[testing] issue receipts add blind and unblind

9 files changed, 352 insertions, 84 deletions

diff --git a/src/donau/donau-httpd_batch-submit.c b/src/donau/donau-httpd_batch-submit.c
index 41bf396..c908c86 100644
--- a/src/donau/donau-httpd_batch-submit.c
+++ b/src/donau/donau-httpd_batch-submit.c
@@ -208,4 +208,4 @@ DH_handler_submit_receipts_post (struct DH_RequestContext *rc,
 }
 
 
-/* end of donau-httpd_post-submit-receipts.c */
+/* end of donau-httpd_post-submit-receipts.c */
\ No newline at end of file
diff --git a/src/include/donau_crypto_lib.h b/src/include/donau_crypto_lib.h
index 8181611..9bf2ea5 100644
--- a/src/include/donau_crypto_lib.h
+++ b/src/include/donau_crypto_lib.h
@@ -210,7 +210,7 @@ struct DONAU_BlindedDonationUnitSignature
 
 
 /**
- * @brief Type of (unblinded) donation receipts signatures for Donau.
+ * @brief Type of (unblinded) donation receipts signatures for Taler.
  */
 struct DONAU_DonationUnitSignature
 {
@@ -326,14 +326,6 @@ struct DONAU_BkpSignData
 /** USED?
  * Hash of a budikeypair array
  */
-// struct DONAU_BudiKeyPairsHashP
-// {
-//   struct GNUNET_HashCode hash;
-// };
-
-/** USED?
- * Hash of a budikeypair array
- */
 // struct DONAU_BudiHashP
 // {
 //   struct GNUNET_HashCode hash;
@@ -347,6 +339,38 @@ struct DONAU_UniqueDonorIdentifierHashP
   struct GNUNET_HashCode hash;
 };
 
+/**
+ * Hash of a budikeypair array
+ */
+struct DONAU_BudiHashP
+{
+  struct GNUNET_HashCode hash;
+};
+
+/**
+ * @brief Inputs needed from the donau for blind signing.
+ */
+struct DONAU_BatchIssueValues
+{
+  /**
+   * Input values.
+   */
+  struct GNUNET_CRYPTO_BlindingInputValues *blinding_inputs;
+};
+
+/**
+ * Master key material for the deriviation of
+ * blinding factors during issuing receipts.
+ */
+struct DONAU_BudiMasterSecretP
+{
+
+  /**
+   * Key material.
+   */
+  uint32_t key_data[8];
+
+};
 
 /* ********************* charity eddsa signing ************************** */
 
@@ -425,7 +449,7 @@ DONAU_donation_statement_verify (
   const struct DONAU_DonauSignatureP *statement_sig);
 
 
-///* ********************* donau blind signing ************************** */
+/* ********************* donau blind signing ************************** */
 
 /**
  * Verify donation receipt.
@@ -446,7 +470,7 @@ DONAU_donation_receipt_verify (
  * Free internals of @a donation_unit_sig, but not @a donation_unit_sig itself.
  *
  * @param[in] donation_unit_sig signature to free
-// */
+ */
 void
 DONAU_blinded_donation_unit_sig_free (
   struct DONAU_BlindedDonationUnitSignature *donation_unit_sig);
@@ -461,12 +485,12 @@ DONAU_blinded_donation_unit_sig_free (
  * @param budi_hash hash over the budi
  * @return #GNUNET_OK if the signature is valid
  */
-// enum GNUNET_GenericReturnValue
-// TALER_donation_unit_pub_verify (
-//   const struct DONAU_DonationUnitPublicKey *du_pub,
-//                                 const struct
-//                                 DONAU_DonationUnitSignature *du_sig,
-//                                 const struct DONAU_BudiHashP *budi_hash);
+enum GNUNET_GenericReturnValue
+TALER_donation_unit_pub_verify (const struct
+                                DONAU_DonationUnitPublicKey *du_pub,
+                                const struct
+                                DONAU_DonationUnitSignature *du_sig,
+                                const struct DONAU_BudiHashP *budi_hash);
 
 
 // FIXME: Copied from taler_crypto_lib.h, is anything of this necessary?
@@ -583,6 +607,82 @@ DONAU_blinded_donation_unit_sig_free (
 //                        const struct DONAU_ *c_hash);
 //
 
+/* ********************* client blind/unblind ************************** */
+
+/**
+ * Create a blinding secret @a bks given the client's @a ps and the alg_values
+ * from the exchange.
+ *
+ * @param ps secret to derive blindings from
+ * @param alg_values containing cipher and additional CS values
+ * @param[out] bks blinding secrets
+ */
+void
+DONAU_budi_secret_create (
+  const struct DONAU_BudiMasterSecretP *ps,
+  const struct DONAU_BatchIssueValues *alg_values,
+  union GNUNET_CRYPTO_BlindingSecretP *bks);
+
+
+/**
+ * Return the alg value singleton for creation of
+ * blinding secrets for RSA.
+ *
+ * @return singleton to use for RSA blinding
+ */
+const struct DONAU_BatchIssueValues *
+DONAU_donation_unit_ewv_rsa_singleton (void);
+
+
+/**
+ * Blind udi for blind signing with @a du_pub using blinding secret @a budi_secret.
+ *
+ * NOTE: As a particular oddity, the @a budi is only partially
+ * initialized by this function in the case of CS donation units. Here, the
+ * 'nonce' must be initialized separately!
+ *
+ * @param du_pub donation unit public key to blind for
+ * @param budi_secret blinding secret to use
+ * @param cs_nonce nonce used to derive session values,
+ *        could be NULL for ciphers that do not use it
+ * @param udi_nonce guarantees uniqueness, part of the message to blind
+ * @param h_tax_id hashed and salted tax id, part of the message to blind
+ * @param alg_values algorithm specific values to blind the udi
+ * @param[out] udi_hash resulting hashed @a h_tax_id with @a udi_nonce
+ * @param[out] budi blinded udi data to initialize
+ * @return #GNUNET_OK on success
+ */
+enum GNUNET_GenericReturnValue
+DONAU_donation_unit_blind (
+  const struct DONAU_DonationUnitPublicKey *du_pub,
+  const union GNUNET_CRYPTO_BlindingSecretP *budi_secret,
+  const union GNUNET_CRYPTO_BlindSessionNonce *cs_nonce,
+  const struct DONAU_UniqueDonorIdentifierNonce *udi_nonce,//message
+  const struct DONAU_HashDonorTaxId *h_tax_id, //message
+  const struct DONAU_BatchIssueValues *alg_values,
+  struct DONAU_UniqueDonorIdentifierHashP *udi_hash,
+  struct DONAU_BlindedUniqueDonorIdentifier *budi);
+
+
+/**
+ * Unblind blinded signature.
+ *
+ * @param[out] du_sig where to write the unblinded signature
+ * @param blind_du_sig the blinded signature
+ * @param budi_secret blinding secret to use
+ * @param udi_hash hash of udi for verification of the signature
+ * @param alg_values algorithm specific values
+ * @param du_pub public key used for signing
+ * @return #GNUNET_OK on success
+ */
+enum GNUNET_GenericReturnValue
+DONAU_donation_unit_sig_unblind (
+  struct DONAU_DonationUnitSignature *du_sig,
+  const struct DONAU_BlindedDonationUnitSignature *blind_du_sig,
+  const union GNUNET_CRYPTO_BlindingSecretP *budi_secret,
+  const struct DONAU_UniqueDonorIdentifierHashP *udi_hash,
+  const struct DONAU_BatchIssueValues *alg_values,
+  const struct DONAU_DonationUnitPublicKey *du_pub);
 
 /*********************** helpers ************************************************/
 /**
@@ -616,17 +716,6 @@ DONAU_donation_unit_group_get_key (
   struct GNUNET_HashCode *key);
 
 /**
- * @brief Inputs needed from the donau for blind signing.
- */
-struct TALER_DonauBatchIssueValues
-{
-  /**
-   * Input values.
-   */
-  struct GNUNET_CRYPTO_BlindingInputValues *blinding_inputs;
-};
-
-/**
  * Compute the hash of a Unique Donor Identifier.
  *
  * @param h_donor_tax_id hash of the tax id
@@ -639,5 +728,4 @@ DONAU_unique_donor_id_hash (const struct DONAU_HashDonorTaxId *h_donor_tax_id,
                             ,
                             struct DONAU_UniqueDonorIdentifierHashP *h_udi);
 
-
 #endif
diff --git a/src/include/donau_service.h b/src/include/donau_service.h
index 0654db9..722f321 100644
--- a/src/include/donau_service.h
+++ b/src/include/donau_service.h
@@ -708,7 +708,7 @@ struct DONAU_CsRBatchIssueResponse
        * Values contributed by the donau for the
        * respective donation receipts's batch-issue operation.
        */
-      struct TALER_DonauBatchIssueValues alg_values;
+      struct DONAU_BatchIssueValues alg_values;
 
     } ok;
 
diff --git a/src/include/donau_testing_lib.h b/src/include/donau_testing_lib.h
index 2a64ed4..1e2bd17 100644
--- a/src/include/donau_testing_lib.h
+++ b/src/include/donau_testing_lib.h
@@ -118,7 +118,8 @@ TALER_TESTING_cmd_charities_get (const char *label,
  * @param label the command label.
  * @param charity_reference reference for traits
  * @param year current year (mostly)
- * @param num_bkps number of budi key pairs
+ * @param donor_tax_id tax id of the donor
+ * @param salt for tax id hash
  * @param expected_response_code expected HTTP response code.
  * @return the command.
  */
@@ -126,7 +127,8 @@ struct TALER_TESTING_Command
 TALER_TESTING_cmd_issue_receipts (const char *label,
                                   const char *charity_reference,
                                   const uint64_t year,
-                                  const size_t num_bkp,
+                                  const char *donor_tax_id,
+                                  const char *salt,
                                   unsigned int expected_response_code);
 
 
@@ -134,17 +136,15 @@ TALER_TESTING_cmd_issue_receipts (const char *label,
  * Create a POST "batch-issue" command.
  *
  * @param label the command label.
+ * @param issue_receipt_reference reference for traits
  * @param year current or past year (mostly)
- * @param donor_tax_id current year (mostly)
- * @param salt current year (mostly)
  * @param expected_response_code expected HTTP response code.
  * @return the command.
  */
 struct TALER_TESTING_Command
 TALER_TESTING_cmd_submit_receipts (const char *label,
+                                  const char *issue_receipt_reference,
                                   const uint64_t year,
-                                  const char *donor_tax_id,
-                                  const char *salt,
                                   unsigned int expected_response_code);
 
 
@@ -190,7 +190,8 @@ TALER_TESTING_get_donau_url (
   op (charity_pub, const struct DONAU_CharityPublicKeyP)        \
   op (charity_id, const unsigned long long)        \
   op (donau_url, const char)                                                \
-  op (donau_keys, struct DONAU_Keys)
+  op (donau_keys, struct DONAU_Keys) \
+  op (salted_tax_id_hash, struct DONAU_HashDonorTaxId)
 
 
 /**
diff --git a/src/lib/donau_api_batch_submit_receipts.c b/src/lib/donau_api_batch_submit_receipts.c
index 4c53313..d0ddfe3 100644
--- a/src/lib/donau_api_batch_submit_receipts.c
+++ b/src/lib/donau_api_batch_submit_receipts.c
@@ -74,14 +74,14 @@ struct DONAU_DonorReceiptsToStatementHandle
  * @param num_drs number of donation receipts in @drs
  * @param drs donation receipts array
  * @param year corresponding year
- * @param h_donor_tax_id salted and hashed tax id
+ * @param h_tax_id salted and hashed tax id
  */
 json_t *
 submit_request_body_to_json (const size_t num_drs,
                              const struct
                              DONAU_DonationReceipt drs[num_drs],
                              const uint64_t year,
-                             const struct DONAU_HashDonorTaxId *h_donor_tax_id)
+                             const struct DONAU_HashDonorTaxId *h_tax_id)
 {
   json_t *donation_receipts = json_array ();
   GNUNET_assert (NULL != donation_receipts);
@@ -93,7 +93,7 @@ submit_request_body_to_json (const size_t num_drs,
                                   &drs[i].h_donation_unit_pub),
       GNUNET_JSON_pack_data_auto ("nonce",
                                   &drs[i].nonce),
-      DONAU_JSON_pack_donation_unit_sig ("donation_unit_sig",
+      DONAU_JSON_pack_donation_unit_sig ("donau_sig",
                                          &drs[i].donation_unit_sig));
     GNUNET_assert (0 ==
                    json_array_append_new (donation_receipts,
@@ -102,8 +102,8 @@ submit_request_body_to_json (const size_t num_drs,
   return GNUNET_JSON_PACK (
     GNUNET_JSON_pack_array_steal ("donation_receipts",
                                   donation_receipts),
-    GNUNET_JSON_pack_data_auto ("h_donor_tax_id",
-                                h_donor_tax_id),
+    GNUNET_JSON_pack_data_auto ("h_tax_number",
+                                h_tax_id),
     GNUNET_JSON_pack_uint64 ("donation_year",
                              year));
 }
@@ -187,7 +187,7 @@ DONAU_donor_receipts_to_statement (
   const size_t num_drs,
   const struct DONAU_DonationReceipt drs[num_drs],
   const uint64_t year,
-  const struct DONAU_HashDonorTaxId *h_donor_tax_id,
+  const struct DONAU_HashDonorTaxId *h_tax_id,
   DONAU_DonorReceiptsToStatementResultCallback cb,
   void *cls)
 {
@@ -215,7 +215,7 @@ DONAU_donor_receipts_to_statement (
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "submit_receipts_with_URL `%s'.\n",
               birh->url);
-  body = submit_request_body_to_json (num_drs, drs, year, h_donor_tax_id);
+  body = submit_request_body_to_json (num_drs, drs, year, h_tax_id);
   eh = DONAU_curl_easy_get_ (birh->url);
   if ( (NULL == eh) ||
        (GNUNET_OK !=
diff --git a/src/testing/test_donau_api.c b/src/testing/test_donau_api.c
index 98f1695..a0e9eca 100644
--- a/src/testing/test_donau_api.c
+++ b/src/testing/test_donau_api.c
@@ -95,13 +95,13 @@ run (void *cls,
       TALER_TESTING_cmd_issue_receipts ("issue-receipts",
                                         "post-charity",
                                         2024,
-                                        3, // number of budi key pairs
+                                        "7560001010000", // tax id
+                                        "1234", //salt for tax id hash
                                         MHD_HTTP_CREATED),
-//	  TALER_TESTING_cmd_submit_receipts ("submit-receipts",
-//										2024,
-//										"7560001010000", // tax id
-//										"1234", //salt
-//										MHD_HTTP_OK),
+	    TALER_TESTING_cmd_submit_receipts ("submit-receipts",
+                                        "issue-receipts", // cmd trait reference
+                                        2024,
+                                        MHD_HTTP_OK),
       TALER_TESTING_cmd_charity_delete ("delete-charity",
                                         "post-charity", // cmd trait reference
                                         &bearer,
diff --git a/src/testing/testing_api_cmd_issue_receipts.c b/src/testing/testing_api_cmd_issue_receipts.c
index bea1be2..12062ed 100644
--- a/src/testing/testing_api_cmd_issue_receipts.c
+++ b/src/testing/testing_api_cmd_issue_receipts.c
@@ -83,6 +83,16 @@ struct StatusState
    */
   struct DONAU_Keys *keys;
 
+  /**
+   * Hashed and salted tax id of the donor.
+   */
+  struct DONAU_HashDonorTaxId *h_donor_tax_id;
+
+ /**
+  * Array of generated nonces for the udis.  
+  */
+  struct DONAU_UniqueDonorIdentifierNonce *udi_nonces;
+
 };
 
 
@@ -181,24 +191,50 @@ status_run (void *cls,
   ss->bkps
     = GNUNET_new_array (ss->num_bkp,
                         struct DONAU_BlindedUniqueDonorIdentifierKeyPair);
+  union GNUNET_CRYPTO_BlindingSecretP blinded_secrets[ss->num_bkp];
   for (size_t cnt = 0; cnt < ss->num_bkp; cnt++)
   {
-    struct GNUNET_CRYPTO_RsaBlindedMessage *rp;
-    struct DONAU_BlindedUniqueDonorIdentifier *bp = {0};
+    struct DONAU_UniqueDonorIdentifierNonce udi_nonce;
+    struct DONAU_BudiMasterSecretP ps;
+    const struct DONAU_BatchIssueValues *alg_values;
+    struct DONAU_BlindedUniqueDonorIdentifier *blinded_udi = &ss->bkps[cnt].blinded_udi;
+    struct DONAU_UniqueDonorIdentifierHashP udi_hash;
+    alg_values = DONAU_donation_unit_ewv_rsa_singleton ();
+
+    GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_STRONG,
+                            &ps,
+                            sizeof (ps));
+    DONAU_budi_secret_create (&ps,
+                              alg_values,
+                              &blinded_secrets[cnt]);
+    GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE,
+                        &udi_nonce,
+                        sizeof (udi_nonce));
+    GNUNET_assert (GNUNET_OK ==
+           DONAU_donation_unit_blind (&ss->keys->donation_unit_keys[0].key,
+                                      &blinded_secrets[cnt],
+                                      NULL, /* no cs-nonce needed for rsa */
+                                      &udi_nonce, 
+                                      ss->h_donor_tax_id,
+                                      alg_values,
+                                      &udi_hash,
+                                      blinded_udi));
+
     DONAU_donation_unit_pub_hash (&ss->keys->donation_unit_keys[0].key,
                                   &ss->bkps[cnt].h_donation_unit_pub);
-    bp = &ss->bkps[cnt].blinded_udi;
-    bp->blinded_message = GNUNET_new (struct GNUNET_CRYPTO_BlindedMessage);
-    bp->blinded_message->cipher = GNUNET_CRYPTO_BSA_RSA;
-    bp->blinded_message->rc = 1;
-    rp = &bp->blinded_message->details.rsa_blinded_message;
-    rp->blinded_msg_size = 1 + (size_t) GNUNET_CRYPTO_random_u64 (
-      GNUNET_CRYPTO_QUALITY_WEAK,
-      (1024 / 8) - 1);   // 1024 is the RSA key size
-    rp->blinded_msg = GNUNET_malloc (rp->blinded_msg_size);
-    GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK,
-                                rp->blinded_msg,
-                                rp->blinded_msg_size);
+    // struct GNUNET_CRYPTO_RsaBlindedMessage *rp;
+    // bp = &ss->bkps[cnt].blinded_udi;
+    // bp->blinded_message = GNUNET_new (struct GNUNET_CRYPTO_BlindedMessage);
+    // bp->blinded_message->cipher = GNUNET_CRYPTO_BSA_RSA;
+    // bp->blinded_message->rc = 1;
+    // rp = &bp->blinded_message->details.rsa_blinded_message;
+    // rp->blinded_msg_size = 1 + (size_t) GNUNET_CRYPTO_random_u64 (
+    //   GNUNET_CRYPTO_QUALITY_WEAK,
+    //   (1024 / 8) - 1);   // 1024 is the RSA key size
+    // rp->blinded_msg = GNUNET_malloc (rp->blinded_msg_size);
+    // GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK,
+    //                             rp->blinded_msg,
+    //                             rp->blinded_msg_size);
 
   }
   const struct DONAU_BlindedUniqueDonorIdentifierKeyPair *bkps = ss->bkps;
@@ -252,11 +288,40 @@ cleanup (void *cls,
 }
 
 
+/**
+ * Offer internal data from a "deposit" CMD, to other commands.
+ *
+ * @param cls closure.
+ * @param[out] ret result.
+ * @param trait name of the trait.
+ * @param index index number of the object to offer.
+ * @return #GNUNET_OK on success.
+ */
+static enum GNUNET_GenericReturnValue
+issue_receipts_traits (void *cls,
+                     const void **ret,
+                     const char *trait,
+                     unsigned int index)
+{
+  struct StatusState *ss = cls;
+  struct TALER_TESTING_Trait traits[] = {
+    TALER_TESTING_make_trait_salted_tax_id_hash (ss->h_donor_tax_id),
+    TALER_TESTING_trait_end ()
+  };
+
+  return TALER_TESTING_get_trait (traits,
+                                  ret,
+                                  trait,
+                                  index);
+}
+
+
 struct TALER_TESTING_Command
 TALER_TESTING_cmd_issue_receipts (const char *label,
                                   const char *charity_reference,
                                   const uint64_t year,
-                                  const size_t num_bkp,
+                                  const char *donor_tax_id,
+                                  const char *salt,
                                   unsigned int expected_response_code)
 {
   struct StatusState *ss;
@@ -266,14 +331,27 @@ TALER_TESTING_cmd_issue_receipts (const char *label,
   ss->year = year;
   ss->charity_reference = charity_reference;
   ss->expected_response_code = expected_response_code;
-  ss->num_bkp = num_bkp;
-
+  ss->num_bkp = 3;
+  struct DONAU_HashDonorTaxId h_donor_tax_id;
+  struct GNUNET_HashContext *hash_context;
+  hash_context = GNUNET_CRYPTO_hash_context_start ();
+
+  GNUNET_CRYPTO_hash_context_read (hash_context,
+                                   donor_tax_id,
+                                   sizeof((*donor_tax_id))),
+  GNUNET_CRYPTO_hash_context_read (hash_context,
+		  	  	  	  	  	  	   salt,
+                                   sizeof((*salt)));
+  GNUNET_CRYPTO_hash_context_finish (hash_context,
+		  	  	  	  	  	  	   &h_donor_tax_id.hash);
+  ss->h_donor_tax_id = &h_donor_tax_id;
   {
     struct TALER_TESTING_Command cmd = {
       .cls = ss,
       .label = label,
       .run = &status_run,
-      .cleanup = &cleanup
+      .cleanup = &cleanup,
+      .traits = &issue_receipts_traits
     };
 
     return cmd;
diff --git a/src/testing/testing_api_cmd_submit_receipts.c b/src/testing/testing_api_cmd_submit_receipts.c
index 7957152..8b5f5b0 100644
--- a/src/testing/testing_api_cmd_submit_receipts.c
+++ b/src/testing/testing_api_cmd_submit_receipts.c
@@ -195,9 +195,8 @@ cleanup (void *cls,
 
 struct TALER_TESTING_Command
 TALER_TESTING_cmd_submit_receipts (const char *label,
+                                  const char *issue_receipt_reference,
                                   const uint64_t year,
-								  const char *donor_tax_id,
-								  const char *salt,
                                   unsigned int expected_response_code)
 {
   struct StatusState *ss;
@@ -206,19 +205,7 @@ TALER_TESTING_cmd_submit_receipts (const char *label,
 
   ss->year = year;
   ss->expected_response_code = expected_response_code;
-  struct DONAU_HashDonorTaxId h_donor_tax_id;
-  struct GNUNET_HashContext *hash_context;
-  hash_context = GNUNET_CRYPTO_hash_context_start ();
-
-  GNUNET_CRYPTO_hash_context_read (hash_context,
-                                   donor_tax_id,
-                                   sizeof((*donor_tax_id))),
-  GNUNET_CRYPTO_hash_context_read (hash_context,
-		  	  	  	  	  	  	   salt,
-                                   sizeof((*salt)));
-  GNUNET_CRYPTO_hash_context_finish (hash_context,
-		  	  	  	  	  	  	   &h_donor_tax_id.hash);
-  ss->h_donor_tax_id = &h_donor_tax_id;
+  // ss->h_donor_tax_id = &h_donor_tax_id;
   {
     struct TALER_TESTING_Command cmd = {
       .cls = ss,
diff --git a/src/util/donau_crypto.c b/src/util/donau_crypto.c
index 6d86466..ffe7b53 100644
--- a/src/util/donau_crypto.c
+++ b/src/util/donau_crypto.c
@@ -172,3 +172,117 @@ DONAU_donation_receipt_verify (
                                          h_udi,
                                          sizeof (*h_udi));
 }
+
+enum GNUNET_GenericReturnValue
+DONAU_donation_unit_blind (
+  const struct DONAU_DonationUnitPublicKey *du_pub,
+  const union GNUNET_CRYPTO_BlindingSecretP *budi_secret,
+  const union GNUNET_CRYPTO_BlindSessionNonce *cs_nonce,
+  const struct DONAU_UniqueDonorIdentifierNonce *udi_nonce,//message
+  const struct DONAU_HashDonorTaxId *h_tax_id, //message
+  const struct DONAU_BatchIssueValues *alg_values,
+  struct DONAU_UniqueDonorIdentifierHashP *udi_hash,
+  struct DONAU_BlindedUniqueDonorIdentifier *budi)
+{
+  struct GNUNET_HashContext *hash_context;
+  hash_context = GNUNET_CRYPTO_hash_context_start ();
+
+  GNUNET_CRYPTO_hash_context_read (hash_context,
+                                   udi_nonce,
+                                   sizeof((*udi_nonce))),
+  GNUNET_CRYPTO_hash_context_read (hash_context,
+		  	  	  	  	  	  	       h_tax_id,
+                                   sizeof((*h_tax_id)));
+  GNUNET_CRYPTO_hash_context_finish (hash_context,
+		  	  	  	  	  	  	   &udi_hash->hash);
+
+  budi->blinded_message
+    = GNUNET_CRYPTO_message_blind_to_sign (du_pub->bsign_pub_key,
+                                           budi_secret,
+                                           cs_nonce,
+                                           udi_hash,
+                                           sizeof (*udi_hash),
+                                           alg_values->blinding_inputs);
+  if (NULL == budi->blinded_message)
+    return GNUNET_SYSERR;
+  return GNUNET_OK;
+}
+
+enum GNUNET_GenericReturnValue
+DONAU_donation_unit_sig_unblind (
+  struct DONAU_DonationUnitSignature *du_sig,
+  const struct DONAU_BlindedDonationUnitSignature *blind_du_sig,
+  const union GNUNET_CRYPTO_BlindingSecretP *budi_secret,
+  const struct DONAU_UniqueDonorIdentifierHashP *udi_hash,
+  const struct DONAU_BatchIssueValues *alg_values,
+  const struct DONAU_DonationUnitPublicKey *du_pub)
+{
+  du_sig->unblinded_sig
+    = GNUNET_CRYPTO_blind_sig_unblind (blind_du_sig->blinded_sig,
+                                       budi_secret,
+                                       udi_hash,
+                                       sizeof (*udi_hash),
+                                       alg_values->blinding_inputs,
+                                       du_pub->bsign_pub_key);
+  if (NULL == du_sig->unblinded_sig)
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+void
+DONAU_budi_secret_create (
+  const struct DONAU_BudiMasterSecretP *ps,
+  const struct DONAU_BatchIssueValues *alg_values,
+  union GNUNET_CRYPTO_BlindingSecretP *bks)
+{
+  const struct GNUNET_CRYPTO_BlindingInputValues *bi =
+    alg_values->blinding_inputs;
+
+  switch (bi->cipher)
+  {
+  case GNUNET_CRYPTO_BSA_INVALID:
+    GNUNET_break (0);
+    return;
+  case GNUNET_CRYPTO_BSA_RSA:
+    GNUNET_assert (GNUNET_YES ==
+                   GNUNET_CRYPTO_kdf (&bks->rsa_bks,
+                                      sizeof (bks->rsa_bks),
+                                      "bks",
+                                      strlen ("bks"),
+                                      ps,
+                                      sizeof(*ps),
+                                      NULL,
+                                      0));
+    return;
+  case GNUNET_CRYPTO_BSA_CS:
+    GNUNET_assert (GNUNET_YES ==
+                   GNUNET_CRYPTO_kdf (&bks->nonce,
+                                      sizeof (bks->nonce),
+                                      "bseed",
+                                      strlen ("bseed"),
+                                      ps,
+                                      sizeof(*ps),
+                                      &bi->details.cs_values,
+                                      sizeof(bi->details.cs_values),
+                                      NULL,
+                                      0));
+    return;
+  }
+  GNUNET_assert (0);
+}
+
+
+const struct DONAU_BatchIssueValues *
+DONAU_donation_unit_ewv_rsa_singleton ()
+{
+  static struct GNUNET_CRYPTO_BlindingInputValues bi = {
+    .cipher = GNUNET_CRYPTO_BSA_RSA
+  };
+  static struct DONAU_BatchIssueValues alg_values = {
+    .blinding_inputs = &bi
+  };
+  return &alg_values;
+}
\ No newline at end of file