diff --git a/scripts/create_genesis/create_genesis_info.py b/scripts/create_genesis/create_genesis_info.py
index 90fe763bc..b28fee478 100755
--- a/scripts/create_genesis/create_genesis_info.py
+++ b/scripts/create_genesis/create_genesis_info.py
@@ -104,7 +104,7 @@ if __name__ == '__main__':
                           "email" : email,
                           "password" : password,
                           "amount" : str(amount),
-                          "secret" : secret }
+                          "activation_code" : secret }
                         for pkh, (mnemonic, email, password, amount, secret) in secrets.iteritems()], f, indent=1)
     else:
         wallets = get_wallets( sys.argv[1] )
diff --git a/src/bin_client/test/queen_commitment.json b/src/bin_client/test/queen_commitment.json
index 0534e38cf..7928579d6 100644
--- a/src/bin_client/test/queen_commitment.json
+++ b/src/bin_client/test/queen_commitment.json
@@ -1,6 +1,6 @@
  {
   "mnemonic": ["flag", "quote", "will", "valley", "mouse", "chat", "hold", "prosper", "silk", "tent", "cruel", "cause", "demise", "bottom", "practice"],
-  "secret": "41f98b15efc63fa893d61d7d6eee4a2ce9427ac4",
+  "activation_code": "41f98b15efc63fa893d61d7d6eee4a2ce9427ac4",
   "amount": "72954577464032",
   "pkh": "tz1X4maqF9tC1Yn4jULjHRAyzjAtc25Z68TX",
   "password": "MHErskWPE6",
diff --git a/src/proto_alpha/lib_client/client_proto_context.ml b/src/proto_alpha/lib_client/client_proto_context.ml
index 9634cebd8..d8be3a892 100644
--- a/src/proto_alpha/lib_client/client_proto_context.ml
+++ b/src/proto_alpha/lib_client/client_proto_context.ml
@@ -237,26 +237,49 @@ let originate_contract
 type activation_key =
   { pkh : Ed25519.Public_key_hash.t ;
     amount : Tez.t ;
-    secret : Blinded_public_key_hash.secret ;
+    activation_code : Blinded_public_key_hash.activation_code ;
     mnemonic : string list ;
     password : string ;
     email : string ;
   }
 
+let raw_activation_key_encoding =
+  let open Data_encoding in
+  obj6
+    (req "pkh" Ed25519.Public_key_hash.encoding)
+    (req "amount" Tez.encoding)
+    (req "activation_code" Blinded_public_key_hash.activation_code_encoding)
+    (req "mnemonic" (list string))
+    (req "password" string)
+    (req "email" string)
+
 let activation_key_encoding =
+  (* Hack: allow compatibility with older encoding *)
   let open Data_encoding in
   conv
-    (fun { pkh ; amount ; secret ; mnemonic ; password ; email } ->
-       ( pkh, amount, secret, mnemonic, password, email ))
-    (fun ( pkh, amount, secret, mnemonic, password, email ) ->
-       { pkh ; amount ; secret ; mnemonic ; password ; email })
-    (obj6
-       (req "pkh" Ed25519.Public_key_hash.encoding)
-       (req "amount" Tez.encoding)
-       (req "secret" Blinded_public_key_hash.secret_encoding)
-       (req "mnemonic" (list string))
-       (req "password" string)
-       (req "email" string))
+    (fun { pkh ; amount ; activation_code ; mnemonic ; password ; email } ->
+       ( pkh, amount, activation_code, mnemonic, password, email ))
+    (fun ( pkh, amount, activation_code, mnemonic, password, email ) ->
+       { pkh ; amount ; activation_code ; mnemonic ; password ; email }) @@
+  splitted
+    ~binary:raw_activation_key_encoding
+    ~json:
+      (union [
+          case Json_only
+            raw_activation_key_encoding
+            (fun x -> Some x)
+            (fun x -> x) ;
+          case Json_only
+            (obj6
+               (req "pkh" Ed25519.Public_key_hash.encoding)
+               (req "amount" Tez.encoding)
+               (req "secret" Blinded_public_key_hash.activation_code_encoding)
+               (req "mnemonic" (list string))
+               (req "password" string)
+               (req "email" string))
+            (fun _ -> None)
+            (fun x -> x) ;
+        ])
 
 let read_key key =
   match Bip39.of_words key.mnemonic with
@@ -283,7 +306,7 @@ let claim_commitment (cctxt : #Proto_alpha.full)
        Ed25519.Public_key_hash.pp key.pkh) >>=? fun () ->
   let contents =
     Anonymous_operations
-      [ Activation { id = key.pkh ; secret = key.secret } ] in
+      [ Activation { id = key.pkh ; activation_code = key.activation_code } ] in
   Injection.inject_operation cctxt ?confirmations block contents >>=? fun (_oph, _op, _result as res) ->
   let pk_uri = Tezos_signer_backends.Unencrypted.make_pk pk in
   begin
diff --git a/src/proto_alpha/lib_client/client_proto_context.mli b/src/proto_alpha/lib_client/client_proto_context.mli
index 734476eec..dd3d31235 100644
--- a/src/proto_alpha/lib_client/client_proto_context.mli
+++ b/src/proto_alpha/lib_client/client_proto_context.mli
@@ -141,7 +141,7 @@ val dictate :
 type activation_key =
   { pkh : Ed25519.Public_key_hash.t ;
     amount : Tez.t ;
-    secret : Blinded_public_key_hash.secret ;
+    activation_code : Blinded_public_key_hash.activation_code ;
     mnemonic : string list ;
     password : string ;
     email : string ;
diff --git a/src/proto_alpha/lib_protocol/src/alpha_context.mli b/src/proto_alpha/lib_protocol/src/alpha_context.mli
index dc151b47a..e1f9c6bc4 100644
--- a/src/proto_alpha/lib_protocol/src/alpha_context.mli
+++ b/src/proto_alpha/lib_protocol/src/alpha_context.mli
@@ -745,7 +745,7 @@ and anonymous_operation =
     }
   | Activation of {
       id: Ed25519.Public_key_hash.t ;
-      secret: Blinded_public_key_hash.secret ;
+      activation_code: Blinded_public_key_hash.activation_code ;
     }
 
 and sourced_operation =
diff --git a/src/proto_alpha/lib_protocol/src/apply.ml b/src/proto_alpha/lib_protocol/src/apply.ml
index a73c40922..3ca7f1514 100644
--- a/src/proto_alpha/lib_protocol/src/apply.ml
+++ b/src/proto_alpha/lib_protocol/src/apply.ml
@@ -690,8 +690,9 @@ let apply_anonymous_operation ctxt kind =
         | Error _ -> Tez.zero in
       add_rewards ctxt reward >>=? fun ctxt ->
       return (ctxt, Double_baking_evidence_result [(* FIXME *)])
-  | Activation { id = pkh ; secret } ->
-      let blinded_pkh = Blinded_public_key_hash.of_ed25519_pkh secret pkh in
+  | Activation { id = pkh ; activation_code } ->
+      let blinded_pkh =
+        Blinded_public_key_hash.of_ed25519_pkh activation_code pkh in
       Commitment.get_opt ctxt blinded_pkh >>=? function
       | None -> fail (Invalid_activation { pkh })
       | Some amount ->
diff --git a/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.ml b/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.ml
index e07a313bb..ab85cd428 100644
--- a/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.ml
+++ b/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.ml
@@ -17,17 +17,17 @@ include Blake2B.Make(Base58)(struct
 let () =
   Base58.check_encoded_prefix b58check_encoding "btz1" 37
 
-let of_ed25519_pkh secret pkh =
-  hash_bytes ~key:secret [ Ed25519.Public_key_hash.to_bytes pkh ]
+let of_ed25519_pkh activation_code pkh =
+  hash_bytes ~key:activation_code [ Ed25519.Public_key_hash.to_bytes pkh ]
 
-type secret = MBytes.t
+type activation_code = MBytes.t
 
-let secret_size = Ed25519.Public_key_hash.size
-let secret_encoding = Data_encoding.Fixed.bytes secret_size
+let activation_code_size = Ed25519.Public_key_hash.size
+let activation_code_encoding = Data_encoding.Fixed.bytes activation_code_size
 
-let secret_of_hex h =
-  if Compare.Int.(String.length h <> secret_size * 2) then
-    invalid_arg "Blinded_public_key_hash.secret_of_hex" ;
+let activation_code_of_hex h =
+  if Compare.Int.(String.length h <> activation_code_size * 2) then
+    invalid_arg "Blinded_public_key_hash.activation_code_of_hex" ;
   MBytes.of_hex (`Hex h)
 
 module Index = struct
diff --git a/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.mli b/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.mli
index 7be2efba0..7e7da12cf 100644
--- a/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.mli
+++ b/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.mli
@@ -9,12 +9,12 @@
 
 include S.HASH
 
-type secret
-val secret_encoding : secret Data_encoding.t
+type activation_code
+val activation_code_encoding : activation_code Data_encoding.t
 
-val of_ed25519_pkh : secret -> Ed25519.Public_key_hash.t -> t
+val of_ed25519_pkh : activation_code -> Ed25519.Public_key_hash.t -> t
 
-val secret_of_hex : string -> secret
+val activation_code_of_hex : string -> activation_code
 
 module Index : sig
   type nonrec t = t
diff --git a/src/proto_alpha/lib_protocol/src/operation_repr.ml b/src/proto_alpha/lib_protocol/src/operation_repr.ml
index 6e7f7df57..d06778bfe 100644
--- a/src/proto_alpha/lib_protocol/src/operation_repr.ml
+++ b/src/proto_alpha/lib_protocol/src/operation_repr.ml
@@ -45,7 +45,7 @@ and anonymous_operation =
     }
   | Activation of {
       id: Ed25519.Public_key_hash.t ;
-      secret: Blinded_public_key_hash.secret ;
+      activation_code: Blinded_public_key_hash.activation_code ;
     }
 
 and sourced_operation =
@@ -368,15 +368,15 @@ module Encoding = struct
     (obj3
        (req "kind" (constant "activation"))
        (req "pkh" Ed25519.Public_key_hash.encoding)
-       (req "secret" Blinded_public_key_hash.secret_encoding))
+       (req "activation_code" Blinded_public_key_hash.activation_code_encoding))
 
   let activation_case tag =
     case tag activation_encoding
       (function
-        | Activation { id ; secret } -> Some ((), id, secret)
+        | Activation { id ; activation_code } -> Some ((), id, activation_code)
         | _ -> None
       )
-      (fun ((), id, secret) -> Activation { id ; secret })
+      (fun ((), id, activation_code) -> Activation { id ; activation_code })
 
   let anonymous_operations_case tag op_encoding =
     case tag
diff --git a/src/proto_alpha/lib_protocol/src/operation_repr.mli b/src/proto_alpha/lib_protocol/src/operation_repr.mli
index bdd855b5d..4f1bec011 100644
--- a/src/proto_alpha/lib_protocol/src/operation_repr.mli
+++ b/src/proto_alpha/lib_protocol/src/operation_repr.mli
@@ -45,7 +45,7 @@ and anonymous_operation =
     }
   | Activation of {
       id: Ed25519.Public_key_hash.t ;
-      secret: Blinded_public_key_hash.secret ;
+      activation_code: Blinded_public_key_hash.activation_code ;
     }
 
 and sourced_operation =