ssh_packet/crypto/exchange.rs
1//! Facilities to produce some of the _exchange hashes_.
2
3use binrw::binwrite;
4
5use super::Lengthed;
6use crate::{arch, trans};
7
8/// The exchange hash for ECDH, computed as the
9/// hash of the concatenation of the following.
10///
11/// see <https://datatracker.ietf.org/doc/html/rfc5656#section-4>.
12#[binwrite]
13#[derive(Debug)]
14#[bw(big)]
15pub struct Ecdh<'b> {
16 /// Client's identification string (`\r` and `\n` excluded).
17 pub v_c: arch::Bytes<'b>,
18
19 /// Server's identification string (`\r` and `\n` excluded).
20 pub v_s: arch::Bytes<'b>,
21
22 /// Payload of the client's `SSH_MSG_KEXINIT` message.
23 pub i_c: Lengthed<&'b trans::KexInit<'b>>,
24
25 /// Payload of the server's `SSH_MSG_KEXINIT` message.
26 pub i_s: Lengthed<&'b trans::KexInit<'b>>,
27
28 /// Server's public host key.
29 pub k_s: arch::Bytes<'b>,
30
31 /// Client's ephemeral public key octet string.
32 pub q_c: arch::Bytes<'b>,
33
34 /// Server's ephemeral public key octet string.
35 pub q_s: arch::Bytes<'b>,
36
37 /// Computed shared secret.
38 pub k: arch::MpInt<'b>,
39}
40
41impl Ecdh<'_> {
42 /// Produce the exchange hash with the specified digest algorithm.
43 #[cfg(feature = "digest")]
44 #[cfg_attr(docsrs, doc(cfg(feature = "digest")))]
45 pub fn hash<D: digest::Digest>(&self) -> digest::Output<D> {
46 use binrw::BinWrite;
47
48 let mut buffer = Vec::new();
49 self.write(&mut std::io::Cursor::new(&mut buffer))
50 .expect("The binrw structure serialization failed");
51
52 D::digest(&buffer)
53 }
54}