Encryption problem....

[Mike C]

I need to encrypt a large file, primarily to stop other people bypassing my application and running the file using basic windows apps. As the file can reach 650MB's this takes a long time to encrypt.

Is there anyway that I can encrypt just a part of this file, so as to make it unreadable ?

I have looked at many encryption apps but they all take ages. I don't know if this partial encryption is possible, so any thoughts on this subject appreciated.

Regards

Mike

[PRIVATE1]

Depending what kind of file it is you can .

1) Make a header in it .
or
2) Create you own File extention , this would be preffered .




[]P

[Mike C]

The file I need to encrypt is an AVI. Even if I just changed the extension, it could just as easily be changed back. Therefore simple encryption would be the ideal solution........I think ?

How would I go about making a header in it ?

Regards
Mike