diff --git a/doc/developer/blue-app-commands.pdf b/doc/developer/blue-app-commands.pdf
index 72a9b60..37d5471 100644
Binary files a/doc/developer/blue-app-commands.pdf and b/doc/developer/blue-app-commands.pdf differ
diff --git a/doc/developer/blue-app-commands.rst b/doc/developer/blue-app-commands.rst
index ee6fd81..db46f4a 100644
--- a/doc/developer/blue-app-commands.rst
+++ b/doc/developer/blue-app-commands.rst
@@ -104,8 +104,8 @@
 .. |eDRVout| replace:: :math:`\widetilde{\mathfrak{D}_\mathrm{out}}`
 .. |AKout|  replace::  :math:`\mathcal{AK}_\mathrm{amount}`
 .. |eAKout| replace:: :math:`\widetilde{\mathcal{AK}_\mathrm{amount}}`
-.. |vtf|    replace:: :math:`\mathit{view_tag_full}`
-.. |vt|     replace:: :math:`\mathit{view_tag}`
+.. |vtf|    replace:: :math:`\mathit{view\_tag\_full}`
+.. |vt|     replace:: :math:`\mathit{view\_tag}`
 
 
 .. |ctH|       replace:: :math:`\mathcal{H}_\mathrm{commitment}`
diff --git a/src/monero_api.h b/src/monero_api.h
index 0ce728d..89c746d 100644
--- a/src/monero_api.h
+++ b/src/monero_api.h
@@ -170,7 +170,8 @@ void monero_derive_public_key(unsigned char *x, unsigned char *drv_data, unsigne
                               unsigned char *ec_pub);
 void monero_secret_key_to_public_key(unsigned char *ec_pub, unsigned char *ec_priv);
 void monero_generate_key_image(unsigned char *img, unsigned char *P, unsigned char *x);
-void monero_derive_view_tag(unsigned char *view_tag, unsigned char *drv_data, unsigned int out_idx);
+void monero_derive_view_tag(unsigned char *view_tag, const unsigned char drv_data[static 32],
+                            unsigned int out_idx);
 
 void monero_derive_subaddress_public_key(unsigned char *x, unsigned char *pub,
                                          unsigned char *drv_data, unsigned int index);
diff --git a/src/monero_crypto.c b/src/monero_crypto.c
index df01036..d6fe718 100644
--- a/src/monero_crypto.c
+++ b/src/monero_crypto.c
@@ -522,7 +522,7 @@ void monero_generate_key_image(unsigned char *img, unsigned char *P, unsigned ch
 /* ----------------------------------------------------------------------- */
 /* ---                                                                 --- */
 /* ----------------------------------------------------------------------- */
-void monero_derive_view_tag(unsigned char *view_tag, unsigned char *drv_data,
+void monero_derive_view_tag(unsigned char *view_tag, const unsigned char drv_data[static 32],
                             unsigned int out_idx) {
     unsigned char varint[8 + 32 + 8];
     unsigned int len_varint;
@@ -532,7 +532,7 @@ void monero_derive_view_tag(unsigned char *view_tag, unsigned char *drv_data,
     len_varint = monero_encode_varint(varint + 8 + 32, 8, out_idx);
     len_varint += 8 + 32;
     monero_keccak_F(varint, len_varint, varint);
-    os_memmove(view_tag, varint, 1);
+    *view_tag = varint[0];
 }
 
 /* ======================================================================= */