How to decrypt an encrypted payload?

[luochen1990]

Suppose we have the decryption key, is it possible to decrypt an encrypted payload with this DSL?

PS: What I want is to decrypt the packet defined in this script, according to this document.

[luochen1990]

I think an easy way to support decryption is to add a specifier namd encrypted which works similar to bytes but accepts an extra function argument which has type Bytes -> Bytes, so that we can easily decrypt payloads by providing such a function.