diff --git a/src/include/taler_json_lib.h b/src/include/taler_json_lib.h
index ffa440d56..1048b89f6 100644
--- a/src/include/taler_json_lib.h
+++ b/src/include/taler_json_lib.h
@@ -76,6 +76,26 @@ TALER_JSON_from_ecdsa_sig (const struct GNUNET_CRYPTO_EccSignaturePurpose *purpo
                            const struct GNUNET_CRYPTO_EcdsaSignature *signature);
 
 
+/**
+ * Convert RSA public key to JSON.
+ *
+ * @param pk public key to convert
+ * @return corresponding JSON encoding
+ */
+json_t *
+TALER_JSON_from_rsa_public_key (struct GNUNET_CRYPTO_rsa_PublicKey *pk);
+
+
+/**
+ * Convert RSA signature to JSON.
+ *
+ * @param sig signature to convert
+ * @return corresponding JSON encoding
+ */
+json_t *
+TALER_JSON_from_rsa_signature (struct GNUNET_CRYPTO_rsa_Signature *sig);
+
+
 /**
  * Convert binary data to a JSON string
  * with the base32crockford encoding.
diff --git a/src/mint/taler-mint-httpd_keystate.c b/src/mint/taler-mint-httpd_keystate.c
index d9eb81a9c..abc746e7d 100644
--- a/src/mint/taler-mint-httpd_keystate.c
+++ b/src/mint/taler-mint-httpd_keystate.c
@@ -116,8 +116,6 @@ static int reload_pipe[2];
 static json_t *
 denom_key_issue_to_json (const struct TALER_MINT_DenomKeyIssue *dki)
 {
-  char *buf;
-  size_t buf_len;
   json_t *dk_json = json_object ();
 
   json_object_set_new (dk_json,
@@ -134,13 +132,9 @@ denom_key_issue_to_json (const struct TALER_MINT_DenomKeyIssue *dki)
                        "stamp_expire_deposit",
                        TALER_JSON_from_abs (GNUNET_TIME_absolute_ntoh (dki->expire_spend)));
 
-  buf_len = GNUNET_CRYPTO_rsa_public_key_encode (dki->denom_pub,
-                                                 &buf);
   json_object_set_new (dk_json,
                        "denom_pub",
-                       TALER_JSON_from_data (buf,
-                                             buf_len));
-  GNUNET_free (buf);
+                       TALER_JSON_from_rsa_public_key (dki->denom_pub));
   json_object_set_new (dk_json,
                        "value",
                        TALER_JSON_from_amount (TALER_amount_ntoh (dki->value)));
diff --git a/src/mint/taler-mint-httpd_responses.c b/src/mint/taler-mint-httpd_responses.c
index dc51dee4b..1a0a7c997 100644
--- a/src/mint/taler-mint-httpd_responses.c
+++ b/src/mint/taler-mint-httpd_responses.c
@@ -581,15 +581,9 @@ TALER_MINT_reply_withdraw_sign_success (struct MHD_Connection *connection,
                                         const struct CollectableBlindcoin *collectable)
 {
   json_t *sig_json;
-  size_t sig_buf_size;
-  char *sig_buf;
   int ret;
 
-  sig_buf_size = GNUNET_CRYPTO_rsa_signature_encode (collectable->sig,
-                                                     &sig_buf);
-  sig_json = TALER_JSON_from_data (sig_buf,
-                                   sig_buf_size);
-  GNUNET_free (sig_buf);
+  sig_json = TALER_JSON_from_rsa_signature (collectable->sig);
   ret = TALER_MINT_reply_json_pack (connection,
                                     MHD_HTTP_OK,
                                     "{s:o}",
@@ -691,22 +685,14 @@ TALER_MINT_reply_refresh_reveal_success (struct MHD_Connection *connection,
   int newcoin_index;
   json_t *root;
   json_t *list;
-  char *buf;
-  size_t buf_size;
   int ret;
 
   root = json_object ();
   list = json_array ();
   json_object_set_new (root, "ev_sigs", list);
   for (newcoin_index = 0; newcoin_index < num_newcoins; newcoin_index++)
-  {
-    buf_size = GNUNET_CRYPTO_rsa_signature_encode (sigs[newcoin_index],
-                                                   &buf);
     json_array_append_new (list,
-                           TALER_JSON_from_data (buf,
-                                                 buf_size));
-    GNUNET_free (buf);
-  }
+                           TALER_JSON_from_rsa_signature (sigs[newcoin_index]));
   ret = TALER_MINT_reply_json (connection,
                                root,
                                MHD_HTTP_OK);
@@ -772,26 +758,18 @@ TALER_MINT_reply_refresh_link_success (struct MHD_Connection *connection,
   for (pos = ldl; NULL != pos; pos = pos->next)
   {
     json_t *obj;
-    char *buf;
-    size_t buf_len;
 
     obj = json_object ();
     json_object_set_new (obj, "link_enc",
                          TALER_JSON_from_data (ldl->link_data_enc->coin_priv_enc,
                                                sizeof (struct GNUNET_CRYPTO_EcdsaPrivateKey) +
                                                ldl->link_data_enc->blinding_key_enc_size));
-    buf_len = GNUNET_CRYPTO_rsa_public_key_encode (ldl->denom_pub,
-                                                   &buf);
-    json_object_set_new (obj, "denom_pub",
-                         TALER_JSON_from_data (buf,
-                                               buf_len));
-    GNUNET_free (buf);
-    buf_len = GNUNET_CRYPTO_rsa_signature_encode (ldl->ev_sig,
-                                                  &buf);
-    json_object_set_new (obj, "ev_sig",
-                         TALER_JSON_from_data (buf,
-                                               buf_len));
-    GNUNET_free (buf);
+    json_object_set_new (obj,
+                         "denom_pub",
+                         TALER_JSON_from_rsa_public_key (ldl->denom_pub));
+    json_object_set_new (obj,
+                         "ev_sig",
+                         TALER_JSON_from_rsa_signature (ldl->ev_sig));
     json_array_append_new (list, obj);
   }
 
diff --git a/src/util/json.c b/src/util/json.c
index a9d6dc5cc..84fac4c98 100644
--- a/src/util/json.c
+++ b/src/util/json.c
@@ -150,6 +150,50 @@ TALER_JSON_from_ecdsa_sig (const struct GNUNET_CRYPTO_EccSignaturePurpose *purpo
 }
 
 
+/**
+ * Convert RSA public key to JSON.
+ *
+ * @param pk public key to convert
+ * @return corresponding JSON encoding
+ */
+json_t *
+TALER_JSON_from_rsa_public_key (struct GNUNET_CRYPTO_rsa_PublicKey *pk)
+{
+  char *buf;
+  size_t buf_len;
+  json_t *ret;
+
+  buf_len = GNUNET_CRYPTO_rsa_public_key_encode (pk,
+                                                 &buf);
+  ret = TALER_JSON_from_data (buf,
+                              buf_len);
+  GNUNET_free (buf);
+  return ret;
+}
+
+
+/**
+ * Convert RSA signature to JSON.
+ *
+ * @param sig signature to convert
+ * @return corresponding JSON encoding
+ */
+json_t *
+TALER_JSON_from_rsa_signature (struct GNUNET_CRYPTO_rsa_Signature *sig)
+{
+  char *buf;
+  size_t buf_len;
+  json_t *ret;
+
+  buf_len = GNUNET_CRYPTO_rsa_signature_encode (sig,
+                                                &buf);
+  ret = TALER_JSON_from_data (buf,
+                              buf_len);
+  GNUNET_free (buf);
+  return ret;
+}
+
+
 /**
  * Convert binary data to a JSON string
  * with the base32crockford encoding.