Struct rustls::crypto::CipherSuiteCommon

pub struct CipherSuiteCommon {
    pub suite: CipherSuite,
    pub hash_provider: &'static dyn Hash,
    pub confidentiality_limit: u64,
}

Common state for cipher suites (both for TLS 1.2 and TLS 1.3)

Fields

suite: CipherSuite

The TLS enumeration naming this cipher suite.

hash_provider: &'static dyn Hash

Which hash function the suite uses.

confidentiality_limit: u64

Number of TCP-TLS messages that can be safely encrypted with a single key of this type

Once a MessageEncrypter produced for this suite has encrypted more than confidentiality_limit messages, an attacker gains an advantage in distinguishing it from an ideal pseudorandom permutation (PRP).

This is to be set on the assumption that messages are maximally sized – each is 2¹⁴ bytes. It does not consider confidentiality limits for QUIC connections - see the [quic::KeyBuilder.confidentiality_limit] field for this context.

For AES-GCM implementations, this should be set to 2²⁴ to limit attack probability to one in 2⁶⁰. See AEBounds (Table 1) and draft-irtf-aead-limits-08:

>>> p = 2 ** -60
>>> L = (2 ** 14 // 16) + 1
>>> qlim = (math.sqrt(p) * (2 ** (129 // 2)) - 1) / (L + 1)
>>> print(int(qlim).bit_length())
24

For chacha20-poly1305 implementations, this should be set to u64::MAX: see https://www.ietf.org/archive/id/draft-irtf-cfrg-aead-limits-08.html#section-5.2.1

Implementations

impl CipherSuiteCommon

pub fn fips(&self) -> bool

Return true if this is backed by a FIPS-approved implementation.

This means all the constituent parts that do cryptography return true for fips().

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes