src/HOL/Auth/Yahalom2.thy

              X: synth (analz (sees lost Spy evs)) |]
           ==> Says Spy B X  # evs : yahalom lost"
 
          (*Alice initiates a protocol run*)
     YM1  "[| evs: yahalom lost;  A ~= B |]
-          ==> Says A B {|Agent A, Nonce (newN evs)|} # evs : yahalom lost"
+          ==> Says A B {|Agent A, Nonce (newN(length evs))|} # evs : yahalom lost"
 
          (*Bob's response to Alice's message.  Bob doesn't know who 
 	   the sender is, hence the A' in the sender field.*)
     YM2  "[| evs: yahalom lost;  B ~= Server;
              Says A' B {|Agent A, Nonce NA|} : set_of_list evs |]
-          ==> Says B Server {|Agent A, Agent B, Nonce NA, Nonce (newN evs)|}
+          ==> Says B Server {|Agent A, Agent B, Nonce NA, Nonce (newN(length evs))|}
                  # evs : yahalom lost"
 
          (*The Server receives Bob's message.  He responds by sending a
            new session key to Alice, with a packet for forwarding to Bob.
            Fields are reversed in the 2nd packet to prevent attacks.*)
     YM3  "[| evs: yahalom lost;  A ~= B;  A ~= Server;
              Says B' Server {|Agent A, Agent B, Nonce NA, Nonce NB|}
                : set_of_list evs |]
           ==> Says Server A
                {|Nonce NB, 
-                 Crypt (shrK A) {|Agent B, Key (newK evs), Nonce NA|},
-                 Crypt (shrK B) {|Nonce NB, Key (newK evs), Agent A|}|}
+                 Crypt (shrK A) {|Agent B, Key (newK(length evs)), Nonce NA|},
+                 Crypt (shrK B) {|Nonce NB, Key (newK(length evs)), Agent A|}|}
                  # evs : yahalom lost"
 
          (*Alice receives the Server's (?) message, checks her Nonce, and
            uses the new session key to send Bob his Nonce.*)
     YM4  "[| evs: yahalom lost;  A ~= Server;  A ~= B;