1 files changed, 2 insertions, 2 deletions
diff --git a/README.md b/README.md
index 81b03a8..0a28c8a 100644
--- a/README.md
+++ b/README.md
@@ -5,8 +5,8 @@ This is a small and portable implementation of the AES128 ECB encryption algorit
 The API is very simple and looks like this (I am using C99 `<stdint.h>`-style annotated types):
 
 ```C
-void AES128_ECB_encrypt(uint8_t* input, uint8_t* key, uint8_t* output);
-void AES128_ECB_decrypt(uint8_t* input, uint8_t* key, uint8_t* output);
+void AES128_ECB_encrypt(uint8_t* input, const uint8_t* key, uint8_t* output);
+void AES128_ECB_decrypt(uint8_t* input, const uint8_t* key, uint8_t* output);
 ```
 
 The module uses around 200 bytes of RAM and 2.5K ROM when compiled for ARM (~2K for Thumb but YMMV).