结构体 CipherSuiteCommon 

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

密码套件的共享状态（及 TLS 1.2 和 TLS 1.3）

字段

suite: CipherSuite

此 TLS enumeration naming this cipher 套件）。

hash_provider: &'static dyn Hash

该密码包使用的哈希函数。

confidentiality_limit: u64

Number of TCP-TLS messages that can be safely encrypted with 一个 single key of this type

Once 一个 MessageEncrypter produced 用于 this suite has encrypted more than confidentiality_limit messages, an attacker gains an advantage in distinguishing it 从 an ideal pseudorandom permutation (PRP)。

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

For AES-GCM implementations, this should be set 到 2²⁴ 到 limit attack probability 到 one in 2⁶⁰。 ，请参见AEBounds (Table 1) 并 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

实现

impl CipherSuiteCommon

pub fn fips(&self) -> bool

Return true if this is 由 FIPS 批准的实现支持。

This means all the constituent parts that do cryptography return true 用于 fips()。