diff --git a/rebar.config b/rebar.config
index 07a123c..3cd89c7 100644
--- a/rebar.config
+++ b/rebar.config
@@ -10,6 +10,7 @@
 %% Compiler Options ============================================================
 {erl_opts,
  [{platform_define, "^[0-9]+", namespaced_types},
+  {platform_define, "^R1[4|5]", deprecated_crypto},
   debug_info,
   warnings_as_errors]}.
 
diff --git a/src/ec_file.erl b/src/ec_file.erl
index 3fe8a93..1885bde 100644
--- a/src/ec_file.erl
+++ b/src/ec_file.erl
@@ -94,9 +94,15 @@ md5sum(Value) ->
     
 %% @doc return an sha1sum checksum string or a binary. Same as unix utility of
 %%      same name.
+-ifdef(deprecated_crypto).
 -spec sha1sum(string() | binary()) -> string().
-sha1sum(Value) ->
+sha1sum(Value) ->  
+    hex(binary_to_list(crypto:sha(Value))).
+-else.
+-spec sha1sum(string() | binary()) -> string().
+sha1sum(Value) ->  
     hex(binary_to_list(crypto:hash(sha, Value))).
+-endif.
 
 %% @doc delete a file. Use the recursive option for directories.
 %% <pre>