file_encrypt
This function encrypts a file based on a provided key.
bool file_encrypt(string input_file, string output_file, string encryption_key)
Parameters:
input_file
The name of the file to encrypt.
output_file
The name of the file that will contain the encrypted data.
encryption_key
The key that will be used to encrypt and later decrypt the data.
Return value:
true if the file was successfully encrypted, false otherwise.
Remarks:
This uses the AES-Rijndel 256-bit encryption algorithm, which is one of the most secure algorithms available to date. It has never been successfully cracked, and is used to protect files stored by various governments.
Files produced by file_encrypt are not compatible with strings produced by string_encrypt.
This function will encrypt any file, from text files to sounds, and the result can be used with the sound object (see the set_sound_decryption_key function for details).
The encrypted files are a few bytes longer than their decrypted equivalents.
The encrypted data is in binary form.
Example:

    // Encrypt a sound file and play it.

    sound test;

    void main()
    {
    if(!file_exists("test.wav"))
    {
    alert("Error", "Cannot find test.wav.");
    return;
    }
    if(!file_encrypt("test.wav", "test.dat", "you_are_not_hacking_into_me"))
    {
    alert("Error", "Could not encrypt test.wav.");
    return;
    }
    set_sound_decryption_key("you_are_not_hacking_into_me", true);
    test.load("test.dat");
    if(test.active==false)
    {
    alert("Error", "Cannot play encrypted sound. errorcode="+error);
    return;
    }
    test.play_wait();
    }