Keep an eye on this one: Botan in D, https://github.com/etcimon/botan
Should be finished in a couple weeks.
e.g. from the TLS module:
auto hmac = get_mac("HMAC(SHA-256)");
hmac.set_key(secret_key);
hmac.update_be(client_hello_bits.length);
hmac.update(client_hello_bits);
hmac.update_be(client_identity.length);
hmac.update(client_identity);
m_cookie = unlock(hmac.flush());
