diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index 093b3bc..25f02ff 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -234,7 +234,7 @@
                     size_t output_max_len );
 typedef int (*mbedtls_pk_rsa_alt_sign_func)( void *ctx,
                     int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
-                    int mode, mbedtls_md_type_t md_alg, unsigned int hashlen,
+                    mbedtls_md_type_t md_alg, unsigned int hashlen,
                     const unsigned char *hash, unsigned char *sig );
 typedef size_t (*mbedtls_pk_rsa_alt_key_len_func)( void *ctx );
 #endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */