Considering the following OpenVPN (2.4) option from the manual:
--prng alg [nsl] (Advanced) For PRNG (Pseudo-random number generator), use digest algorithm alg (default=sha1), and set nsl (default=16) to the size in bytes of the nonce secret length (between 16 and 64). Set alg=none to disable the PRNG and use the OpenSSL RAND_bytes function instead for all of OpenVPN's pseudo-random number needs.
How much would the entropy of the prng be increased by a more secure hashing algorithm, say
Also, what exactly is the
nonce secret length and how does it impact the entropy?