From a02ab8f81b68b59ef5228ce30583d9388f9bab4a Mon Sep 17 00:00:00 2001
From: Gian Demarmels <gian@demarmels.org>
Date: Wed, 22 Dec 2021 12:52:54 +0100
Subject: added CS get R functionality and planchet setup

---
 src/include/taler_crypto_lib.h | 75 +++++++++++++++++++++++++++++-------------
 1 file changed, 53 insertions(+), 22 deletions(-)

(limited to 'src/include/taler_crypto_lib.h')

diff --git a/src/include/taler_crypto_lib.h b/src/include/taler_crypto_lib.h
index 8e5df1fc..542146cc 100644
--- a/src/include/taler_crypto_lib.h
+++ b/src/include/taler_crypto_lib.h
@@ -794,6 +794,9 @@ struct TALER_BlindedPlanchet
   } details;
 };
 
+/**
+ * Withdraw nonce for CS denominations
+ */
 struct TALER_WithdrawNonce
 {
   /**
@@ -802,6 +805,9 @@ struct TALER_WithdrawNonce
   struct GNUNET_CRYPTO_CsNonce nonce;
 };
 
+/**
+ * Withdraw nonce for CS denominations
+ */
 struct TALER_RefreshNonce
 {
   /**
@@ -810,6 +816,23 @@ struct TALER_RefreshNonce
   struct GNUNET_CRYPTO_CsNonce nonce;
 };
 
+/**
+ * Public R for Cs denominations
+ */
+struct TALER_DenominationCsPublicR
+{
+  struct GNUNET_CRYPTO_CsRPublic r_pub[2];
+};
+
+/**
+ * Secret r for Cs denominations
+ */
+
+struct TALER_DenominationCsPrivateR
+{
+  struct GNUNET_CRYPTO_CsRSecret r[2];
+};
+
 /**
  * @brief RSA Parameters to create blinded messages
  *
@@ -862,28 +885,6 @@ struct TALER_DenominationBlindMessageParams
   } details;
 };
 
-/**
- * @brief CS Blinding Secret parameters to derive blinding secrets
- *
- */
-struct TALER_PlanchetDeriveCsBlindingSecrets
-{
-  /**
-  * Secret to derive blinding secrets from
-  */
-  void *secret;
-
-  /**
-   * size of the secret to derive blinding secrets from
-   */
-  size_t secret_len;
-
-  /**
-   * public R_0 and R_1 are hashed too
-   */
-  struct GNUNET_CRYPTO_CsRPublic r_pub[2];
-};
-
 /**
  * @brief Public information about a coin (including the public key
  * of the coin, the denomination key and the signature with
@@ -1012,6 +1013,36 @@ void
 TALER_denom_sig_free (struct TALER_DenominationSignature *denom_sig);
 
 
+/**
+ * Function for CS signatures to derive the secret r_0 and r_1
+ *
+ * @param nonce withdraw nonce from a client
+ * @param denom_priv denomination privkey as long-term secret
+ * @param r the resulting r_0 and r_1
+ * @return enum GNUNET_GenericReturnValue, returns SYSERR when denom key has wrong type
+ */
+enum GNUNET_GenericReturnValue
+TALER_denom_cs_derive_r_secret (const struct TALER_WithdrawNonce *nonce,
+                                const struct
+                                TALER_DenominationPrivateKey *denom_priv,
+                                struct TALER_DenominationCsPrivateR *r);
+
+/**
+ * @brief Function for CS signatures to derive public R_0 and R_1
+ *
+ * @param nonce withdraw nonce from a client
+ * @param denom_priv denomination privkey as long-term secret
+ * @param r_pub the resulting R_0 and R_1
+ * @return enum GNUNET_GenericReturnValue
+ */
+
+enum GNUNET_GenericReturnValue
+TALER_denom_cs_derive_r_public (const struct TALER_WithdrawNonce *nonce,
+                                const struct
+                                TALER_DenominationPrivateKey *denom_priv,
+                                struct TALER_DenominationCsPublicR *r_pub);
+
+
 /**
  * Blind coin for blind signing with @a dk using blinding secret @a coin_bks.
  *
-- 
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