-be used for generating long-term private keys. If using the default
-RAND_METHOD, this function uses a separate instance of the PRNG so that
-a compromise of the global generator will not affect such key generation.
+be used for generating values that should remain private. If using the
+default RAND_METHOD, this function uses a separate "private" PRNG
+instance so that a compromise of the "public" PRNG instance will not
+affect the secrecy of these private values, as described in L<RAND(7)>
+and L<RAND_DRBG(7)>.
+
+=head1 NOTES
+
+Always check the error return value of RAND_bytes() and
+RAND_priv_bytes() and do not take randomness for granted: an error occurs
+if the CSPRNG has not been seeded with enough randomness to ensure an
+unpredictable byte sequence.