From 36f551ff33ac0974788aff28d4b19390ca484f4b Mon Sep 17 00:00:00 2001
From: Lucien Heuzeveldt <lucienclaude.heuzeveldt@students.bfh.ch>
Date: Tue, 4 Jan 2022 17:46:36 +0100
Subject: [PATCH] set planchet detail cipher, add cipher checks

---
 src/include/taler_crypto_lib.h | 3 ++-
 src/util/crypto.c              | 7 +++++++
 src/util/denom.c               | 8 ++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/include/taler_crypto_lib.h b/src/include/taler_crypto_lib.h
index a20e51204..295d0e7be 100644
--- a/src/include/taler_crypto_lib.h
+++ b/src/include/taler_crypto_lib.h
@@ -1444,7 +1444,8 @@ TALER_planchet_setup_random (struct TALER_PlanchetSecretsP *ps,
  * @param ps secret planchet internals (for #TALER_planchet_to_coin)
  * @param[out] c_hash set to the hash of the public key of the coin (needed later)
  * @param[out] pd set to the planchet detail for TALER_MERCHANT_tip_pickup() and
- *               other withdraw operations
+ *               other withdraw operations, pd->blinded_planchet.cipher will be set
+ *               to cipher from dk
  * @return #GNUNET_OK on success
  */
 enum GNUNET_GenericReturnValue
diff --git a/src/util/crypto.c b/src/util/crypto.c
index 84d20d6ba..445b820aa 100644
--- a/src/util/crypto.c
+++ b/src/util/crypto.c
@@ -319,6 +319,7 @@ TALER_planchet_prepare (const struct TALER_DenominationPublicKey *dk,
     return GNUNET_SYSERR;
   }
 
+  pd->blinded_planchet.cipher = dk->cipher;
   TALER_denom_pub_hash (dk,
                         &pd->denom_pub_hash);
   return GNUNET_OK;
@@ -335,6 +336,12 @@ TALER_planchet_to_coin (const struct TALER_DenominationPublicKey *dk,
 {
   struct TALER_DenominationSignature sig;
 
+  if (dk->cipher != blind_sig->cipher)
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+
   switch (dk->cipher)
   {
   case TALER_DENOMINATION_RSA:
diff --git a/src/util/denom.c b/src/util/denom.c
index 908302600..a4965c050 100644
--- a/src/util/denom.c
+++ b/src/util/denom.c
@@ -112,6 +112,13 @@ TALER_denom_sign_blinded (struct TALER_BlindedDenominationSignature *denom_sig,
   memset (denom_sig,
           0,
           sizeof (*denom_sig));
+
+  if (blinded_planchet->cipher != denom_priv->cipher)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
   switch (denom_priv->cipher)
   {
   case TALER_DENOMINATION_INVALID:
@@ -394,6 +401,7 @@ TALER_denom_pub_verify (const struct TALER_DenominationPublicKey *denom_pub,
     GNUNET_break (0);
     return GNUNET_SYSERR;
   }
+
   switch (denom_pub->cipher)
   {
   case TALER_DENOMINATION_INVALID: