# Module Netsys_crypto

    module Netsys_crypto: sig .. end

Cryptographic providers

Users should not call functions of the providers directly. Instead, use:

- `Netsys_tls` for using TLS
- `Netsys_ciphers` for using (symmetric) ciphers
- `Netsys_digests` for using digests

    val current_tls : unit -> (module Netsys_crypto_types.TLS_PROVIDER)

Return the current TLS provider. Only available if such a provider is linked into the executable. Do this by calling the `init` function of the provider, e.g. `Nettls_gnutls.init`.

    val current_tls_opt : unit -> (module Netsys_crypto_types.TLS_PROVIDER) option

Same as `current_tls` but it returns `None` if TLS is unavailable

    val current_symmetric_crypto : unit -> (module Netsys_crypto_types.SYMMETRIC_CRYPTO)

Returns the current provider for symmetric cryptography. This provider is always available, but may be empty (not implementing any ciphers).

    val current_digests : unit -> (module Netsys_crypto_types.DIGESTS)

Returns the current provider for cryptographic digests. This provider is always available, but may be empty (not implementing any digest).