Is there a way to detect encryption used on a file?

Question

I have a small file that is encrypted and I want to see if it is a encryption method that has been broken or cracked.

Answer 1

If you are very very lucky and/or the encryption used is stupid there might be some information in the very first (or possibly last) part of the file.

But for any file encrypted by any tool worth it's name: NO

Answer 2

This is not entirely true. If the file is an exe or executable file, very likely you can detect the type of encryption it uses. http://www.peid.info/ this is the tool where u can detect the type of encryption uses. May not work on other files format such as doc, etc.