taler-docs

commit d4403f695da0c70ed2404082104237d897486405
parent d0d42be33fc60dfb12869a2fa0c6529855572039
Author: Özgür Kesim <oec-taler@kesim.org>
Date:   Sat, 12 Apr 2025 21:41:12 +0200

[dd:pq-refresh] add stub for CoinSignature type

Diffstat:
M
design-documents/062-pq-refresh.rst
 | 
43
+++++++++++++++++++++++++------------------

1 file changed, 25 insertions(+), 18 deletions(-)
diff --git a/design-documents/062-pq-refresh.rst b/design-documents/062-pq-refresh.rst
@@ -40,7 +40,7 @@ derive the key material of a fresh coin from the old coin:
     # r = random seed, cs = coin secret, Cp = coin public key
     # pkD = denomination key
 
-    def RefreshDerivePQ(r, cs, Cp, pkD):
+    def RefreshDerive(r, cs, Cp, pkD):
         t = Hash1a("Refresh", Cp, r)
         s = SignDeterministic(cs, t)
         x = Hash1b(s)
@@ -61,15 +61,15 @@ all of the other.
 Protocol Modifications
 ^^^^^^^^^^^^^^^^^^^^^^
 
-Here is a short description of the main steps.  We will fill-in the details,
-once the paper is published.
+Here is a short description of the main steps.  We will provide further
+details, once the related paper [1]_ is published.
 
 1. **Melting/Commit Phase**:
 
    - Client chooses a master seed r and derives κ nonces r_1, ... r_κ.
    - Client generates κ refresh blinded coin candidates m_1,... m_κ from them.
-   - Sends dirty coin, r, all m_i and new denom-info to the exchange, with signature
-     σ_c of the dirty coins' private key over the request.
+   - Sends dirty coin, r, all m_i and new denom-info to the exchange, with
+     signature σ_c of the dirty coins' private key over the request.
    - Exchange verifies the request.
    - Exchange calculates h_m = H(m_1,...m_κ)
    - Exchange chooses γ from 1...K and signs m_γ, resulting in σ_γ.
@@ -105,7 +105,7 @@ TODO, see withdraw
 API endpoints
 ^^^^^^^^^^^^^^
 
-A new ``/melt`` request is needed, that takes the new `PQMeltRequest` as request
+A new ``/melt`` request is needed, that takes the new `NewMeltRequest` as request
 body, see below.
 As in the existing melting/commit phase, it invalidates the coin and prepares
 for exchanging of fresh coins.  Taler uses a global parameter ``kappa`` for the
@@ -147,9 +147,9 @@ Wire Formats
 
 Modified melt request structure:
 
-.. ts:def:: PQMeltRequest
+.. ts:def:: NewMeltRequest
 
-    interface PQMeltRequest {
+    interface NewMeltRequest {
        // The old coin's public key
        old_coin_pub: CoinPublicKey;
 
@@ -178,9 +178,9 @@ Modified melt request structure:
        // for the new coins to order.
        denoms_h: HashCode[];
 
-       // Hash of all the commitments k*n X_i as defined in the
-       // RefreshDerivePQ function.
-       h_Xs: HashCode;
+       // Seed from which the nonces for the κ coin candidates are derived
+       // from.
+       r_seed: HashCode;
 
        // Array of ``n`` entries with ``kappa`` many blinded coin candidates,
        // matching the respective entries in ``denoms_h``.
@@ -189,17 +189,17 @@ Modified melt request structure:
        // function.
        coin_evs: CoinEnvelope[][kappa];
 
-       // Signature by the `coin <coin-priv>` over `TALER_PQMeltCommitmentPS`.
-       confirm_sig: EddsaSignature;
+       // Signature by the `coin <coin-priv>` over `TALER_NewMeltCommitmentPS`.
+       confirm_sig: CoinSignature;
 
     }
 
-The new ``TALER_PQMeltCommitmentPS`` is defined as follows:
+The new ``TALER_NewMeltCommitmentPS`` is defined as follows:
 
-.. _TALER_PQMeltCommitmentPS:
+.. _TALER_NewMeltCommitmentPS:
 .. sourcecode:: c
 
-  struct TALER_PQMeltCommitmentPS {
+  struct TALER_newMeltCommitmentPS {
     /**
      * purpose.purpose = TALER_SIGNATURE_WALLET_COIN_MELT
      */
@@ -221,11 +221,18 @@ The new ``TALER_PQMeltCommitmentPS`` is defined as follows:
      */
     struct GNUNET_HashCode h_coin_evs;
     /**
-     * hash over of the required n*kappa transfer public keys, depths first.
+     * The seed for the nonces
      */
-    struct GNUNET_HashCode h_Xs;
+    struct GNUNET_HashCode r_seed;
   };
 
+TODO: definition of ``CoinSignature``
+
+.. ts:def:: CoinSignature
+
+   // TODO: this needs to be fully expanded into a new interface
+   type CoinSignature = string;
+
 
 
 Security Analysis