1 files changed, 1 insertions, 1 deletions

diff --git a/src/lib/libcrypto/cast/cast.h b/src/lib/libcrypto/cast/cast.h
index 6cc5e8aa8c..e24e133099 100644
--- a/src/lib/libcrypto/cast/cast.h
+++ b/src/lib/libcrypto/cast/cast.h
@@ -82,7 +82,7 @@ typedef struct cast_key_st
         } CAST_KEY;
 
  
-void CAST_set_key(CAST_KEY *key, int len, unsigned char *data);
+void CAST_set_key(CAST_KEY *key, int len, const unsigned char *data);
 void CAST_ecb_encrypt(const unsigned char *in,unsigned char *out,CAST_KEY *key,
                       int enc);
 void CAST_encrypt(CAST_LONG *data,CAST_KEY *key);