xb9\x16"
"\xae\x94\xc9\xc0\x97\xed\xf0\xed\xe5\xd8\x87\x4a\x7e\xf9\x29\xac\x71"
"\x05\x4c\xa1\xbc\x16\x4d\x74\xb2\x2f\x33\x6f\x13\x4c\x50\x7a\x32\x34"
"\x8c\x90\xa2\x0e\x37\x7d\x90\x67\xd8\x56\x3a\x40\xb0\xbb\x3b\x8f\xf7"
"\x47\x01\xfd\xd9\x74\xa8\xaf\xf7\x41\x2c\x50\x5e\x03\x05\xaa\x28\x82"
"\xbb\x9b\x6a\x70\x27\xf2\xd9\x09\x36\xe0\x9d\x87\xe4\x02\x5d\x12\xb3"
"\x43\xb0\xf5\x94\x77\x81\xcf\x72\x43\x15\x89\xf6\x79\x4d\xad\x68\x84"
"\xcd\xae\x45\xb3\xb7\x5c\x4f\x6d\xa0\x40\xa1\xa3\x60\xdc\xfe\xd2\xb1"
"\xdc\xbb\xfb\x23\x8d\x1a\xcf\x4a\xf9\x78\x39\x51\xbd\xd9\x50\xe7\x9b"
"\x26\xd9\x58\xba\x8a\x74\x1d\xae\x14\xc9\x2f\x2c\x1e\x95\xea\x42\xa2"
"\xc5\x2b\x11\x41\x50\x34\x97\xf7\x59\xf0\xeb\x44\x03\x35\xdc\x59\x01"
"\xfc\x52\x2f\x80\x58\xb6\xab\xf3\x14\x30\xd3\x24\x43\xa5\x44\xf9\x8b"
"\x27\x04\xd2\x67\x6a\xe4\x16\xc0\xa8\xe1\x1a\xa3\x29\xce\x20\x2c\x2e"
"\xcc\x73\xc9\x1e\xe2\xb2\x91\x10\x9d\xb6\x20\x2b\xdb\x00\xa5\xcd\x7a"
"\x82\x36\x85\x26\x8c\xcc\x97\x61\xd7\x57\x25\x88\x66\xcc\x50\x94\x97"
"\x47\x56\xcd\x1b\x46\xe1\xe5\x80\x57\xd7\xf2\xff\xbc\x7c\x45\x75\xf5"
"\xd7\x70\x3b\x2b\x02\xc5\xb6\x90\xd8\x94\xf1\x40\x67";
unsigned char *decrypted_packet;

unsigned int decrypt(unsigned char *keystream);
unsigned char *create_keystream(unsigned char *pass);
unsigned char *rc4(unsigned char *password);
unsigned int crc32(unsigned char *packet, unsigned int len);
unsigned int chksum_crc32 (unsigned char *block, unsigned int length);
void chksum_crc32gentab ();
unsigned int crc_tab[256];

int main(int argc, char *argv[])
{
    unsigned char   *keystream;
    char        pass[6];
    FILE        *fs;

    if ( argc == 1 )
    {
        fprintf(stderr, "Usage: %s passlist.txt\n", argv[0]);
        return -1;
    }
    if (( fs = fopen(argv[1], "rb")) == NULL )
        return -1;

    for ( ; ; )
    {
        memset(pass, '\0', 6);
        if (fgets(pass, 6, fs) == NULL )
            break;

        printf("trying\"%s\"\n", pass);
        keystream = create_keystream(pass);
        old_icv = decrypt(keystream);
        new_icv = crc32(decrypted_packet, 336);
        free(decrypted_packet);
        if ( old_icv == new_icv )
            printf("password: %s\n", pass);
    }
    fclose(fs);
    return 0;
}
unsigned int decrypt(unsigned char *keystream)
{
    unsigned int    icv;
    register int    i;

    decrypted_packet = malloc(337 * sizeof(char));
    memset(decrypted_packet, '\0', 337);

    for ( i = 0; i < 336; i++ )
    {
        decrypted_packet[i] = encrypted_packet[i] ^ keystream[i];
    }
    memcpy((char *)&icv, &decrypted_packet+332, 4);

    return icv;
}
unsigned char *create_keystream(unsigned char *pass)
{
    unsigned char   *password = "\xc9\xb1\x5f\x74\x75\x64\x65\x73";
    unsigned char   *new_ks;
/*
    password = (unsigned char *)malloc(9 * sizeof(char));
    memset(password, '\0', 9);
    memcpy(password, iv, 3);
    memcpy(password+3, pass, 5);
*/
    new_ks = rc4(password);
//  free(password);

    return new_ks;
}

unsigned char *rc4(unsigned char *password)
{
    register int    i, j, k;
    unsigned char       s[256];
    unsigned char           *new_ks;
    unsigned char       temp;

    new_ks = (unsigned char *)malloc(337*sizeof(char));
    memset(new_ks, '\0', 337);
    //KSA
    j = 0;
    for ( i = 0; i < 256; i++ )
    {
        s[i] = i;
    }

    for ( i = 0; i < 256; i++ )
    {
        j = (j + s[i] + password[ i % 8])%256;
        temp = s[i];
        s[i] = s[j];
        s[j] = temp;
    }
    //PRGA
    i = 0;
    j = 0;
    for ( k = 0; k < 336; k++ )
    {
        i = (i + 1)%256;
        j = (j+s[i])%256;
        temp = s[i];
        s[i] = s[j];
        s[j] = temp;
        new_ks[k] = s[(s[i]+s[j])%256];
    }
    return new_ks;
}

unsigned int crc32(unsigned char *packet, unsigned int len)
{
    chksum_crc32gentab();

    return chksum_crc32(packet, len);
}

unsigned int chksum_crc32 (unsigned char *block, unsigned int length)
{
   register unsigned long crc;
   unsigned long i;

   crc = 0xFFFFFFFF;
   for (i = 0; i < length; i++)
   {
      crc = ((crc >> 8) & 0x00FFFFFF) ^ crc_tab[(crc ^ *block++) & 0xFF];
   }
   return (crc ^ 0xFFFFFFFF);
}

void chksum_crc32gentab ()
{
   unsigned long crc, poly;
   int i, j;

   poly = 0xEDB88320L;
   for (i = 0; i < 256; i++)
   {
      crc = i;
      for (j = 8; j > 0; j--)
      {
     if (crc & 1)
     {
        crc = (crc >> 1) ^ poly;
     }
     else
     {
        crc >>= 1;
     }
      }
      crc_tab[i] = crc;
   }
}