Database encryption key backup / recovery feature for entropy-tss

CHANGELOG.md

@@ -50,6 +50,7 @@ runtime
 - Test CLI command to retrieve quote and change endpoint / TSS account in one command ([#1198](https://github.com/entropyxyz/entropy-core/pull/1198))
 - On-chain unresponsiveness reporting [(#1215)](https://github.com/entropyxyz/entropy-core/pull/1215)
 - Add cli options for adding validator [(#1242)](https://github.com/entropyxyz/entropy-core/pull/1242)
+- Database encryption key backup / recovery feature for entropy-tss [(#1249)](https://github.com/entropyxyz/entropy-core/pull/1249)
 
 ### Changed
 - Use correct key rotation endpoint in OCW ([#1104](https://github.com/entropyxyz/entropy-core/pull/1104))

crates/client/src/client.rs

@@ -50,7 +50,7 @@ pub use crate::{
     errors::{ClientError, SubstrateError},
 };
 pub use entropy_protocol::{sign_and_encrypt::EncryptedSignedMessage, KeyParams};
-pub use entropy_shared::{HashingAlgorithm, QuoteContext};
+pub use entropy_shared::{attestation::QuoteContext, HashingAlgorithm};
 use parity_scale_codec::Decode;
 use rand::Rng;
 use std::str::FromStr;

crates/client/src/tests.rs

@@ -19,7 +19,7 @@ use crate::{
     update_programs,
 };
 
-use entropy_shared::{QuoteContext, QuoteInputData};
+use entropy_shared::attestation::{QuoteContext, QuoteInputData};
 use entropy_testing_utils::{
     constants::{TEST_PROGRAM_WASM_BYTECODE, TSS_ACCOUNTS, X25519_PUBLIC_KEYS},
     helpers::{encode_verifying_key, spawn_tss_nodes_and_start_chain},
@@ -129,7 +129,7 @@ async fn test_change_threshold_accounts() {
     let encoded_pck = encode_verifying_key(&pck.verifying_key()).unwrap().to_vec();
 
     let quote = {
-        let input_data = entropy_shared::QuoteInputData::new(
+        let input_data = QuoteInputData::new(
             tss_public_key,
             *x25519_public_key.as_bytes(),
             nonce,
@@ -368,7 +368,7 @@ async fn test_set_session_key_and_declare_validate() {
     let encoded_pck = encode_verifying_key(&pck.verifying_key()).unwrap().to_vec();
 
     let quote = {
-        let input_data = entropy_shared::QuoteInputData::new(
+        let input_data = QuoteInputData::new(
             tss_public_key,
             *x25519_public_key.as_bytes(),
             nonce,

crates/kvdb/src/encrypted_sled/constants.rs

@@ -16,5 +16,3 @@
 //! Constants for [encrypted_sled](crate::encrypted_sled)
 pub(super) const PASSWORD_VERIFICATION_KEY: &str = "verification_key";
 pub(super) const PASSWORD_VERIFICATION_VALUE: &str = "verification_value";
-pub(super) const PASSWORD_SALT_KEY: &[u8] = b"password_salt_key";
-pub(super) const UNSAFE_PASSWORD: &str = "entropy_unsafe_password";

crates/kvdb/src/encrypted_sled/kv.rs

@@ -19,8 +19,6 @@
 //! to be inserted, forming a [EncryptedRecord]:<encrypted value, nonce>. The nonce is later
 //! used to decrypt and retrieve the originally inserted value.
 
-use std::convert::TryInto;
-
 use chacha20poly1305::{
     self,
     aead::{AeadInPlace, NewAead},
@@ -32,7 +30,6 @@ use zeroize::Zeroize;
 
 use super::{
     constants::*,
-    password::{Password, PasswordSalt},
     record::EncryptedRecord,
     result::{EncryptedDbError::*, EncryptedDbResult},
 };
@@ -48,26 +45,13 @@ impl EncryptedDb {
     /// Creates an XChaCha20 stream cipher from a password-based-key-derivation-function and
     /// verifies that the password is valid.
     /// See [super::Password] for more info on pdkdf.
-    pub fn open<P>(db_name: P, password: Password) -> EncryptedDbResult<Self>
+    pub fn open<P>(db_name: P, mut key: [u8; 32]) -> EncryptedDbResult<Self>
     where
         P: AsRef<std::path::Path>,
     {
         let kv = sled::open(db_name).map_err(CorruptedKv)?;
 
-        let password_salt: PasswordSalt = if kv.was_recovered() {
-            // existing kv: get the existing password salt
-            kv.get(PASSWORD_SALT_KEY)?.ok_or(MissingPasswordSalt)?.try_into()?
-        } else {
-            // new kv: choose a new password salt and store it
-            let mut password_salt = [0u8; 32];
-            rand::thread_rng().fill_bytes(&mut password_salt);
-            kv.insert(PASSWORD_SALT_KEY, &password_salt)?;
-            password_salt.into()
-        };
-
-        // zeroize key since we are no longer using it after creating cipher
-        let mut key = Self::chacha20poly1305_kdf(password, password_salt)?;
-        let cipher = XChaCha20Poly1305::new(&key);
+        let cipher = XChaCha20Poly1305::new(&key.into());
         key.zeroize();
 
         let encrypted_db = EncryptedDb { kv, cipher };
@@ -84,23 +68,6 @@ impl EncryptedDb {
         Ok(encrypted_db)
     }
 
-    fn chacha20poly1305_kdf(
-        password: Password,
-        salt: PasswordSalt,
-    ) -> EncryptedDbResult<chacha20poly1305::Key> {
-        let mut output = chacha20poly1305::Key::default();
-
-        // default params: log_n = 15, r = 8, p = 1
-        scrypt::scrypt(
-            password.as_ref(),
-            salt.as_ref(),
-            &scrypt::Params::default(),
-            output.as_mut_slice(),
-        )?;
-
-        Ok(output)
-    }
-
     /// get a new random nonce to use for value encryption using [rand::thread_rng]
     fn generate_nonce() -> chacha20poly1305::XNonce {
         let mut bytes = chacha20poly1305::XNonce::default();

crates/kvdb/src/encrypted_sled/mod.rs

@@ -20,17 +20,12 @@
 
 mod constants;
 mod kv;
-mod password;
 mod record;
 mod result;
 
 // match the API of sled
 pub use kv::EncryptedDb as Db;
-pub use password::{Password, PasswordMethod, PasswordSalt};
 pub use result::{EncryptedDbError as Error, EncryptedDbResult as Result};
 
 #[cfg(test)]
 mod tests;
-
-#[cfg(test)]
-pub use tests::get_test_password;

crates/kvdb/src/encrypted_sled/tests.rs

@@ -15,23 +15,17 @@
 
 use serial_test::serial;
 
-use super::{kv::EncryptedDb, Password};
+use super::kv::EncryptedDb;
 use crate::{clean_tests, encrypted_sled::Db, get_db_path};
 
-fn setup_db(require_password: bool) -> Db {
-    let db = if !require_password {
-        EncryptedDb::open(get_db_path(true), get_test_password())
-    } else {
-        EncryptedDb::open(get_db_path(true), Password::from("super-secret password."))
-    };
-    assert!(db.is_ok());
-    db.unwrap()
+fn setup_db(key: [u8; 32]) -> Db {
+    EncryptedDb::open(get_db_path(true), key).unwrap()
 }
 
 #[test]
 #[serial]
 fn test_encrypted_sled() {
-    let db = setup_db(false);
+    let db = setup_db([1; 32]);
 
     // insert <key: value> -> returns None
     let res = db.insert("key", "value").unwrap();
@@ -73,36 +67,33 @@ fn test_encrypted_sled() {
 
 #[test]
 #[serial]
-fn test_use_existing_salt() {
-    let db = setup_db(false);
+fn test_use_existing_key() {
+    let db = setup_db([1; 32]);
     let db_path = get_db_path(true);
     drop(db);
     // open existing db
-    assert!(EncryptedDb::open(db_path, get_test_password()).is_ok());
+    assert!(EncryptedDb::open(db_path, [1; 32]).is_ok());
     clean_tests();
 }
 
 #[test]
 #[serial]
-fn test_password() {
-    let db = setup_db(true);
+fn test_key() {
+    let db = setup_db([1; 32]);
     let db_path = get_db_path(true);
 
     drop(db);
 
-    // try to open the kv store using a different password
-    let db = EncryptedDb::open(
-        db_path,
-        Password::from("super-secret password!"), // replace '.' with '!'
-    );
+    // try to open the kv store using a different key
+    let db = EncryptedDb::open(db_path, [2; 32]);
     assert!(matches!(db, Err(super::result::EncryptedDbError::WrongPassword)));
     clean_tests();
 }
 
 #[test]
 #[serial]
 fn test_large_input() {
-    let db = setup_db(false);
+    let db = setup_db([1; 32]);
 
     let large_value = vec![0; 100000];
     let res = db.insert("key", large_value.clone()).unwrap();
@@ -112,7 +103,3 @@ fn test_large_input() {
     assert_eq!(res, Some(sled::IVec::from(large_value)));
     clean_tests();
 }
-
-pub fn get_test_password() -> Password {
-    crate::encrypted_sled::PasswordMethod::NoPassword.execute().unwrap()
-}

crates/kvdb/src/kv_manager/kv.rs

@@ -29,7 +29,7 @@ use super::{
         KeyReservation, DEFAULT_KV_NAME, DEFAULT_KV_PATH,
     },
 };
-use crate::encrypted_sled::{self, Password};
+use crate::encrypted_sled;
 
 #[derive(Clone)]
 pub struct Kv<V> {
@@ -44,22 +44,22 @@ where
 {
     /// Creates a new kv service. Returns [InitErr] on failure.
     /// the path of the kvstore is `root_path` + "/kvstore/" + `kv_name`
-    pub fn new(root_path: PathBuf, password: Password) -> KvResult<Self> {
+    pub fn new(root_path: PathBuf, key: [u8; 32]) -> KvResult<Self> {
         let kv_path = root_path.join(DEFAULT_KV_PATH).join(DEFAULT_KV_NAME);
         // use to_string_lossy() instead of to_str() to avoid handling Option<&str>
         let kv_path = kv_path.to_string_lossy().to_string();
-        Self::with_db_name(kv_path, password)
+        Self::with_db_name(kv_path, key)
     }
 
     /// Creates a kvstore at `full_db_name` and spawns a new kv_manager. Returns [InitErr] on
     /// failure. `full_db_name` is the name of the path of the kvstrore + its name
     /// Example: ~/entropy/kvstore/database_1
-    pub fn with_db_name(full_db_name: String, password: Password) -> KvResult<Self> {
+    pub fn with_db_name(full_db_name: String, encryption_key: [u8; 32]) -> KvResult<Self> {
         let (sender, rx) = mpsc::unbounded_channel();
 
         // get kv store from db name before entering the kv_cmd_handler because
         // it's more convenient to return an error from outside of a tokio::span
-        let kv = get_kv_store(&full_db_name, password)?;
+        let kv = get_kv_store(&full_db_name, encryption_key)?;
 
         tokio::spawn(kv_cmd_handler(rx, kv));
         Ok(Self { sender })
@@ -129,13 +129,10 @@ where
 ///  let my_db = get_kv_store(&"my_current_dir_db")?;
 ///  let my_db = get_kv_store(&"/tmp/my_tmp_bd")?;
 #[tracing::instrument(skip_all, fields(db_name))]
-pub fn get_kv_store(
-    db_name: &str,
-    password: Password,
-) -> encrypted_sled::Result<encrypted_sled::Db> {
+pub fn get_kv_store(db_name: &str, key: [u8; 32]) -> encrypted_sled::Result<encrypted_sled::Db> {
     // create/open DB
     tracing::debug!("Decrypting KV store");
-    let kv = encrypted_sled::Db::open(db_name, password)?;
+    let kv = encrypted_sled::Db::open(db_name, key)?;
 
     // log whether the DB was newly created or not
     if kv.was_recovered() {