diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index c1e76b3..3f0881a 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -465,7 +465,7 @@
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_gen_key(mbedtls_rsa_context *ctx,
-                        int (*f_rng)(void *, unsigned char *, size_t),
+                        mbedtls_f_rng_t *f_rng,
                         void *p_rng,
                         unsigned int nbits, int exponent);
 
@@ -590,7 +590,7 @@
  *
  */
 int mbedtls_rsa_private(mbedtls_rsa_context *ctx,
-                        int (*f_rng)(void *, unsigned char *, size_t),
+                        mbedtls_f_rng_t *f_rng,
                         void *p_rng,
                         const unsigned char *input,
                         unsigned char *output);
@@ -619,7 +619,7 @@
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_pkcs1_encrypt(mbedtls_rsa_context *ctx,
-                              int (*f_rng)(void *, unsigned char *, size_t),
+                              mbedtls_f_rng_t *f_rng,
                               void *p_rng,
                               size_t ilen,
                               const unsigned char *input,
@@ -646,7 +646,7 @@
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_rsaes_pkcs1_v15_encrypt(mbedtls_rsa_context *ctx,
-                                        int (*f_rng)(void *, unsigned char *, size_t),
+                                        mbedtls_f_rng_t *f_rng,
                                         void *p_rng,
                                         size_t ilen,
                                         const unsigned char *input,
@@ -680,7 +680,7 @@
  * \return           An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_rsaes_oaep_encrypt(mbedtls_rsa_context *ctx,
-                                   int (*f_rng)(void *, unsigned char *, size_t),
+                                   mbedtls_f_rng_t *f_rng,
                                    void *p_rng,
                                    const unsigned char *label, size_t label_len,
                                    size_t ilen,
@@ -723,7 +723,7 @@
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_pkcs1_decrypt(mbedtls_rsa_context *ctx,
-                              int (*f_rng)(void *, unsigned char *, size_t),
+                              mbedtls_f_rng_t *f_rng,
                               void *p_rng,
                               size_t *olen,
                               const unsigned char *input,
@@ -765,7 +765,7 @@
  *
  */
 int mbedtls_rsa_rsaes_pkcs1_v15_decrypt(mbedtls_rsa_context *ctx,
-                                        int (*f_rng)(void *, unsigned char *, size_t),
+                                        mbedtls_f_rng_t *f_rng,
                                         void *p_rng,
                                         size_t *olen,
                                         const unsigned char *input,
@@ -806,7 +806,7 @@
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_rsaes_oaep_decrypt(mbedtls_rsa_context *ctx,
-                                   int (*f_rng)(void *, unsigned char *, size_t),
+                                   mbedtls_f_rng_t *f_rng,
                                    void *p_rng,
                                    const unsigned char *label, size_t label_len,
                                    size_t *olen,
@@ -849,7 +849,7 @@
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_pkcs1_sign(mbedtls_rsa_context *ctx,
-                           int (*f_rng)(void *, unsigned char *, size_t),
+                           mbedtls_f_rng_t *f_rng,
                            void *p_rng,
                            mbedtls_md_type_t md_alg,
                            unsigned int hashlen,
@@ -881,7 +881,7 @@
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_rsassa_pkcs1_v15_sign(mbedtls_rsa_context *ctx,
-                                      int (*f_rng)(void *, unsigned char *, size_t),
+                                      mbedtls_f_rng_t *f_rng,
                                       void *p_rng,
                                       mbedtls_md_type_t md_alg,
                                       unsigned int hashlen,
@@ -933,7 +933,7 @@
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_rsassa_pss_sign_ext(mbedtls_rsa_context *ctx,
-                                    int (*f_rng)(void *, unsigned char *, size_t),
+                                    mbedtls_f_rng_t *f_rng,
                                     void *p_rng,
                                     mbedtls_md_type_t md_alg,
                                     unsigned int hashlen,
@@ -983,7 +983,7 @@
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
  */
 int mbedtls_rsa_rsassa_pss_sign(mbedtls_rsa_context *ctx,
-                                int (*f_rng)(void *, unsigned char *, size_t),
+                                mbedtls_f_rng_t *f_rng,
                                 void *p_rng,
                                 mbedtls_md_type_t md_alg,
                                 unsigned int hashlen,