pub struct CryptoProvider {
    pub cipher_suites: Vec<SupportedCipherSuite>,
    pub kx_groups: Vec<&'static dyn SupportedKxGroup>,
    pub signature_verification_algorithms: WebPkiSupportedAlgorithms,
    pub secure_random: &'static dyn SecureRandom,
    pub key_provider: &'static dyn KeyProvider,
Expand description

Controls core cryptography used by rustls.

This crate comes with two built-in options, provided as CryptoProvider structures:

This structure provides defaults. Everything in it can be overridden at runtime by replacing field values as needed.

§Using the per-process default CryptoProvider

There is the concept of an implicit default provider, configured at run-time once in a given process.

It is used for functions like ClientConfig::builder() and ServerConfig::builder().

The intention is that an application can specify the CryptoProvider they wish to use once, and have that apply to the variety of places where their application does TLS (which may be wrapped inside other libraries). They should do this by calling CryptoProvider::install_default() early on.

To achieve this goal:

§Using a specific CryptoProvider

Supply the provider when constructing your ClientConfig or ServerConfig:

When creating and configuring a webpki-backed client or server certificate verifier, a choice of provider is also needed to start the configuration process:

§Making a custom CryptoProvider

Your goal will be to populate a crypto::CryptoProvider struct instance.

§Which elements are required?

There is no requirement that the individual elements (SupportedCipherSuite, SupportedKxGroup, SigningKey, etc.) come from the same crate. It is allowed and expected that uninteresting elements would be delegated back to one of the default providers (statically) or a parent provider (dynamically).

For example, if we want to make a provider that just overrides key loading in the config builder API (ConfigBuilder::with_single_cert etc.), it might look like this:

use rustls::crypto::aws_lc_rs;

pub fn provider() -> rustls::crypto::CryptoProvider {
    key_provider: &HsmKeyLoader,

struct HsmKeyLoader;

impl rustls::crypto::KeyProvider for HsmKeyLoader {
    fn load_private_key(&self, key_der: pki_types::PrivateKeyDer<'static>) -> Result<Arc<dyn rustls::sign::SigningKey>, rustls::Error> {

§References to the individual elements

The elements are documented separately:

§Example code

See provider-example/ for a full client and server example that uses cryptography from the rust-crypto and dalek-cryptography projects.

$ cargo run --example client | head -3
Current ciphersuite: TLS13_CHACHA20_POLY1305_SHA256
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 19899

§FIPS-approved cryptography

The fips crate feature enables use of the aws-lc-rs crate in FIPS mode.

You can verify the configuration at runtime by checking ServerConfig::fips()/ClientConfig::fips() return true.


§cipher_suites: Vec<SupportedCipherSuite>

List of supported ciphersuites, in preference order – the first element is the highest priority.

The SupportedCipherSuite type carries both configuration and implementation.

A valid CryptoProvider must ensure that all cipher suites are accompanied by at least one matching key exchange group in CryptoProvider::kx_groups.

§kx_groups: Vec<&'static dyn SupportedKxGroup>

List of supported key exchange groups, in preference order – the first element is the highest priority.

The first element in this list is the default key share algorithm, and in TLS1.3 a key share for it is sent in the client hello.

The SupportedKxGroup type carries both configuration and implementation.

§signature_verification_algorithms: WebPkiSupportedAlgorithms

List of signature verification algorithms for use with webpki.

These are used for both certificate chain verification and handshake signature verification.

This is called by ConfigBuilder::with_root_certificates(), server::WebPkiClientVerifier::builder_with_provider() and client::WebPkiServerVerifier::builder_with_provider().

§secure_random: &'static dyn SecureRandom

Source of cryptographically secure random numbers.

§key_provider: &'static dyn KeyProvider

Provider for loading private SigningKeys from PrivateKeyDer.



impl CryptoProvider


pub fn install_default(self) -> Result<(), Arc<Self>>

Available on crate feature std only.

Sets this CryptoProvider as the default for this process.

This can be called successfully at most once in any process execution.

Call this early in your process to configure which provider is used for the provider. The configuration should happen before any use of ClientConfig::builder() or ServerConfig::builder().


pub fn get_default() -> Option<&'static Arc<Self>>

Returns the default CryptoProvider for this process.

This will be None if no default has been set yet.


pub fn fips(&self) -> bool

Returns true if this CryptoProvider is operating in FIPS mode.

This covers only the cryptographic parts of FIPS approval. There are also TLS protocol-level recommendations made by NIST. You should prefer to call ClientConfig::fips() or ServerConfig::fips() which take these into account.

Trait Implementations§


impl Clone for CryptoProvider


fn clone(&self) -> CryptoProvider

Returns a copy of the value. Read more
1.0.0 · source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more

impl Debug for CryptoProvider


fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

Auto Trait Implementations§

Blanket Implementations§


impl<T> Any for T
where T: 'static + ?Sized,


fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

impl<T> Borrow<T> for T
where T: ?Sized,


fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

impl<T> BorrowMut<T> for T
where T: ?Sized,


fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

impl<T> From<T> for T


fn from(t: T) -> T

Returns the argument unchanged.


impl<T, U> Into<U> for T
where U: From<T>,


fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.


impl<T> ToOwned for T
where T: Clone,


type Owned = T

The resulting type after obtaining ownership.

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more

impl<T, U> TryFrom<U> for T
where U: Into<T>,


type Error = Infallible

The type returned in the event of a conversion error.

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,


type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.