kdt/src/core/keys/privkey.rs

114 lines
3.7 KiB
Rust

// -- imports --
use serde::{
Deserialize,
Serialize,
};
use sha2::{
Digest,
Sha256,
};
use std::fmt;
// -- private key pair (signing key + crypto key) --
#[derive(Serialize, Deserialize, Clone)]
pub struct PrivKeyPair {
/// Base64-encoded bytes for private cryptographic
/// (ie Kyber) key.
pub crypto_key: String,
/// Base64-encoded bytes for private signage
/// (ie Dilithium) key.
pub signage_key: String,
/// Base64-encoded representation of the key
/// owner's name.
pub owner: String,
/// Sha256 hashsum of this object when the two
/// above values are set. On initialization, this is
/// `String::new()`, but a `PrivKeyPair::init()` call
/// generates it on-demand. Ids are very important for key
/// identification, so you should *always* call `PrivKeyPair::init()`
/// after `PrivKeyPair::new()`.
pub id: String,
}
impl PrivKeyPair {
/// Creates a new `PrivKeyPair` object from the provided cryptographic key
/// base64 string, the provided signage key string, and the owner base64
/// string. This doesn't validate the passed inputs, so it *will* panic if
/// you pass bad inputs.
pub fn new(crypto_key: String, signage_key: String, owner: String) -> Self {
Self {
crypto_key,
signage_key,
owner,
id: String::new(),
}
}
/// Computes a hash for the key pair, then sets the id as the hash. This
/// helps maintain distinctness between key ids.
#[inline(always)]
pub fn init(mut self) -> Self {
let mut hasher = Sha256::new();
hasher.update(self.to_string());
self.id = format!("{:X}", hasher.finalize());
self
}
/// Derives a `PrivKeyPair` object from the provided KDT private
/// key string. Doesn't validate input, so it *will* panic if you pass
/// invalid inputs.
pub fn from_str(privkey_str: String) -> Self {
let privkey: Vec<String> = privkey_str
.chars()
// Removes the `-----BEGIN KDT PRIVKEY BLOCK-----` header.
.skip(33)
// Removes the `-----END KDT PRIVKEY BLOCK-----` footer.
.take(privkey_str.len() - 33 - 32)
.collect::<String>()
// Turns the human-readable formatting to something that can be parsed
// programmatically.
.replace("\n", "")
// Splits the private key into a cryptographic key and signage key.
.split('*')
.map(String::from)
.collect();
Self {
crypto_key: privkey[0].to_owned(),
signage_key: privkey[1].to_owned(),
owner: privkey[2].to_owned(),
id: String::new(),
}
}
}
// -- human-readable key output impl --
impl fmt::Display for PrivKeyPair {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// An asterisk separates the encryption key from the
// signing key during key exchanges.
let keypair = format!("{}*{}*{}", &self.crypto_key, &self.signage_key, &self.owner)
.chars()
.enumerate()
// This helps maintain readability when printing messages. It
// inserts a new line at every nth (n = multiple of 64) character.
// This is identical to GPG's output style.
.flat_map(|(i, c)| {
if (i + 1) % 64 == 0 {
vec![c, '\n']
} else {
vec![c]
}
})
.collect::<String>();
write!(
f,
"-----BEGIN KDT PRIVKEY BLOCK-----\n{}\n-----END KDT PRIVKEY BLOCK-----",
keypair.trim_end()
)
}
}