How can i use the policy encryption and decryption which includes more than 1 attribute?

[1ofvc]

such as
attrs:=[]string{"A", "B", "C"}
departAttr:="(A OR D) AND B"
without the Hash function to deal with departAttr, enc the msg with departAttr directly.
And the result is:

enc:

dec:
runtime error: invalid memory address or nil pointer dereference

If you see this problem，could you please give me some help. Thank you very much!

[1ofvc]

I‘ve sovled this problem!!!!