Marshal returns the wire-format encoding of m.

Meant for cases where you might want to get a value - assumes you want to copy the data if a policy passes for that message, field and action.

Meant for cases where you might want to set a value if a policy passes for that message, field and action.

`recursiveCrypt` examines all the field values of a message, and encrypts / decrypts each field if a policy passes for that message and field.

Unmarshal parses the wire-format message in b and places the result in m.