-RAND_DRBG_new() and RAND_DRBG_secure_new()
-create a new DRBG instance of the given B<type>, allocated from the heap resp.
-the secure heap
-(using OPENSSL_zalloc() resp. OPENSSL_secure_zalloc()).
+RAND_DRBG_new_ex() creates a new DRBG instance of the given B<type> for the
+given OPENSSL_CTX <ctx>.
+The <ctx> parameter can be NULL in which case the default OPENSSL_CTX is used.
+RAND_DRBG_new() is the same as RAND_DRBG_new_ex() except that the default
+OPENSSL_CTX is always used.