diff --git a/include/mbedtls/lms.h b/include/mbedtls/lms.h
index c3dc3aa..5773c79 100644
--- a/include/mbedtls/lms.h
+++ b/include/mbedtls/lms.h
@@ -341,7 +341,7 @@
                                       mbedtls_lms_algorithm_type_t type,
                                       mbedtls_lmots_algorithm_type_t otstype,
                                       int (*f_rng)(void *, unsigned char *, size_t),
-                                      void* p_rng, unsigned char *seed,
+                                      void* p_rng, const unsigned char *seed,
                                       size_t seed_size );
 
 /**
@@ -363,7 +363,7 @@
  * \return         A non-zero error code on failure.
  */
 int mbedtls_lms_calculate_public_key( mbedtls_lms_public_t *ctx,
-                                      mbedtls_lms_private_t *priv_ctx );
+                                      const mbedtls_lms_private_t *priv_ctx );
 
 /**
  * \brief                    This function exports an LMS public key from a
@@ -388,8 +388,9 @@
  * \return         \c 0 on success.
  * \return         A non-zero error code on failure.
  */
-int mbedtls_lms_export_public_key( mbedtls_lms_public_t *ctx, unsigned char *key,
-                                   size_t key_size, size_t *key_len );
+int mbedtls_lms_export_public_key( const mbedtls_lms_public_t *ctx,
+                                   unsigned char *key, size_t key_size,
+                                   size_t *key_len );
 
 /**
  * \brief                    This function creates a LMS signature, using a
@@ -429,8 +430,9 @@
  */
 int mbedtls_lms_sign( mbedtls_lms_private_t *ctx,
                       int (*f_rng)(void *, unsigned char *, size_t),
-                      void* p_rng, unsigned char *msg, unsigned int msg_size,
-                      unsigned char *sig, size_t sig_size, size_t *sig_len );
+                      void* p_rng, const unsigned char *msg,
+                      unsigned int msg_size, unsigned char *sig, size_t sig_size,
+                      size_t *sig_len );
 #endif /* defined(MBEDTLS_LMS_PRIVATE) */
 
 #ifdef __cplusplus