diff --git a/include/mbedtls/ecdh.h b/include/mbedtls/ecdh.h
index a6a5069..a919ad2 100644
--- a/include/mbedtls/ecdh.h
+++ b/include/mbedtls/ecdh.h
@@ -189,7 +189,7 @@
  *                  \c MBEDTLS_MPI_XXX error code on failure.
  */
 int mbedtls_ecdh_gen_public(mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q,
-                            int (*f_rng)(void *, unsigned char *, size_t),
+                            mbedtls_f_rng_t *f_rng,
                             void *p_rng);
 
 /**
@@ -225,7 +225,7 @@
  */
 int mbedtls_ecdh_compute_shared(mbedtls_ecp_group *grp, mbedtls_mpi *z,
                                 const mbedtls_ecp_point *Q, const mbedtls_mpi *d,
-                                int (*f_rng)(void *, unsigned char *, size_t),
+                                mbedtls_f_rng_t *f_rng,
                                 void *p_rng);
 
 /**
@@ -290,7 +290,7 @@
  */
 int mbedtls_ecdh_make_params(mbedtls_ecdh_context *ctx, size_t *olen,
                              unsigned char *buf, size_t blen,
-                             int (*f_rng)(void *, unsigned char *, size_t),
+                             mbedtls_f_rng_t *f_rng,
                              void *p_rng);
 
 /**
@@ -372,7 +372,7 @@
  */
 int mbedtls_ecdh_make_public(mbedtls_ecdh_context *ctx, size_t *olen,
                              unsigned char *buf, size_t blen,
-                             int (*f_rng)(void *, unsigned char *, size_t),
+                             mbedtls_f_rng_t *f_rng,
                              void *p_rng);
 
 /**
@@ -428,7 +428,7 @@
  */
 int mbedtls_ecdh_calc_secret(mbedtls_ecdh_context *ctx, size_t *olen,
                              unsigned char *buf, size_t blen,
-                             int (*f_rng)(void *, unsigned char *, size_t),
+                             mbedtls_f_rng_t *f_rng,
                              void *p_rng);
 
 #if defined(MBEDTLS_ECP_RESTARTABLE)