Hard question about decrypting?

[paasikivenpieru]

I got encrypted files, which are using algorithm 3DES-CBC. So, what i need to do, is to just open those files into the plain text.

 

Im trying to decrypt a data with PHP mcrypt_decrypt function.

In the encrypted data, "tag_pin_example.enc", vector IV is set to zeroes.(I dont know what does that actually mean)

 

I haven't work much with php and crypting, thats why I don't know to way how to 3DES-CBC works and what is the vector IV, but I still need to decrypt this file tag_pin_example.enc and make a decrypt generator for files likes that.

 

 

Here is my "brilliant" piece of code:

 

 

 

  ^<?php

  ^{//include 'todec.php';}

   

  ^{$inputFile = file("c:\\works\\debug\\kryptaus\\stralfors_pin\\tag_pin_example.enc");}

  ^{$key = "e1206e7240901c1a8111d077877a81ed";}

   

  ^{//$size = mcrypt_get_iv_size(MCRYPT_CAST_256, MCRYPT_MODE_CFB);  //i was jus trying to set vector IV}

  ^{//$iv = mcrypt_create_iv($size, 0);}

  ^{$decryptedData = mcrypt_decrypt(MCRYPT_3DES, $key, $inputFile,MCRYPT_MODE_CBC);}

  ^?>

 

 

 

 

The command prompt says: The size of key is too large for this algothrithm(It should be right size....i dont know).

And gives a warning: Attempt to Use an empty IV, which is NOT recommend in c:\pla pla pla..

 

I would be very pleased if someone knew what shall I do with this decrypting problem. The way how I open the file doesnt play any role,but I should just have to get them opened.