Emergency help

Hi , I am a PHP beginner. I have some problems to need some helps. I created an encrypted file that include some sensitive data. Then I don't want anybody else to decrypt it, the condition is that: The final file caller must the exactly right caller and the created time is the original time at which I encrypted file. For example: File A call B, B call C, I want to get A's filename and created time. If they are match, return the decrypted file. The question is how to get A's filename and created time??? And I don't want anyone see the source code, so I want to add the code as a module or a binary file to PHP. How can I get it??? The task is very emergent. Help!!! If anyone can give me the answer I appreciate very much. Hope to hear you soon. Regards! Annie Zhou Jan 8, 2001