more refactoring towards #7272

9 files changed, 254 insertions, 469 deletions

diff --git a/src/exchange/taler-exchange-httpd_batch-withdraw.c b/src/exchange/taler-exchange-httpd_batch-withdraw.c
index 7352edfdd..de1b67e52 100644
--- a/src/exchange/taler-exchange-httpd_batch-withdraw.c
+++ b/src/exchange/taler-exchange-httpd_batch-withdraw.c
@@ -427,8 +427,9 @@ prepare_transaction (const struct TEH_RequestContext *rc,
       .bp = &pc->blinded_planchet
     };
 
-    ec = TEH_keys_denomination_sign_withdraw (
+    ec = TEH_keys_denomination_sign (
       &csds,
+      false,
       &pc->collectable.sig);
     if (TALER_EC_NONE != ec)
     {
diff --git a/src/exchange/taler-exchange-httpd_csr.c b/src/exchange/taler-exchange-httpd_csr.c
index 14d82ef11..7e9e7a584 100644
--- a/src/exchange/taler-exchange-httpd_csr.c
+++ b/src/exchange/taler-exchange-httpd_csr.c
@@ -179,9 +179,16 @@ TEH_handler_csr_melt (struct TEH_RequestContext *rc,
 
         /* derive r_pub */
         // FIXME-#7272: bundle all requests into one derivation request (TEH_keys_..., crypto helper, security module)
-        ec = TEH_keys_denomination_cs_r_pub_melt (denom_pub_hash,
-                                                  nonce,
-                                                  r_pub);
+        {
+          const struct TEH_CsDeriveData cdd = {
+            .h_denom_pub = denom_pub_hash,
+            .nonce = nonce
+          };
+
+          ec = TEH_keys_denomination_cs_r_pub (&cdd,
+                                               true,
+                                               r_pub);
+        }
         if (TALER_EC_NONE != ec)
         {
           GNUNET_break (0);
@@ -315,10 +322,14 @@ TEH_handler_csr_withdraw (struct TEH_RequestContext *rc,
   /* derive r_pub */
   {
     enum TALER_ErrorCode ec;
+    const struct TEH_CsDeriveData cdd = {
+      .h_denom_pub = &denom_pub_hash,
+      .nonce = &nonce
+    };
 
-    ec = TEH_keys_denomination_cs_r_pub_withdraw (&denom_pub_hash,
-                                                  &nonce,
-                                                  &ewv.details.cs_values);
+    ec = TEH_keys_denomination_cs_r_pub (&cdd,
+                                         false,
+                                         &ewv.details.cs_values);
     if (TALER_EC_NONE != ec)
     {
       GNUNET_break (0);
diff --git a/src/exchange/taler-exchange-httpd_keys.c b/src/exchange/taler-exchange-httpd_keys.c
index d430946cf..edfe50e58 100644
--- a/src/exchange/taler-exchange-httpd_keys.c
+++ b/src/exchange/taler-exchange-httpd_keys.c
@@ -2746,8 +2746,9 @@ TEH_keys_denomination_by_hash2 (
 
 
 enum TALER_ErrorCode
-TEH_keys_denomination_sign_withdraw (
+TEH_keys_denomination_sign (
   const struct TEH_CoinSignData *csd,
+  bool for_melt,
   struct TALER_BlindedDenominationSignature *bs)
 {
   struct TEH_KeyStateHandle *ksh;
@@ -2787,9 +2788,10 @@ TEH_keys_denomination_sign_withdraw (
 
       csr.h_cs = &hd->h_details.h_cs;
       csr.blinded_planchet = &bp->details.cs_blinded_planchet;
-      return TALER_CRYPTO_helper_cs_sign_withdraw (
+      return TALER_CRYPTO_helper_cs_sign (
         ksh->helpers->csdh,
         &csr,
+        for_melt,
         bs);
     }
   default:
@@ -2799,118 +2801,135 @@ TEH_keys_denomination_sign_withdraw (
 
 
 enum TALER_ErrorCode
-TEH_keys_denomination_batch_sign_withdraw (
+TEH_keys_denomination_batch_sign (
   const struct TEH_CoinSignData *csds,
   unsigned int csds_length,
+  bool for_melt,
   struct TALER_BlindedDenominationSignature *bss)
 {
   struct TEH_KeyStateHandle *ksh;
   struct HelperDenomination *hd;
-#if 0
+  struct TALER_CRYPTO_RsaSignRequest rsrs[csds_length];
+  struct TALER_CRYPTO_CsSignRequest csrs[csds_length];
+  struct TALER_BlindedDenominationSignature rs[csds_length];
+  struct TALER_BlindedDenominationSignature cs[csds_length];
+  unsigned int rsrs_pos = 0;
+  unsigned int csrs_pos = 0;
+  enum TALER_ErrorCode ec;
 
   ksh = TEH_keys_get_state ();
   if (NULL == ksh)
     return TALER_EC_EXCHANGE_GENERIC_KEYS_MISSING;
-  hd = GNUNET_CONTAINER_multihashmap_get (ksh->helpers->denom_keys,
-                                          &h_denom_pub->hash);
-  if (NULL == hd)
-    return TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN;
-  if (bp->cipher != hd->denom_pub.cipher)
-    return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
-  switch (hd->denom_pub.cipher)
-  {
-  case TALER_DENOMINATION_RSA:
-    TEH_METRICS_num_signatures[TEH_MT_SIGNATURE_RSA]++;
+  for (unsigned int i = 0; i<csds_length; i++)
+  {
+    const struct TALER_DenominationHashP *h_denom_pub = csds[i].h_denom_pub;
+    const struct TALER_BlindedPlanchet *bp = csds[i].bp;
+
+    hd = GNUNET_CONTAINER_multihashmap_get (ksh->helpers->denom_keys,
+                                            &h_denom_pub->hash);
+    if (NULL == hd)
+      return TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN;
+    if (bp->cipher != hd->denom_pub.cipher)
+      return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
+    switch (hd->denom_pub.cipher)
     {
-      struct TALER_CRYPTO_RsaSignRequest rsr = {
-        .h_rsa = &hd->h_details.h_rsa,
-        .msg = bp->details.rsa_blinded_planchet.blinded_msg,
-        .msg_size = bp->details.rsa_blinded_planchet.blinded_msg_size
-      };
-
-      return TALER_CRYPTO_helper_rsa_sign (
-        ksh->helpers->rsadh,
-        &rsr,
-        bs);
+    case TALER_DENOMINATION_RSA:
+      rsrs[rsrs_pos].h_rsa = &hd->h_details.h_rsa;
+      rsrs[rsrs_pos].msg
+        = bp->details.rsa_blinded_planchet.blinded_msg;
+      rsrs[rsrs_pos].msg_size
+        = bp->details.rsa_blinded_planchet.blinded_msg_size;
+      rsrs_pos++;
+      break;
+    case TALER_DENOMINATION_CS:
+      csrs[csrs_pos].h_cs = &hd->h_details.h_cs;
+      csrs[csrs_pos].blinded_planchet = &bp->details.cs_blinded_planchet;
+      csrs_pos++;
+      break;
+    default:
+      return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
     }
-  case TALER_DENOMINATION_CS:
-    TEH_METRICS_num_signatures[TEH_MT_SIGNATURE_CS]++;
-    {
-      struct TALER_CRYPTO_CsSignRequest csr;
+  }
 
-      csr.h_cs = &hd->h_details.h_cs;
-      csr.blinded_planchet = &bp->details.cs_blinded_planchet;
-      return TALER_CRYPTO_helper_cs_sign_withdraw (
-        ksh->helpers->csdh,
-        &csr,
-        bs);
+  if ( (0 != csrs_pos) &&
+       (0 != rsrs_pos) )
+  {
+    memset (rs,
+            0,
+            sizeof (rs));
+    memset (cs,
+            0,
+            sizeof (cs));
+  }
+  ec = TALER_EC_NONE;
+  if (0 != csrs_pos)
+  {
+    ec = TALER_CRYPTO_helper_cs_batch_sign (
+      ksh->helpers->csdh,
+      csrs,
+      csrs_pos,
+      for_melt,
+      (0 == rsrs_pos) ? bss : cs);
+    if (TALER_EC_NONE != ec)
+    {
+      for (unsigned int i = 0; i<csrs_pos; i++)
+        TALER_blinded_denom_sig_free (&cs[i]);
+      return ec;
     }
-  default:
-    return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
+    TEH_METRICS_num_signatures[TEH_MT_SIGNATURE_CS] += csrs_pos;
   }
-#endif
-}
-
-
-enum TALER_ErrorCode
-TEH_keys_denomination_sign_melt (
-  const struct TEH_CoinSignData *csd,
-  struct TALER_BlindedDenominationSignature *bs)
-{
-  const struct TALER_DenominationHashP *h_denom_pub = csd->h_denom_pub;
-  const struct TALER_BlindedPlanchet *bp = csd->bp;
-  struct TEH_KeyStateHandle *ksh;
-  struct HelperDenomination *hd;
-
-  ksh = TEH_keys_get_state ();
-  if (NULL == ksh)
-    return TALER_EC_EXCHANGE_GENERIC_KEYS_MISSING;
-  hd = GNUNET_CONTAINER_multihashmap_get (ksh->helpers->denom_keys,
-                                          &h_denom_pub->hash);
-  if (NULL == hd)
-    return TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN;
-  if (bp->cipher != hd->denom_pub.cipher)
-    return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
-  switch (hd->denom_pub.cipher)
+  if (0 != rsrs_pos)
   {
-  case TALER_DENOMINATION_RSA:
-    TEH_METRICS_num_signatures[TEH_MT_SIGNATURE_RSA]++;
+    ec = TALER_CRYPTO_helper_rsa_batch_sign (
+      ksh->helpers->rsadh,
+      rsrs,
+      rsrs_pos,
+      (0 == csrs_pos) ? bss : rs);
+    if (TALER_EC_NONE != ec)
     {
-      struct TALER_CRYPTO_RsaSignRequest rsr = {
-        .h_rsa = &hd->h_details.h_rsa,
-        .msg = bp->details.rsa_blinded_planchet.blinded_msg,
-        .msg_size = bp->details.rsa_blinded_planchet.blinded_msg_size
-      };
-
-      return TALER_CRYPTO_helper_rsa_sign (
-        ksh->helpers->rsadh,
-        &rsr,
-        bs);
+      for (unsigned int i = 0; i<csrs_pos; i++)
+        TALER_blinded_denom_sig_free (&cs[i]);
+      for (unsigned int i = 0; i<rsrs_pos; i++)
+        TALER_blinded_denom_sig_free (&rs[i]);
+      return ec;
     }
-  case TALER_DENOMINATION_CS:
+    TEH_METRICS_num_signatures[TEH_MT_SIGNATURE_RSA] += rsrs_pos;
+  }
+
+  if ( (0 != csrs_pos) &&
+       (0 != rsrs_pos) )
+  {
+    rsrs_pos = 0;
+    csrs_pos = 0;
+    for (unsigned int i = 0; i<csds_length; i++)
     {
-      struct TALER_CRYPTO_CsSignRequest csr;
+      const struct TALER_BlindedPlanchet *bp = csds[i].bp;
 
-      csr.h_cs = &hd->h_details.h_cs;
-      csr.blinded_planchet = &bp->details.cs_blinded_planchet;
-      TEH_METRICS_num_signatures[TEH_MT_SIGNATURE_CS]++;
-      return TALER_CRYPTO_helper_cs_sign_melt (
-        ksh->helpers->csdh,
-        &csr,
-        bs);
+      switch (bp->cipher)
+      {
+      case TALER_DENOMINATION_RSA:
+        bss[i] = rs[rsrs_pos++];
+        break;
+      case TALER_DENOMINATION_CS:
+        bss[i] = cs[csrs_pos++];
+        break;
+      default:
+        GNUNET_assert (0);
+      }
     }
-  default:
-    return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
   }
+  return TALER_EC_NONE;
 }
 
 
 enum TALER_ErrorCode
-TEH_keys_denomination_cs_r_pub_melt (
-  const struct TALER_DenominationHashP *h_denom_pub,
-  const struct TALER_CsNonce *nonce,
+TEH_keys_denomination_cs_r_pub (
+  const struct TEH_CsDeriveData *cdd,
+  bool for_melt,
   struct TALER_DenominationCSPublicRPairP *r_pub)
 {
+  const struct TALER_DenominationHashP *h_denom_pub = cdd->h_denom_pub;
+  const struct TALER_CsNonce *nonce = cdd->nonce;
   struct TEH_KeyStateHandle *ksh;
   struct HelperDenomination *hd;
 
@@ -2935,47 +2954,54 @@ TEH_keys_denomination_cs_r_pub_melt (
       .h_cs = &hd->h_details.h_cs,
       .nonce = nonce
     };
-    return TALER_CRYPTO_helper_cs_r_derive_melt (ksh->helpers->csdh,
-                                                 &cdr,
-                                                 r_pub);
+    return TALER_CRYPTO_helper_cs_r_derive (ksh->helpers->csdh,
+                                            &cdr,
+                                            for_melt,
+                                            r_pub);
   }
 }
 
 
 enum TALER_ErrorCode
-TEH_keys_denomination_cs_r_pub_withdraw (
-  const struct TALER_DenominationHashP *h_denom_pub,
-  const struct TALER_CsNonce *nonce,
-  struct TALER_DenominationCSPublicRPairP *r_pub)
+TEH_keys_denomination_cs_batch_r_pub (
+  const struct TEH_CsDeriveData *cdds,
+  unsigned int cdds_length,
+  bool for_melt,
+  struct TALER_DenominationCSPublicRPairP *r_pubs)
 {
   struct TEH_KeyStateHandle *ksh;
   struct HelperDenomination *hd;
+  struct TALER_CRYPTO_CsDeriveRequest cdrs[cdds_length];
 
   ksh = TEH_keys_get_state ();
   if (NULL == ksh)
   {
     return TALER_EC_EXCHANGE_GENERIC_KEYS_MISSING;
   }
-  hd = GNUNET_CONTAINER_multihashmap_get (ksh->helpers->denom_keys,
-                                          &h_denom_pub->hash);
-  if (NULL == hd)
+  for (unsigned int i = 0; i<cdds_length; i++)
   {
-    return TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN;
-  }
-  if (TALER_DENOMINATION_CS != hd->denom_pub.cipher)
-  {
-    return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
-  }
-  {
-    struct TALER_CRYPTO_CsDeriveRequest cdr = {
-      .h_cs = &hd->h_details.h_cs,
-      .nonce = nonce
-    };
+    const struct TALER_DenominationHashP *h_denom_pub = cdds[i].h_denom_pub;
+    const struct TALER_CsNonce *nonce = cdds[i].nonce;
 
-    return TALER_CRYPTO_helper_cs_r_derive_withdraw (ksh->helpers->csdh,
-                                                     &cdr,
-                                                     r_pub);
+    hd = GNUNET_CONTAINER_multihashmap_get (ksh->helpers->denom_keys,
+                                            &h_denom_pub->hash);
+    if (NULL == hd)
+    {
+      return TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN;
+    }
+    if (TALER_DENOMINATION_CS != hd->denom_pub.cipher)
+    {
+      return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
+    }
+    cdrs[i].h_cs = &hd->h_details.h_cs;
+    cdrs[i].nonce = nonce;
   }
+
+  return TALER_CRYPTO_helper_cs_r_batch_derive (ksh->helpers->csdh,
+                                                cdrs,
+                                                cdds_length,
+                                                for_melt,
+                                                r_pubs);
 }
 
 
diff --git a/src/exchange/taler-exchange-httpd_keys.h b/src/exchange/taler-exchange-httpd_keys.h
index 24ba1467c..7e8c1e995 100644
--- a/src/exchange/taler-exchange-httpd_keys.h
+++ b/src/exchange/taler-exchange-httpd_keys.h
@@ -264,91 +264,85 @@ struct TEH_CoinSignData
 
 
 /**
- * Request to sign @a csd for regular withdrawing.
+ * Request to sign @a csd for melting.
  *
  * @param csd identifies data to blindly sign and key to sign with
+ * @param for_melt true if this is for a melt operation
  * @param[out] bs set to the blind signature on success
  * @return #TALER_EC_NONE on success
  */
 enum TALER_ErrorCode
-TEH_keys_denomination_sign_withdraw (
+TEH_keys_denomination_sign (
   const struct TEH_CoinSignData *csd,
+  bool for_melt,
   struct TALER_BlindedDenominationSignature *bs);
 
 
 /**
- * Request to sign @a csds for regular withdrawing.
+ * Request to sign @a csds for melting.
  *
  * @param csds array with data to blindly sign (and keys to sign with)
  * @param csds_length length of @a csds array
+ * @param for_melt true if this is for a melt operation
  * @param[out] bss array set to the blind signature on success; must be of length @a csds_length
  * @return #TALER_EC_NONE on success
  */
 enum TALER_ErrorCode
-TEH_keys_denomination_batch_sign_withdraw (
+TEH_keys_denomination_batch_sign (
   const struct TEH_CoinSignData *csds,
   unsigned int csds_length,
+  bool for_melt,
   struct TALER_BlindedDenominationSignature *bss);
 
 
 /**
- * Request to sign @a csd for melting.
- *
- * @param csd identifies data to blindly sign and key to sign with
- * @param[out] bs set to the blind signature on success
- * @return #TALER_EC_NONE on success
+ * Information needed to derive the CS r_pub.
  */
-enum TALER_ErrorCode
-TEH_keys_denomination_sign_melt (
-  const struct TEH_CoinSignData *csd,
-  struct TALER_BlindedDenominationSignature *bs);
-
+struct TEH_CsDeriveData
+{
+  /**
+   * Hash of key to sign with.
+   */
+  const struct TALER_DenominationHashP *h_denom_pub;
 
-/**
- * Request to sign @a csds for melting.
- *
- * @param csds array with data to blindly sign (and keys to sign with)
- * @param csds_length length of @a csds array
- * @param[out] bss array set to the blind signature on success; must be of length @a csds_length
- * @return #TALER_EC_NONE on success
- */
-enum TALER_ErrorCode
-TEH_keys_denomination_batch_sign_melt (
-  const struct TEH_CoinSignData *csds,
-  unsigned int csds_length,
-  struct TALER_BlindedDenominationSignature *bss);
+  /**
+   * Nonce to use.
+   */
+  const struct TALER_CsNonce *nonce;
+};
 
 
 /**
- * Request to derive CS @a r_pub using the denomination corresponding to @a h_denom_pub
- * and @a nonce for withdrawing.
+ * Request to derive CS @a r_pub using the denomination and nonce from @a cdd.
  *
- * @param h_denom_pub hash of the public key to use to derive r_pub
- * @param nonce withdraw/refresh nonce
+ * @param cdd data to compute @a r_pub from
+ * @param for_melt true if this is for a melt operation
  * @param[out] r_pub where to write the result
  * @return #TALER_EC_NONE on success
  */
 enum TALER_ErrorCode
-TEH_keys_denomination_cs_r_pub_withdraw (
-  const struct TALER_DenominationHashP *h_denom_pub,
-  const struct TALER_CsNonce *nonce,
+TEH_keys_denomination_cs_r_pub (
+  const struct TEH_CsDeriveData *cdd,
+  bool for_melt,
   struct TALER_DenominationCSPublicRPairP *r_pub);
 
 
 /**
- * Request to derive CS @a r_pub using the denomination corresponding to @a h_denom_pub
- * and @a nonce for melting.
+ * Request to derive a bunch of CS @a r_pubs using the
+ * denominations and nonces from @a cdds.
  *
- * @param h_denom_pub hash of the public key to use to derive r_pub
- * @param nonce withdraw/refresh nonce
- * @param[out] r_pub where to write the result
+ * @param cdds array to compute @a r_pubs from
+ * @param cdds_length length of the @a cdds array
+ * @param for_melt true if this is for a melt operation
+ * @param[out] r_pubs array where to write the result; must be of length @a cdds_length
  * @return #TALER_EC_NONE on success
  */
 enum TALER_ErrorCode
-TEH_keys_denomination_cs_r_pub_melt (
-  const struct TALER_DenominationHashP *h_denom_pub,
-  const struct TALER_CsNonce *nonce,
-  struct TALER_DenominationCSPublicRPairP *r_pub);
+TEH_keys_denomination_cs_batch_r_pub (
+  const struct TEH_CsDeriveData *cdds,
+  unsigned int cdds_length,
+  bool for_melt,
+  struct TALER_DenominationCSPublicRPairP *r_pubs);
 
 
 /**
diff --git a/src/exchange/taler-exchange-httpd_refreshes_reveal.c b/src/exchange/taler-exchange-httpd_refreshes_reveal.c
index a0c8a6667..56848d581 100644
--- a/src/exchange/taler-exchange-httpd_refreshes_reveal.c
+++ b/src/exchange/taler-exchange-httpd_refreshes_reveal.c
@@ -215,10 +215,14 @@ check_commitment (struct RevealContext *rctx,
     case TALER_DENOMINATION_CS:
       {
         enum TALER_ErrorCode ec;
-
-        ec = TEH_keys_denomination_cs_r_pub_melt (
-          &rctx->rrcs[j].h_denom_pub,
-          &nonces[aoff],
+        const struct TEH_CsDeriveData cdd = {
+          .h_denom_pub = &rctx->rrcs[j].h_denom_pub,
+          .nonce = &nonces[aoff]
+        };
+
+        ec = TEH_keys_denomination_cs_r_pub (
+          &cdd,
+          true,
           &alg_values->details.cs_values);
         if (TALER_EC_NONE != ec)
         {
@@ -756,8 +760,9 @@ clean_age:
 
     // FIXME #7272: replace with a batch call that
     // passes all coins in once go!
-    ec = TEH_keys_denomination_sign_melt (
+    ec = TEH_keys_denomination_sign (
       &csd,
+      true,
       &rrcs[i].coin_sig);
     if (TALER_EC_NONE != ec)
     {
diff --git a/src/exchange/taler-exchange-httpd_withdraw.c b/src/exchange/taler-exchange-httpd_withdraw.c
index 71128bf53..253773639 100644
--- a/src/exchange/taler-exchange-httpd_withdraw.c
+++ b/src/exchange/taler-exchange-httpd_withdraw.c
@@ -455,8 +455,9 @@ TEH_handler_withdraw (struct TEH_RequestContext *rc,
     };
 
     /* Sign before transaction! */
-    ec = TEH_keys_denomination_sign_withdraw (
+    ec = TEH_keys_denomination_sign (
       &csd,
+      false,
       &wc.collectable.sig);
   }
   if (TALER_EC_NONE != ec)
diff --git a/src/include/taler_crypto_lib.h b/src/include/taler_crypto_lib.h
index 30a652682..9b658d741 100644
--- a/src/include/taler_crypto_lib.h
+++ b/src/include/taler_crypto_lib.h
@@ -2494,57 +2494,15 @@ struct TALER_CRYPTO_CsSignRequest
  *
  * @param dh helper process connection
  * @param req information about the key to sign with and the value to sign
+ * @param for_melt true if for melt operation
  * @param[out] bs set to the blind signature
  * @return #TALER_EC_NONE on success
  */
 enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_sign_melt (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsSignRequest *req,
-  struct TALER_BlindedDenominationSignature *bs);
-
-
-/**
- * Request helper @a dh to batch sign batch @a reqs.
- *
- * This operation will block until the signature has been obtained.  Should
- * this process receive a signal (that is not ignored) while the operation is
- * pending, the operation will fail.  Note that the helper may still believe
- * that it created the signature. Thus, signals may result in a small
- * differences in the signature counters.  Retrying in this case may work.
- *
- * @param dh helper process connection
- * @param reqs array with information about the keys to sign with and the values to sign
- * @param reqs_length length of the @a reqs array
- * @param[out] bss array set to the blind signatures, must be of length @a reqs_length!
- * @return #TALER_EC_NONE on success
- */
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_batch_sign_melt (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsSignRequest *reqs,
-  unsigned int reqs_length,
-  struct TALER_BlindedDenominationSignature *bss);
-
-
-/**
- * Request helper @a dh to sign @a req.
- *
- * This operation will block until the signature has been obtained.  Should
- * this process receive a signal (that is not ignored) while the operation is
- * pending, the operation will fail.  Note that the helper may still believe
- * that it created the signature. Thus, signals may result in a small
- * differences in the signature counters.  Retrying in this case may work.
- *
- * @param dh helper process connection
- * @param req information about the key to sign with and the value to sign
- * @param[out] bs set to the blind signature
- * @return #TALER_EC_NONE on success
- */
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_sign_withdraw (
+TALER_CRYPTO_helper_cs_sign (
   struct TALER_CRYPTO_CsDenominationHelper *dh,
   const struct TALER_CRYPTO_CsSignRequest *req,
+  bool for_melt,
   struct TALER_BlindedDenominationSignature *bs);
 
 
@@ -2560,14 +2518,16 @@ TALER_CRYPTO_helper_cs_sign_withdraw (
  * @param dh helper process connection
  * @param reqs information about the keys to sign with and the values to sign
  * @param reqs_length length of the @a reqs array
+ * @param for_melt true if this is for a melt operation
  * @param[out] bs array set to the blind signatures, must be of length @a reqs_length!
  * @return #TALER_EC_NONE on success
  */
 enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_batch_sign_withdraw (
+TALER_CRYPTO_helper_cs_batch_sign (
   struct TALER_CRYPTO_CsDenominationHelper *dh,
   const struct TALER_CRYPTO_CsSignRequest *reqs,
   unsigned int reqs_length,
+  bool for_melt,
   struct TALER_BlindedDenominationSignature *bss);
 
 
@@ -2621,20 +2581,20 @@ struct TALER_CRYPTO_CsDeriveRequest
  *
  * @param dh helper to process connection
  * @param cdr derivation input data
- * @param nonce witdhraw nonce
+ * @param for_melt true if this is for a melt operation
  * @param[out] crp set to the pair of R values
  * @return set to the error code (or #TALER_EC_NONE on success)
  */
 enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_r_derive_withdraw (
+TALER_CRYPTO_helper_cs_r_derive (
   struct TALER_CRYPTO_CsDenominationHelper *dh,
   const struct TALER_CRYPTO_CsDeriveRequest *cdr,
+  bool for_melt,
   struct TALER_DenominationCSPublicRPairP *crp);
 
 
 /**
- * Ask the helper to derive R using the information
- * from @a cdrs.
+ * Ask the helper to derive R using the information from @a cdrs.
  *
  * This operation will block until the R has been obtained.  Should
  * this process receive a signal (that is not ignored) while the operation is
@@ -2645,60 +2605,16 @@ TALER_CRYPTO_helper_cs_r_derive_withdraw (
  * @param dh helper to process connection
  * @param cdrs array with derivation input data
  * @param cdrs_length length of the @a cdrs array
+ * @param for_melt true if this is for a melt operation
  * @param[out] crp array set to the pair of R values, must be of length @a cdrs_length
  * @return set to the error code (or #TALER_EC_NONE on success)
  */
 enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_r_batch_derive_withdraw (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsDeriveRequest *cdrs,
-  unsigned int cdrs_length,
-  struct TALER_DenominationCSPublicRPairP *crps);
-
-
-/**
- * Ask the helper to derive R using the information
- * from @a cdr.
- *
- * This operation will block until the R has been obtained.  Should
- * this process receive a signal (that is not ignored) while the operation is
- * pending, the operation will fail.  Note that the helper may still believe
- * that it created the signature. Thus, signals may result in a small
- * differences in the signature counters.  Retrying in this case may work.
- *
- * @param dh helper to process connection
- * @param cdr derivation input data
- * @param[out] crp set to the pair of R values
- * @return set to the error code (or #TALER_EC_NONE on success)
- */
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_r_derive_melt (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsDeriveRequest *cdr,
-  struct TALER_DenominationCSPublicRPairP *crp);
-
-
-/**
- * Ask the helper to derive R using the information
- * from @a cdrs.
- *
- * This operation will block until the R has been obtained.  Should
- * this process receive a signal (that is not ignored) while the operation is
- * pending, the operation will fail.  Note that the helper may still believe
- * that it created the signature. Thus, signals may result in a small
- * differences in the signature counters.  Retrying in this case may work.
- *
- * @param dh helper to process connection
- * @param cdrs array with derivation input data
- * @param cdrs_length length of the @a cdrs array
- * @param[out] crps array set to the pair of R values, must be of length @a cdrs_length
- * @return set to the error code (or #TALER_EC_NONE on success)
- */
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_r_batch_derive_melt (
+TALER_CRYPTO_helper_cs_r_batch_derive (
   struct TALER_CRYPTO_CsDenominationHelper *dh,
   const struct TALER_CRYPTO_CsDeriveRequest *cdrs,
   unsigned int cdrs_length,
+  bool for_melt,
   struct TALER_DenominationCSPublicRPairP *crps);
 
 
diff --git a/src/util/crypto_helper_cs.c b/src/util/crypto_helper_cs.c
index 7554be40d..5f7d3d6f9 100644
--- a/src/util/crypto_helper_cs.c
+++ b/src/util/crypto_helper_cs.c
@@ -378,32 +378,17 @@ more:
 }
 
 
-/**
- * Request helper @a dh to sign @a msg using the public key corresponding to
- * @a h_denom_pub.
- *
- * This operation will block until the signature has been obtained.  Should
- * this process receive a signal (that is not ignored) while the operation is
- * pending, the operation will fail.  Note that the helper may still believe
- * that it created the signature. Thus, signals may result in a small
- * differences in the signature counters.  Retrying in this case may work.
- *
- * @param dh helper process connection
- * @param h_cs hash of the CS public key to use to sign
- * @param blinded_planchet blinded planchet containing c and nonce
- * @param for_melt true if the HKDF for melt should be used
- * @param[out] bs set to the blind signature
- * @return #TALER_EC_NONE on success
- */
-static enum TALER_ErrorCode
-helper_cs_sign (
+enum TALER_ErrorCode
+TALER_CRYPTO_helper_cs_sign (
   struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CsPubHashP *h_cs,
-  const struct TALER_BlindedCsPlanchet *blinded_planchet,
+  const struct TALER_CRYPTO_CsSignRequest *req,
   bool for_melt,
   struct TALER_BlindedDenominationSignature *bs)
 {
   enum TALER_ErrorCode ec = TALER_EC_INVALID;
+  const struct TALER_CsPubHashP *h_cs = req->h_cs;
+  const struct TALER_BlindedCsPlanchet *blinded_planchet =
+    req->blinded_planchet;
 
   bs->cipher = TALER_DENOMINATION_INVALID;
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
@@ -592,34 +577,6 @@ end:
 }
 
 
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_sign_melt (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsSignRequest *req,
-  struct TALER_BlindedDenominationSignature *bs)
-{
-  return helper_cs_sign (dh,
-                         req->h_cs,
-                         req->blinded_planchet,
-                         true,
-                         bs);
-}
-
-
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_sign_withdraw (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsSignRequest *req,
-  struct TALER_BlindedDenominationSignature *bs)
-{
-  return helper_cs_sign (dh,
-                         req->h_cs,
-                         req->blinded_planchet,
-                         false,
-                         bs);
-}
-
-
 void
 TALER_CRYPTO_helper_cs_revoke (
   struct TALER_CRYPTO_CsDenominationHelper *dh,
@@ -650,31 +607,15 @@ TALER_CRYPTO_helper_cs_revoke (
 }
 
 
-/**
- * Ask the helper to derive R using the @a nonce and denomination key
- * associated with @a h_cs.
- *
- * This operation will block until the R has been obtained.  Should
- * this process receive a signal (that is not ignored) while the operation is
- * pending, the operation will fail.  Note that the helper may still believe
- * that it created the signature. Thus, signals may result in a small
- * differences in the signature counters.  Retrying in this case may work.
- *
- * @param dh helper to process connection
- * @param h_cs hash of the CS public key to revoke
- * @param nonce witdhraw nonce
- * @param for_melt true if the HKDF for melt should be used
- * @param[out] crp set to the pair of R values
- * @return set to the error code (or #TALER_EC_NONE on success)
- */
-static enum TALER_ErrorCode
-helper_cs_r_derive (struct TALER_CRYPTO_CsDenominationHelper *dh,
-                    const struct TALER_CsPubHashP *h_cs,
-                    const struct TALER_CsNonce *nonce,
-                    bool for_melt,
-                    struct TALER_DenominationCSPublicRPairP *crp)
+enum TALER_ErrorCode
+TALER_CRYPTO_helper_cs_r_derive (struct TALER_CRYPTO_CsDenominationHelper *dh,
+                                 const struct TALER_CRYPTO_CsDeriveRequest *cdr,
+                                 bool for_melt,
+                                 struct TALER_DenominationCSPublicRPairP *crp)
 {
   enum TALER_ErrorCode ec = TALER_EC_INVALID;
+  const struct TALER_CsPubHashP *h_cs = cdr->h_cs;
+  const struct TALER_CsNonce *nonce = cdr->nonce;
 
   memset (crp,
           0,
@@ -852,51 +793,7 @@ more:
 
 
 enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_r_derive_withdraw (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsDeriveRequest *cdr,
-  struct TALER_DenominationCSPublicRPairP *crp)
-{
-  return helper_cs_r_derive (dh,
-                             cdr->h_cs,
-                             cdr->nonce,
-                             false,
-                             crp);
-}
-
-
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_r_derive_melt (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsDeriveRequest *cdr,
-  struct TALER_DenominationCSPublicRPairP *crp)
-{
-  return helper_cs_r_derive (dh,
-                             cdr->h_cs,
-                             cdr->nonce,
-                             true,
-                             crp);
-}
-
-
-/**
- * Request helper @a dh to sign batch of @a reqs requests.
- *
- * This operation will block until the signature has been obtained.  Should
- * this process receive a signal (that is not ignored) while the operation is
- * pending, the operation will fail.  Note that the helper may still believe
- * that it created the signature. Thus, signals may result in a small
- * differences in the signature counters.  Retrying in this case may work.
- *
- * @param dh helper process connection
- * @param reqs information about the keys to sign with and the values to sign
- * @param reqs_length length of the @a reqs array
- * @param for_melt true if this is for a melt operation
- * @param[out] bs array set to the blind signatures, must be of length @a reqs_length!
- * @return #TALER_EC_NONE on success
- */
-static enum TALER_ErrorCode
-helper_cs_batch_sign (
+TALER_CRYPTO_helper_cs_batch_sign (
   struct TALER_CRYPTO_CsDenominationHelper *dh,
   const struct TALER_CRYPTO_CsSignRequest *reqs,
   unsigned int reqs_length,
@@ -1141,53 +1038,7 @@ more:
 
 
 enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_batch_sign_melt (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsSignRequest *reqs,
-  unsigned int reqs_length,
-  struct TALER_BlindedDenominationSignature *bss)
-{
-  return helper_cs_batch_sign (dh,
-                               reqs,
-                               reqs_length,
-                               true,
-                               bss);
-}
-
-
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_batch_sign_withdraw (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsSignRequest *reqs,
-  unsigned int reqs_length,
-  struct TALER_BlindedDenominationSignature *bss)
-{
-  return helper_cs_batch_sign (dh,
-                               reqs,
-                               reqs_length,
-                               false,
-                               bss);
-}
-
-
-/**
- * Ask the helper to derive R using the information from @a cdrs.
- *
- * This operation will block until the R has been obtained.  Should
- * this process receive a signal (that is not ignored) while the operation is
- * pending, the operation will fail.  Note that the helper may still believe
- * that it created the signature. Thus, signals may result in a small
- * differences in the signature counters.  Retrying in this case may work.
- *
- * @param dh helper to process connection
- * @param cdrs array with derivation input data
- * @param cdrs_length length of the @a cdrs array
- * @param for_melt true if this is for a melt operation
- * @param[out] crp array set to the pair of R values, must be of length @a cdrs_length
- * @return set to the error code (or #TALER_EC_NONE on success)
- */
-static enum TALER_ErrorCode
-helper_cs_r_batch_derive (
+TALER_CRYPTO_helper_cs_r_batch_derive (
   struct TALER_CRYPTO_CsDenominationHelper *dh,
   const struct TALER_CRYPTO_CsDeriveRequest *cdrs,
   unsigned int cdrs_length,
@@ -1429,36 +1280,6 @@ more:
 }
 
 
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_r_batch_derive_withdraw (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsDeriveRequest *cdrs,
-  unsigned int cdrs_length,
-  struct TALER_DenominationCSPublicRPairP *crps)
-{
-  return helper_cs_r_batch_derive (dh,
-                                   cdrs,
-                                   cdrs_length,
-                                   false,
-                                   crps);
-}
-
-
-enum TALER_ErrorCode
-TALER_CRYPTO_helper_cs_r_batch_derive_melt (
-  struct TALER_CRYPTO_CsDenominationHelper *dh,
-  const struct TALER_CRYPTO_CsDeriveRequest *cdrs,
-  unsigned int cdrs_length,
-  struct TALER_DenominationCSPublicRPairP *crps)
-{
-  return helper_cs_r_batch_derive (dh,
-                                   cdrs,
-                                   cdrs_length,
-                                   true,
-                                   crps);
-}
-
-
 void
 TALER_CRYPTO_helper_cs_disconnect (
   struct TALER_CRYPTO_CsDenominationHelper *dh)
diff --git a/src/util/test_helper_cs.c b/src/util/test_helper_cs.c
index fdfc5c362..2dada0e19 100644
--- a/src/util/test_helper_cs.c
+++ b/src/util/test_helper_cs.c
@@ -295,9 +295,10 @@ test_r_derive (struct TALER_CRYPTO_CsDenominationHelper *dh)
         .nonce = &pd.blinded_planchet.details.cs_blinded_planchet.nonce
       };
 
-      ec = TALER_CRYPTO_helper_cs_r_derive_withdraw (
+      ec = TALER_CRYPTO_helper_cs_r_derive (
         dh,
         &cdr,
+        false,
         &alg_values.details.cs_values);
     }
     switch (ec)
@@ -391,9 +392,10 @@ test_r_derive (struct TALER_CRYPTO_CsDenominationHelper *dh)
     GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK,
                                 &nonce,
                                 sizeof (nonce));
-    ec = TALER_CRYPTO_helper_cs_r_derive_withdraw (dh,
-                                                   &cdr,
-                                                   &crp);
+    ec = TALER_CRYPTO_helper_cs_r_derive (dh,
+                                          &cdr,
+                                          false,
+                                          &crp);
     if (TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN != ec)
     {
       GNUNET_break (0);
@@ -443,9 +445,10 @@ test_signing (struct TALER_CRYPTO_CsDenominationHelper *dh)
                                       &pd.blinded_planchet.details.
                                       cs_blinded_planchet.nonce);
       alg_values.cipher = TALER_DENOMINATION_CS;
-      ec = TALER_CRYPTO_helper_cs_r_derive_withdraw (
+      ec = TALER_CRYPTO_helper_cs_r_derive (
         dh,
         &cdr,
+        false,
         &alg_values.details.cs_values);
       if (TALER_EC_NONE != ec)
         continue;
@@ -470,9 +473,10 @@ test_signing (struct TALER_CRYPTO_CsDenominationHelper *dh)
       csr.h_cs = &keys[i].h_cs;
       csr.blinded_planchet
         = &pd.blinded_planchet.details.cs_blinded_planchet;
-      ec = TALER_CRYPTO_helper_cs_sign_withdraw (
+      ec = TALER_CRYPTO_helper_cs_sign (
         dh,
         &csr,
+        false,
         &ds);
     }
     switch (ec)
@@ -571,9 +575,10 @@ test_signing (struct TALER_CRYPTO_CsDenominationHelper *dh)
     csr.h_cs = &rnd;
     csr.blinded_planchet
       = &pd.blinded_planchet.details.cs_blinded_planchet;
-    ec = TALER_CRYPTO_helper_cs_sign_withdraw (
+    ec = TALER_CRYPTO_helper_cs_sign (
       dh,
       &csr,
+      false,
       &ds);
     if (TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN != ec)
     {
@@ -635,10 +640,11 @@ test_batch_signing (struct TALER_CRYPTO_CsDenominationHelper *dh,
           &pd[i].blinded_planchet.details.cs_blinded_planchet.nonce);
         alg_values[i].cipher = TALER_DENOMINATION_CS;
       }
-      ec = TALER_CRYPTO_helper_cs_r_batch_derive_withdraw (
+      ec = TALER_CRYPTO_helper_cs_r_batch_derive (
         dh,
         cdr,
         batch_size,
+        false,
         crps);
       if (TALER_EC_NONE != ec)
         continue;
@@ -666,10 +672,11 @@ test_batch_signing (struct TALER_CRYPTO_CsDenominationHelper *dh,
         csr[i].blinded_planchet
           = &pd[i].blinded_planchet.details.cs_blinded_planchet;
       }
-      ec = TALER_CRYPTO_helper_cs_batch_sign_withdraw (
+      ec = TALER_CRYPTO_helper_cs_batch_sign (
         dh,
         csr,
         batch_size,
+        false,
         ds);
     }
     switch (ec)
@@ -773,10 +780,11 @@ test_batch_signing (struct TALER_CRYPTO_CsDenominationHelper *dh,
     csr.h_cs = &rnd;
     csr.blinded_planchet
       = &pd.blinded_planchet.details.cs_blinded_planchet;
-    ec = TALER_CRYPTO_helper_cs_batch_sign_withdraw (
+    ec = TALER_CRYPTO_helper_cs_batch_sign (
       dh,
       &csr,
       1,
+      false,
       &ds[0]);
     if (TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN != ec)
     {
@@ -843,9 +851,10 @@ perf_signing (struct TALER_CRYPTO_CsDenominationHelper *dh,
                                         &pd.blinded_planchet.details.
                                         cs_blinded_planchet.nonce);
         alg_values.cipher = TALER_DENOMINATION_CS;
-        ec = TALER_CRYPTO_helper_cs_r_derive_melt (
+        ec = TALER_CRYPTO_helper_cs_r_derive (
           dh,
           &cdr,
+          true,
           &alg_values.details.cs_values);
         if (TALER_EC_NONE != ec)
           continue;
@@ -873,9 +882,10 @@ perf_signing (struct TALER_CRYPTO_CsDenominationHelper *dh,
           csr.h_cs = &keys[i].h_cs;
           csr.blinded_planchet
             = &pd.blinded_planchet.details.cs_blinded_planchet;
-          ec = TALER_CRYPTO_helper_cs_sign_melt (
+          ec = TALER_CRYPTO_helper_cs_sign (
             dh,
             &csr,
+            true,
             &ds);
           if (TALER_EC_NONE != ec)
             break;