Because i want to hide my annotation value in order to don't know what kind of classes are used in this annotation.
I'm thinking about encryptuion of the annotation value using encryption algorithm e.g :RSA but i don't know if there is a way to decrypt this value at runtime.
I think that we can use java obfuscator in case we need to keep or not the annotations
Try asking on the aspectj users mailing list. Although this question is not aspectj specific (anyone who wants to obfuscate code, but needs runtime access to annotations will face this problem), there may be someone on the list who has some ideas.