cleanup: make PKI more aware of PrivateKeys (#65)

* cleanup: make PrivateKeys more aware of PKI

* re-center around PrivateKeys

* `public_key_type` -> `long_term_key_type`

* fix CI

examples/iso_dh/DY.Example.DH.Debug.fst

@@ -13,27 +13,27 @@ let debug () : traceful (option unit)  =
 
   // Generate private key for Alice
   let* alice_global_session_priv_key_id = initialize_private_keys alice in
-  generate_private_key alice alice_global_session_priv_key_id (Sign "DH.SigningKey");*
+  generate_private_key alice alice_global_session_priv_key_id (LongTermSigKey "DH.SigningKey");*
 
   // Generate private key for Bob
   let* bob_global_session_priv_key_id = initialize_private_keys bob in
-  generate_private_key bob bob_global_session_priv_key_id (Sign "DH.SigningKey");*
+  generate_private_key bob bob_global_session_priv_key_id (LongTermSigKey "DH.SigningKey");*
 
   // Store Bob's public key in Alice's state
   // 1. Retrieve Bob's private key from his session
   // 2. Compute the public key from the private key
   // 3. Initialize Alice's session to store public keys
   // 4. Install Bob's public key in Alice's public key store
-  let*? priv_key_bob = get_private_key bob bob_global_session_priv_key_id (Sign "DH.SigningKey") in
-  let pub_key_bob = vk priv_key_bob in
+  let*? priv_key_bob = get_private_key bob bob_global_session_priv_key_id (LongTermSigKey "DH.SigningKey") in
+  let*? pub_key_bob = compute_public_key bob bob_global_session_priv_key_id (LongTermSigKey "DH.SigningKey") in
   let* alice_global_session_pub_key_id = initialize_pki alice in
-  install_public_key alice alice_global_session_pub_key_id (Verify "DH.SigningKey") bob pub_key_bob;*
+  install_public_key alice alice_global_session_pub_key_id (LongTermSigKey "DH.SigningKey") bob pub_key_bob;*
 
   // Store Alice's public key in Bob's state
-  let*? priv_key_alice = get_private_key alice alice_global_session_priv_key_id (Sign "DH.SigningKey") in
-  let pub_key_alice = vk priv_key_alice in
+  let*? priv_key_alice = get_private_key alice alice_global_session_priv_key_id (LongTermSigKey "DH.SigningKey") in
+  let*? pub_key_alice = compute_public_key alice alice_global_session_priv_key_id (LongTermSigKey "DH.SigningKey") in
   let* bob_global_session_pub_key_id = initialize_pki bob in
-  install_public_key bob bob_global_session_pub_key_id (Verify "DH.SigningKey") alice pub_key_alice;*
+  install_public_key bob bob_global_session_pub_key_id (LongTermSigKey "DH.SigningKey") alice pub_key_alice;*
 
   let alice_global_session_ids: dh_global_sess_ids = {pki=alice_global_session_pub_key_id; private_keys=alice_global_session_priv_key_id} in
   let bob_global_session_ids: dh_global_sess_ids = {pki=bob_global_session_pub_key_id; private_keys=bob_global_session_priv_key_id} in
@@ -64,4 +64,4 @@ let debug () : traceful (option unit)  =
 //Run ``debug ()`` when the module loads
 #push-options "--warn_error -272"
 let _ = debug () Nil
-#pop-options
+#pop-options

examples/iso_dh/DY.Example.DH.Protocol.Stateful.Proof.fst

@@ -212,7 +212,7 @@ val send_msg2_proof:
 let send_msg2_proof tr global_sess_id bob bob_si =
   match get_state bob bob_si tr with
   | (Some (ResponderSentMsg2 alice gx gy y), tr) -> (
-    match get_private_key bob global_sess_id.private_keys (Sign "DH.SigningKey") tr with
+    match get_private_key bob global_sess_id.private_keys (LongTermSigKey "DH.SigningKey") tr with
     | (Some sk_b, tr) -> (
       let (n_sig, tr) = mk_rand SigNonce (principal_label bob) 32 tr in
       compute_message2_proof tr alice bob gx y sk_b n_sig
@@ -238,7 +238,7 @@ let prepare_msg3_proof tr global_sess_id alice alice_si bob msg_id =
   | (Some (InitiatorSentMsg1 bob x), tr) -> (
     match recv_msg msg_id tr with
     | (Some msg_bytes, tr) -> (
-      match get_public_key alice global_sess_id.pki (Verify "DH.SigningKey") bob tr with
+      match get_public_key alice global_sess_id.pki (LongTermSigKey "DH.SigningKey") bob tr with
       | (Some pk_b, tr) -> (
         match decode_and_verify_message2 msg_bytes alice x pk_b with
         | Some res -> (
@@ -301,7 +301,7 @@ val send_msg3_proof:
 let send_msg3_proof tr global_sess_id alice alice_si bob =
   match get_state alice alice_si tr with
   | (Some (InitiatorSendMsg3 bob gx gy k), tr') -> (
-    match get_private_key alice global_sess_id.private_keys (Sign "DH.SigningKey") tr' with
+    match get_private_key alice global_sess_id.private_keys (LongTermSigKey "DH.SigningKey") tr' with
     | (Some sk_a, tr') -> (
       let (n_sig, tr') = mk_rand SigNonce (principal_label alice) 32 tr' in
 
@@ -336,7 +336,7 @@ let verify_msg3_proof tr global_sess_id alice bob msg_id bob_si =
   | (Some (ResponderSentMsg2 alice gx gy y), tr) -> (
     match recv_msg msg_id tr with
     | (Some msg_bytes, tr) -> (
-      match get_public_key bob global_sess_id.pki (Verify "DH.SigningKey") alice tr with
+      match get_public_key bob global_sess_id.pki (LongTermSigKey "DH.SigningKey") alice tr with
       | (Some pk_a, tr) -> (
           decode_and_verify_message3_proof tr msg_bytes alice bob bob_si gx y pk_a;
 

examples/iso_dh/DY.Example.DH.Protocol.Stateful.fst

@@ -91,7 +91,7 @@ let send_msg2 global_sess_id bob bob_si =
   let*? session_state = get_state bob bob_si in
   guard_tr (ResponderSentMsg2? session_state);*?
   let ResponderSentMsg2 alice gx gy y = session_state in
-  let*? sk_b = get_private_key bob global_sess_id.private_keys (Sign "DH.SigningKey") in
+  let*? sk_b = get_private_key bob global_sess_id.private_keys (LongTermSigKey "DH.SigningKey") in
   let* n_sig = mk_rand SigNonce (principal_label bob) 32 in
   let msg = compute_message2 alice bob gx gy sk_b n_sig in
   let* msg_id = send_msg msg in
@@ -105,7 +105,7 @@ let prepare_msg3 global_sess_id alice alice_si bob msg_id =
   let*? session_state = get_state alice alice_si in
   guard_tr (InitiatorSentMsg1? session_state);*?
   let InitiatorSentMsg1 bob x = session_state in
-  let*? pk_b = get_public_key alice global_sess_id.pki (Verify "DH.SigningKey") bob in
+  let*? pk_b = get_public_key alice global_sess_id.pki (LongTermSigKey "DH.SigningKey") bob in
   let*? msg = recv_msg msg_id in
   let*? res:verify_msg2_result = return (decode_and_verify_message2 msg alice x pk_b) in
   trigger_event alice (Initiate2 alice bob res.gx res.gy res.k);*
@@ -118,7 +118,7 @@ let send_msg3 global_sess_id alice bob alice_si =
   let*? session_state = get_state alice alice_si in
   guard_tr (InitiatorSendMsg3? session_state);*?
   let InitiatorSendMsg3 bob gx gy x = session_state in
-  let*? sk_a = get_private_key alice global_sess_id.private_keys (Sign "DH.SigningKey") in
+  let*? sk_a = get_private_key alice global_sess_id.private_keys (LongTermSigKey "DH.SigningKey") in
   let* n_sig = mk_rand SigNonce (principal_label alice) 32 in
   let msg = compute_message3 alice bob gx gy sk_a n_sig in
   let* msg_id = send_msg msg in
@@ -130,7 +130,7 @@ let verify_msg3 global_sess_id alice bob msg_id bob_si =
   let*? session_state = get_state bob bob_si in
   guard_tr (ResponderSentMsg2? session_state);*?
   let ResponderSentMsg2 alice gx gy y = session_state in
-  let*? pk_a = get_public_key bob global_sess_id.pki (Verify "DH.SigningKey") alice in
+  let*? pk_a = get_public_key bob global_sess_id.pki (LongTermSigKey "DH.SigningKey") alice in
   let*? msg = recv_msg msg_id in
   let*? res:verify_msg3_result = return (decode_and_verify_message3 msg bob gx gy y pk_a) in
   trigger_event bob (Respond2 alice bob gx gy res.k);*

examples/iso_dh/DY.Example.DH.Protocol.Total.Proof.fst

@@ -130,7 +130,7 @@ val compute_message2_proof:
     event_triggered tr bob (Respond1 alice bob gx (dh_pk y) y) /\
     is_publishable tr gx /\
     bytes_invariant tr y /\
-    is_signature_key (SigKey "DH.SigningKey" empty) (principal_label bob) tr sk_b /\
+    is_private_key_for tr sk_b (LongTermSigKey "DH.SigningKey") bob /\
     is_secret (principal_label bob) tr n_sig /\
     SigNonce? (get_usage n_sig)
   )
@@ -175,7 +175,7 @@ val decode_and_verify_message2_proof:
   (requires
     is_publishable tr msg2_bytes /\
     is_secret (principal_state_label alice alice_si) tr x /\
-    is_verification_key (SigKey "DH.SigningKey" empty) (principal_label bob) tr pk_b
+    is_public_key_for tr pk_b (LongTermSigKey "DH.SigningKey") bob
   )
   (ensures (
     match decode_and_verify_message2 msg2_bytes alice x pk_b with
@@ -218,7 +218,7 @@ val compute_message3_proof:
     event_triggered tr alice (Initiate2 alice bob (dh_pk x) gy (dh x gy)) /\
     is_publishable tr gx /\ is_publishable tr gy /\
     gx = dh_pk x /\
-    is_signature_key (SigKey "DH.SigningKey" empty) (principal_label alice) tr sk_a /\
+    is_private_key_for tr sk_a (LongTermSigKey "DH.SigningKey") alice /\
     is_secret (principal_label alice) tr n_sig /\
     SigNonce? (get_usage n_sig)
   )
@@ -248,7 +248,7 @@ let compute_message3_proof tr alice bob gx gy x sk_a n_sig =
   assert(is_publishable tr (serialize message msg));
   ()
 
-#push-options "--ifuel 1 --z3rlimit 10"
+#push-options "--ifuel 1 --z3rlimit 25"
 val decode_and_verify_message3_proof:
   tr:trace ->
   msg3_bytes:bytes ->
@@ -259,7 +259,7 @@ val decode_and_verify_message3_proof:
     is_publishable tr msg3_bytes /\
     is_publishable tr gx /\
     is_secret (principal_state_label bob bob_si) tr y /\
-    is_verification_key (SigKey "DH.SigningKey" empty) (principal_label alice) tr pk_a
+    is_public_key_for tr pk_a (LongTermSigKey "DH.SigningKey") alice
   )
   (ensures (
     let gy = dh_pk y in

examples/nsl_pk/DY.Example.NSL.Debug.fst

@@ -17,27 +17,27 @@ let debug () : traceful (option unit)  =
 
   // Generate private key for Alice
   let* alice_global_session_priv_key_id = initialize_private_keys alice in
-  generate_private_key alice alice_global_session_priv_key_id (PkDec "NSL.PublicKey");*
+  generate_private_key alice alice_global_session_priv_key_id (LongTermPkEncKey "NSL.PublicKey");*
 
   // Generate private key for Bob
   let* bob_global_session_priv_key_id = initialize_private_keys bob in
-  generate_private_key bob bob_global_session_priv_key_id (PkDec "NSL.PublicKey");*
+  generate_private_key bob bob_global_session_priv_key_id (LongTermPkEncKey "NSL.PublicKey");*
 
   // Store Bob's public key in Alice's state
   // 1. Retrieve Bob's private key from his session
   // 2. Compute the public key from the private key
   // 3. Initialize Alice's session to store public keys
   // 4. Install Bob's public key in Alice's public key store
-  let*? priv_key_bob = get_private_key bob bob_global_session_priv_key_id (PkDec "NSL.PublicKey") in
-  let pub_key_bob = pk priv_key_bob in
+  let*? priv_key_bob = get_private_key bob bob_global_session_priv_key_id (LongTermPkEncKey "NSL.PublicKey") in
+  let*? pub_key_bob = compute_public_key bob bob_global_session_priv_key_id (LongTermPkEncKey "NSL.PublicKey") in
   let* alice_global_session_pub_key_id = initialize_pki alice in
-  install_public_key alice alice_global_session_pub_key_id (PkEnc "NSL.PublicKey") bob pub_key_bob;*
+  install_public_key alice alice_global_session_pub_key_id (LongTermPkEncKey "NSL.PublicKey") bob pub_key_bob;*
 
   // Store Alice's public key in Bob's state
-  let*? priv_key_alice = get_private_key alice alice_global_session_priv_key_id (PkDec "NSL.PublicKey") in
-  let pub_key_alice = pk priv_key_alice in
+  let*? priv_key_alice = get_private_key alice alice_global_session_priv_key_id (LongTermPkEncKey "NSL.PublicKey") in
+  let*? pub_key_alice = compute_public_key alice alice_global_session_priv_key_id (LongTermPkEncKey "NSL.PublicKey") in
   let* bob_global_session_pub_key_id = initialize_pki bob in
-  install_public_key bob bob_global_session_pub_key_id (PkEnc "NSL.PublicKey") alice pub_key_alice;*
+  install_public_key bob bob_global_session_pub_key_id (LongTermPkEncKey "NSL.PublicKey") alice pub_key_alice;*
 
   let alice_global_session_ids: nsl_global_sess_ids = {pki=alice_global_session_pub_key_id; private_keys=alice_global_session_priv_key_id} in
   let bob_global_session_ids: nsl_global_sess_ids = {pki=bob_global_session_pub_key_id; private_keys=bob_global_session_priv_key_id} in

examples/nsl_pk/DY.Example.NSL.Protocol.Stateful.Proof.fst

@@ -167,7 +167,7 @@ val send_msg1_proof:
 let send_msg1_proof tr global_sess_id alice sess_id =
   match get_state alice sess_id tr with
   | (Some (InitiatorSentMsg1 bob n_a), tr) -> (
-    match get_public_key alice global_sess_id.pki (PkEnc "NSL.PublicKey") bob tr with
+    match get_public_key alice global_sess_id.pki (LongTermPkEncKey "NSL.PublicKey") bob tr with
     | (None, tr) -> ()
     | (Some pk_b, tr) -> (
       let (nonce, tr) = mk_rand PkNonce (principal_label alice) 32 tr in
@@ -189,7 +189,7 @@ let prepare_msg2_proof tr global_sess_id bob msg_id =
   match recv_msg msg_id tr with
   | (None, tr) -> ()
   | (Some msg, tr) -> (
-    match get_private_key bob global_sess_id.private_keys (PkDec "NSL.PublicKey") tr with
+    match get_private_key bob global_sess_id.private_keys (LongTermPkEncKey "NSL.PublicKey") tr with
     | (None, tr) -> ()
     | (Some sk_b, tr) -> (
       decode_message1_proof tr bob msg sk_b
@@ -208,7 +208,7 @@ val send_msg2_proof:
 let send_msg2_proof tr global_sess_id bob sess_id =
   match get_state bob sess_id tr with
   | (Some (ResponderSentMsg2 alice n_a n_b), tr) -> (
-    match get_public_key bob global_sess_id.pki (PkEnc "NSL.PublicKey") alice tr with
+    match get_public_key bob global_sess_id.pki (LongTermPkEncKey "NSL.PublicKey") alice tr with
     | (None, tr) -> ()
     | (Some pk_a, tr) -> (
       let (nonce, tr) = mk_rand PkNonce (principal_label bob) 32 tr in
@@ -230,7 +230,7 @@ let prepare_msg3_proof tr global_sess_id alice sess_id msg_id =
   match recv_msg msg_id tr with
   | (None, tr) -> ()
   | (Some msg, tr) -> (
-    match get_private_key alice global_sess_id.private_keys (PkDec "NSL.PublicKey") tr with
+    match get_private_key alice global_sess_id.private_keys (LongTermPkEncKey "NSL.PublicKey") tr with
     | (None, tr) -> ()
     | (Some sk_a, tr) -> (
       match get_state alice sess_id tr with
@@ -253,7 +253,7 @@ val send_msg3_proof:
 let send_msg3_proof tr global_sess_id alice sess_id =
   match get_state alice sess_id tr with
   | (Some (InitiatorSentMsg3 bob n_a n_b), tr) -> (
-    match get_public_key alice global_sess_id.pki (PkEnc "NSL.PublicKey") bob tr with
+    match get_public_key alice global_sess_id.pki (LongTermPkEncKey "NSL.PublicKey") bob tr with
     | (None, tr) -> ()
     | (Some pk_b, tr) -> (
       let (nonce, tr) = mk_rand PkNonce (principal_label alice) 32 tr in
@@ -292,7 +292,7 @@ let prepare_msg4 tr global_sess_id bob sess_id msg_id =
   match recv_msg msg_id tr with
   | (None, tr) -> ()
   | (Some msg, tr) -> (
-    match get_private_key bob global_sess_id.private_keys (PkDec "NSL.PublicKey") tr with
+    match get_private_key bob global_sess_id.private_keys (LongTermPkEncKey "NSL.PublicKey") tr with
     | (None, tr) -> ()
     | (Some sk_b, tr) -> (
       match get_state bob sess_id tr with

examples/nsl_pk/DY.Example.NSL.Protocol.Stateful.fst

@@ -71,7 +71,7 @@ let send_msg1 global_sess_id alice sess_id =
   let*? st = get_state alice sess_id in
   guard_tr (InitiatorSentMsg1? st);*?
   let InitiatorSentMsg1 bob n_a = st in
-  let*? pk_b = get_public_key alice global_sess_id.pki (PkEnc "NSL.PublicKey") bob in
+  let*? pk_b = get_public_key alice global_sess_id.pki (LongTermPkEncKey "NSL.PublicKey") bob in
   let* nonce = mk_rand PkNonce (principal_label alice) 32 in
   let msg = compute_message1 alice bob pk_b n_a nonce in
   let* msg_id = send_msg msg in
@@ -80,7 +80,7 @@ let send_msg1 global_sess_id alice sess_id =
 val prepare_msg2: nsl_global_sess_ids -> principal -> timestamp -> traceful (option state_id)
 let prepare_msg2 global_sess_id bob msg_id =
   let*? msg = recv_msg msg_id in
-  let*? sk_b = get_private_key bob global_sess_id.private_keys (PkDec "NSL.PublicKey") in
+  let*? sk_b = get_private_key bob global_sess_id.private_keys (LongTermPkEncKey "NSL.PublicKey") in
   let*? msg1: message1 = return (decode_message1 bob msg sk_b) in
   let* n_b = mk_rand NoUsage (join (principal_label msg1.alice) (principal_label bob)) 32 in
   trigger_event bob (Respond1 msg1.alice bob msg1.n_a n_b);*
@@ -93,7 +93,7 @@ let send_msg2 global_sess_id bob sess_id =
   let*? st = get_state bob sess_id in
   guard_tr (ResponderSentMsg2? st);*?
   let ResponderSentMsg2 alice n_a n_b = st in
-  let*? pk_a = get_public_key bob global_sess_id.pki (PkEnc "NSL.PublicKey") alice in
+  let*? pk_a = get_public_key bob global_sess_id.pki (LongTermPkEncKey "NSL.PublicKey") alice in
   let* nonce = mk_rand PkNonce (principal_label bob) 32 in
   let msg = compute_message2 bob {n_a; alice;} pk_a n_b nonce in
   let* msg_id = send_msg msg in
@@ -102,7 +102,7 @@ let send_msg2 global_sess_id bob sess_id =
 val prepare_msg3: nsl_global_sess_ids -> principal -> state_id -> timestamp -> traceful (option unit)
 let prepare_msg3 global_sess_id alice sess_id msg_id =
   let*? msg = recv_msg msg_id in
-  let*? sk_a = get_private_key alice global_sess_id.private_keys (PkDec "NSL.PublicKey") in
+  let*? sk_a = get_private_key alice global_sess_id.private_keys (LongTermPkEncKey "NSL.PublicKey") in
   let*? st = get_state alice sess_id in
   guard_tr (InitiatorSentMsg1? st);*?
   let InitiatorSentMsg1 bob n_a = st in
@@ -116,7 +116,7 @@ let send_msg3 global_sess_id alice sess_id =
   let*? st = get_state alice sess_id in
   guard_tr (InitiatorSentMsg3? st);*?
   let InitiatorSentMsg3 bob n_a n_b = st in
-  let*? pk_b = get_public_key alice global_sess_id.pki (PkEnc "NSL.PublicKey") bob in
+  let*? pk_b = get_public_key alice global_sess_id.pki (LongTermPkEncKey "NSL.PublicKey") bob in
   let* nonce = mk_rand PkNonce (principal_label alice) 32 in
   let msg = compute_message3 alice bob pk_b n_b nonce in
   let* msg_id = send_msg msg in
@@ -125,7 +125,7 @@ let send_msg3 global_sess_id alice sess_id =
 val prepare_msg4: nsl_global_sess_ids -> principal -> state_id -> timestamp -> traceful (option unit)
 let prepare_msg4 global_sess_id bob sess_id msg_id =
   let*? msg = recv_msg msg_id in
-  let*? sk_b = get_private_key bob global_sess_id.private_keys (PkDec "NSL.PublicKey") in
+  let*? sk_b = get_private_key bob global_sess_id.private_keys (LongTermPkEncKey "NSL.PublicKey") in
   let*? st = get_state bob sess_id in
   guard_tr (ResponderSentMsg2? st);*?
   let ResponderSentMsg2 alice n_a n_b = st in

examples/nsl_pk/DY.Example.NSL.Protocol.Total.Proof.fst

@@ -73,7 +73,7 @@ val compute_message1_proof:
     // From random generation
     PkNonce? (get_usage nonce) /\
     // From PKI invariants
-    is_encryption_key (PkKey "NSL.PublicKey" empty) (principal_label bob) tr pk_b
+    is_public_key_for tr pk_b (LongTermPkEncKey "NSL.PublicKey") bob
   )
   (ensures is_publishable tr (compute_message1 alice bob pk_b n_a nonce))
 let compute_message1_proof tr alice bob pk_b n_a nonce =
@@ -93,7 +93,7 @@ val decode_message1_proof:
   Lemma
   (requires
     // From PrivateKeys invariants
-    is_decryption_key (PkKey "NSL.PublicKey" empty) (principal_label bob) tr sk_b /\
+    is_private_key_for tr sk_b (LongTermPkEncKey "NSL.PublicKey") bob /\
     // From the network
     bytes_invariant tr msg_cipher
   )
@@ -129,7 +129,7 @@ val compute_message2_proof:
     // From the random generation
     PkNonce? (get_usage nonce) /\
     // From the PKI
-    is_encryption_key (PkKey "NSL.PublicKey" empty) (principal_label msg1.alice) tr pk_a
+    is_public_key_for tr pk_a (LongTermPkEncKey "NSL.PublicKey") msg1.alice
   )
   (ensures
     is_publishable tr (compute_message2 bob msg1 pk_a n_b nonce)
@@ -153,7 +153,7 @@ val decode_message2_proof:
     // From the NSL state invariant
     is_secret (join (principal_label alice) (principal_label bob)) tr n_a /\
     // From the PrivateKeys invariant
-    is_decryption_key (PkKey "NSL.PublicKey" empty) (principal_label alice) tr sk_a /\
+    is_private_key_for tr sk_a (LongTermPkEncKey "NSL.PublicKey") alice /\
     // From the network
     bytes_invariant tr msg_cipher
   )
@@ -192,7 +192,7 @@ val compute_message3_proof:
     // From the random generation
     PkNonce? (get_usage nonce) /\
     // From the PKI
-    is_encryption_key (PkKey "NSL.PublicKey" empty) (principal_label bob) tr pk_b
+    is_public_key_for tr pk_b (LongTermPkEncKey "NSL.PublicKey") bob
   )
   (ensures
     is_publishable tr (compute_message3 alice bob pk_b n_b nonce)
@@ -217,7 +217,7 @@ val decode_message3_proof:
     // From the NSL state invariant
     get_label tr n_b == join (principal_label alice) (principal_label bob) /\
     // From the PrivateKeys invariant
-    is_decryption_key (PkKey "NSL.PublicKey" empty) (principal_label bob) tr sk_b /\
+    is_private_key_for tr sk_b (LongTermPkEncKey "NSL.PublicKey") bob /\
     // From the network
     bytes_invariant tr msg_cipher
   )