anchor.diff:  
   (* ------------------------------------------------------------------------------- *)
   let remove self sid role hint =
  -    let key = bytes_of_key (sid,role,hint) in
  +    let key = bytes_of_key (Bytes.cbytes sid, role, hint) in
       let db  = DB.opendb self.filename in
   
       try
  
positive.code: 
  (* ------------------------------------------------------------------------------- *)
  let select self sid role hint =
      let key = bytes_of_key (sid,role,hint) in
  
      let select (db : DB.db) =
          let filter_record ((sinfo, ts) : StorableSession * _) =
  
negative.code: (* ------------------------------------------------------------------------------- *)
  type StorableSession = SessionInfo * PRF.masterSecret
  type SessionIndex = sessionID * Role * Cert.hint
  
  #if ideal
  type entry = sessionID * Role * Cert.hint * StorableSession
  type t = entry list  
  