With the help of rustler you can use Rust to decrypt the AES key. I used the node.js example and was able to decode the encrypted AES key using Rust/Rustler:
use base64::prelude::*;
use rustler::{Env, NifResult};
use rsa::{RsaPrivateKey, Oaep, sha2::Sha256};
use rsa::pkcs8::DecodePrivateKey;
use rustler::types::binary::{Binary, OwnedBinary};
#[rustler::nif(schedule = "DirtyCpu")]
fn decrypt<'a>(env: Env<'a>, private_file_path: String, cipher_text: String) -> NifResult<Binary<'a>> {
let padding = Oaep::new::<Sha256>();
let content = std::fs::read_to_string(&private_file_path).unwrap();
let private_key = RsaPrivateKey::from_pkcs8_pem(&content).unwrap();
let enc_data = BASE64_STANDARD.decode(cipher_text).unwrap();
let dec_data = private_key.decrypt(padding, &enc_data).unwrap();
let mut result: OwnedBinary = OwnedBinary::new(dec_data.len()).unwrap();
result.as_mut_slice().copy_from_slice(&dec_data);
Ok(Binary::from_owned(result, env))
}
rustler::init!("Elixir.RCrypto");
Here is the output:
iex [09:40 :: 2] > RCrypto.decrypt("./private_unencrypted.pem", "hiHNE0AFZI6pn/Sbo0yPmbm37NQxuCc1rDxotfkeOHjjCO9BEVMtLQKfOE6w2/VQwISqJpAE0D9FlScvEdMgNjtbo5rNRutHFVF5xnvLsXyV228dxt5m8h+6k1LApk5TLOj97+fi4iiYq5Tr3n1E+4jpY0TTl30s/k0rhciOIy7HwFpaRWVSiOZFqx+PTYrJYcRot/DoArd4DLAdlbeoHcyoB4R0LV4DJRUmKwrcP/7J3njC1PpetGjgGiy5g/e/dKoxmcjjyhSwS7QeoCxBAF4ErHWHFfNOeNyCdwLmOtlLIa55nwGQ0Jyn0xp4WQj2xJqoHvCTcqbAxRtCJ5b5zA==")
"<some-key-data>"
iex [09:40 :: 3] >
Of course, the code is just a quick demo. Loading the key for each call should not be used at all.
