Fix typo in documentation
diff --git a/include/mbedtls/poly1305.h b/include/mbedtls/poly1305.h
index abe3690..5c69a81 100644
--- a/include/mbedtls/poly1305.h
+++ b/include/mbedtls/poly1305.h
@@ -106,7 +106,7 @@
                              const unsigned char key[32] );
 
 /**
- * \brief           This functions feeds an input bufer into an ongoing
+ * \brief           This functions feeds an input buffer into an ongoing
  *                  Poly1305 computation.
  *
  *                  It is called between \c mbedtls_cipher_cmac_starts() and