diff --git a/include/mbedtls/ecdsa.h b/include/mbedtls/ecdsa.h
index 2ecf349..119ee26 100644
--- a/include/mbedtls/ecdsa.h
+++ b/include/mbedtls/ecdsa.h
@@ -160,7 +160,7 @@
  */
 int mbedtls_ecdsa_sign(mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
                        const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
-                       int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
+                       mbedtls_f_rng_t *f_rng, void *p_rng);
 
 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
 /**
@@ -271,7 +271,7 @@
     mbedtls_mpi *r, mbedtls_mpi *s,
     const mbedtls_mpi *d,
     const unsigned char *buf, size_t blen,
-    int (*f_rng)(void *, unsigned char *, size_t),
+    mbedtls_f_rng_t *f_rng,
     void *p_rng,
     int (*f_rng_blind)(void *, unsigned char *, size_t),
     void *p_rng_blind,
@@ -473,7 +473,7 @@
                                   mbedtls_md_type_t md_alg,
                                   const unsigned char *hash, size_t hlen,
                                   unsigned char *sig, size_t sig_size, size_t *slen,
-                                  int (*f_rng)(void *, unsigned char *, size_t),
+                                  mbedtls_f_rng_t *f_rng,
                                   void *p_rng);
 
 /**
@@ -520,7 +520,7 @@
                                               mbedtls_md_type_t md_alg,
                                               const unsigned char *hash, size_t hlen,
                                               unsigned char *sig, size_t sig_size, size_t *slen,
-                                              int (*f_rng)(void *, unsigned char *, size_t),
+                                              mbedtls_f_rng_t *f_rng,
                                               void *p_rng,
                                               mbedtls_ecdsa_restart_ctx *rs_ctx);
 
@@ -608,7 +608,7 @@
  * \return         An \c MBEDTLS_ERR_ECP_XXX code on failure.
  */
 int mbedtls_ecdsa_genkey(mbedtls_ecdsa_context *ctx, mbedtls_ecp_group_id gid,
-                         int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
+                         mbedtls_f_rng_t *f_rng, void *p_rng);
 
 /**
  * \brief           This function sets up an ECDSA context from an EC key pair.