aerogramme/src/cryptoblob.rs
2023-05-15 18:23:23 +02:00

67 lines
2 KiB
Rust

//! Helper functions for secret-key encrypted blobs
//! that contain Zstd encrypted data
use anyhow::{anyhow, Result};
use serde::{Deserialize, Serialize};
use zstd::stream::{decode_all as zstd_decode, encode_all as zstd_encode};
//use sodiumoxide::crypto::box_ as publicbox;
use sodiumoxide::crypto::secretbox::xsalsa20poly1305 as secretbox;
pub use sodiumoxide::crypto::box_::{
gen_keypair, PublicKey, SecretKey, PUBLICKEYBYTES, SECRETKEYBYTES,
};
pub use sodiumoxide::crypto::secretbox::xsalsa20poly1305::{gen_key, Key, KEYBYTES};
pub fn open(cryptoblob: &[u8], key: &Key) -> Result<Vec<u8>> {
use secretbox::{Nonce, NONCEBYTES};
if cryptoblob.len() < NONCEBYTES {
return Err(anyhow!("Cyphertext too short"));
}
// Decrypt -> get Zstd data
let nonce = Nonce::from_slice(&cryptoblob[..NONCEBYTES]).unwrap();
let zstdblob = secretbox::open(&cryptoblob[NONCEBYTES..], &nonce, key)
.map_err(|_| anyhow!("Could not decrypt blob"))?;
// Decompress zstd data
let mut reader = &zstdblob[..];
let data = zstd_decode(&mut reader)?;
Ok(data)
}
pub fn seal(plainblob: &[u8], key: &Key) -> Result<Vec<u8>> {
use secretbox::{gen_nonce, NONCEBYTES};
// Compress data using zstd
let mut reader = plainblob;
let zstdblob = zstd_encode(&mut reader, 0)?;
// Encrypt
let nonce = gen_nonce();
let cryptoblob = secretbox::seal(&zstdblob, &nonce, key);
let mut res = Vec::with_capacity(NONCEBYTES + cryptoblob.len());
res.extend(nonce.as_ref());
res.extend(cryptoblob);
Ok(res)
}
pub fn open_deserialize<T: for<'de> Deserialize<'de>>(cryptoblob: &[u8], key: &Key) -> Result<T> {
let blob = open(cryptoblob, key)?;
Ok(rmp_serde::decode::from_read_ref::<_, T>(&blob)?)
}
pub fn seal_serialize<T: Serialize>(obj: T, key: &Key) -> Result<Vec<u8>> {
let mut wr = Vec::with_capacity(128);
let mut se = rmp_serde::Serializer::new(&mut wr)
.with_struct_map()
.with_string_variants();
obj.serialize(&mut se)?;
seal(&wr, key)
}