crypto_box_keypair() is slow, because it involves with messaging. I think that functions implemented by salt_server was thread-unsafe. However now all libsodium functions are thread-safe[1], so I think that it's better to remove salt_server.
[1] https://github.com/jedisct1/libsodium/blob/master/src/libsodium/include/sodium/crypto_box.h
crypto_box_keypair() is slow, because it involves with messaging. I think that functions implemented by salt_server was thread-unsafe. However now all libsodium functions are thread-safe[1], so I think that it's better to remove salt_server.
[1] https://github.com/jedisct1/libsodium/blob/master/src/libsodium/include/sodium/crypto_box.h