Is it possible to sign plain/ciphertext?

[SudoHenk]

Can I just like normal public key encryption sign something by decrypting the plaintext, or is this not allowed within ABE?

[jfdm]

Sorry, I do not follow the question?

[SudoHenk]

So the encryption schemes provide confidentiality (you cannot read the text being encrypted), but it does not provide authenticity. I want to prove that I am in possession of the attributes or policy. Am I allowed to digitally sign, just like as in public key encryption?