add definition of all PS structs

src/types.ml

@@ -116,6 +116,8 @@ module Eddsa = struct
   (* EdDSA and ECDHE public keys always point on Curve25519
      and represented  using the standard 256 bits Ed25519 compact format,
      converted to Crockford Base32. *)
+  (* EdDSA signatures are transmitted as 64-bytes `base32`
+     binary-encoded objects with just the R and S values (base32_ binary-only). *)
   type pub = Mirage_crypto_ec.Ed25519.pub
 
   let pub_of_string s =