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Module _04_features

rustls::manual

Module _04_features 

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本节说明 rustls 本身：哪些协议功能已实现、哪些未实现

此 below list reflects the support provided with 默认 crate features. Items marked with an asterisk * can be extended 或 altered via public APIs (CryptoProvider 用于 example)。

§Current features

  • TLS1.2 and TLS1.3
  • ECDSA, Ed25519 or RSA server authentication by clients *
  • ECDSA, Ed255191 or RSA server authentication by servers *
  • Forward secrecy using ECDHE; with curve25519, nistp256 or nistp384 curves *
  • Post-quantum hybrid key exchange with X25519MLKEM768 2 *
  • AES128-GCM and AES256-GCM bulk encryption, with safe nonces *
  • ChaCha20-Poly1305 bulk encryption (RFC7905) *
  • ALPN support
  • SNI support
  • Tunable fragment size to make TLS messages match size of underlying transport
  • Optional use of vectored IO to minimise system calls
  • TLS1.2 session resumption
  • TLS1.2 resumption via tickets (RFC5077)
  • TLS1.3 resumption via tickets or session storage
  • TLS1.3 0-RTT data
  • Server and optional client authentication
  • Extended master secret support (RFC7627)
  • Exporters (RFC5705)
  • OCSP stapling by servers
  • RFC7250 raw public keys for TLS1.3
  • RFC8879 certificate compression by clients and servers *
  • Client-side Encrypted client hello (ECH) (draft-ietf-tls-esni).

§Non-features

For reasons explained in the other sections of this manual, rustls does not 并 will not support:

  • SSL1, SSL2, SSL3, TLS1 or TLS1.1
  • RC4
  • DES or triple DES
  • EXPORT ciphersuites
  • MAC-then-encrypt ciphersuites
  • Ciphersuites without forward secrecy
  • Renegotiation
  • Kerberos
  • TLS 1.2 protocol compression
  • Discrete-log Diffie-Hellman *
  • Automatic protocol version downgrade
  • Using CA certificates directly to authenticate a server/client (often called “self-signed certificates”). Rustls’ default certificate verifier does not support using a trust anchor as both a CA certificate and an end-entity certificate in order to limit complexity and risk in path building. While dangerous, all authentication can be turned off if required – see the example code *

§About “custom extensions”

OpenSSL allows an application 到 add arbitrary TLS extensions (via the SSL_CTX_add_custom_ext function 并 associated APIs)。 We don’t support this, with the following rationale:

Such an API is limited 到 extensions that are quite narrow in scope: they cannot change the meaning of 标准 messages, 或 introduce new messages, 或 make any changes 到 the connection’s cryptography.

However, there is no reasonable way 到 technically limit that API 到 that set of extensions. That makes the API pretty unsafe (in the TLS 并 cryptography sense, not memory safety sense)。 This could cause security 或 interop failures.

我们建议该 API 的潜在使用者考虑：

  • whether their use can fit in standard extensions such as ALPN, or ALPS3.
  • if not, whether they can fit in a more general extension, and define and standardize that in the IETF TLSWG.

Note the above is not 一个 guarantee 或 offer that rustls will implement any specific extensions that are standardized by the IETF TLSWG. It 是 non-goal of this project 到 implement absolutely everything.

For experimentation 并 pre-standardization testing, we suggest forking rustls.

参见：Go 对这种 API 的立场。

  1. Note that, at the time of writing, Ed25519 does not have wide support in browsers. It 也 not supported by the WebPKI, because the CA/Browser Forum Baseline Requirements do not support it 用于 publicly trusted 证书 ↩

  2. ，请参见the documentation ↩

  3. rustls does not currently implement ALPS, but it is something we would consider once standardised 并 deployed. ↩