Improve bls::SecretKey privacy (#1164)

* Improve bls::SecretKey privacy

* Add missed file

* Remove more methods from bls::SecretKey

* Add as_bytes() to SecretKey, remove as_raw

* Remove as_raw

* Add back as_raw

* Address review comments

common/validator_dir/Cargo.toml

@@ -17,8 +17,6 @@ eth2_keystore = { path = "../../crypto/eth2_keystore" }
 types = { path = "../../consensus/types" }
 rand = "0.7.2"
 deposit_contract = { path = "../deposit_contract" }
-eth2_ssz = { path = "../../consensus/ssz" }
-eth2_ssz_derive = { path = "../../consensus/ssz_derive" }
 rayon = "1.3.0"
 tree_hash = { path = "../../consensus/tree_hash" }
 

common/validator_dir/src/unencrypted_keys.rs

@@ -3,9 +3,8 @@
 //! we're confident that no-one is using these keypairs anymore (hopefully mid-June 2020).
 #![cfg(feature = "unencrypted_keys")]
 
+use bls::{BLS_PUBLIC_KEY_BYTE_SIZE as PK_LEN, BLS_SECRET_KEY_BYTE_SIZE as SK_LEN};
 use eth2_keystore::PlainText;
-use ssz::Decode;
-use ssz_derive::{Decode, Encode};
 use std::fs::File;
 use std::io::Read;
 use std::path::Path;
@@ -32,35 +31,18 @@ pub fn load_unencrypted_keypair<P: AsRef<Path>>(path: P) -> Result<Keypair, Stri
 
     let bytes: PlainText = bytes.into();
 
-    SszEncodableKeypair::from_ssz_bytes(bytes.as_bytes())
-        .map(Into::into)
-        .map_err(|e| format!("Unable to decode keypair: {:?}", e))
-}
-
-/// A helper struct to allow SSZ enc/dec for a `Keypair`.
-///
-/// This only exists as compatibility with the old scheme and should not be implemented on any new
-/// features.
-#[derive(Encode, Decode)]
-pub struct SszEncodableKeypair {
-    pk: PublicKey,
-    sk: SecretKey,
-}
-
-impl Into<Keypair> for SszEncodableKeypair {
-    fn into(self) -> Keypair {
-        Keypair {
-            sk: self.sk,
-            pk: self.pk,
-        }
+    if bytes.len() != PK_LEN + SK_LEN {
+        return Err(format!("Invalid keypair byte length: {}", bytes.len()));
     }
-}
 
-impl From<Keypair> for SszEncodableKeypair {
-    fn from(kp: Keypair) -> Self {
-        Self {
-            sk: kp.sk,
-            pk: kp.pk,
-        }
-    }
+    let pk_bytes = &bytes.as_bytes()[..PK_LEN];
+    let sk_bytes = &bytes.as_bytes()[PK_LEN..];
+
+    let pk = PublicKey::from_bytes(pk_bytes)
+        .map_err(|e| format!("Unable to decode public key: {:?}", e))?;
+
+    let sk = SecretKey::from_bytes(sk_bytes)
+        .map_err(|e| format!("Unable to decode secret key: {:?}", e))?;
+
+    Ok(Keypair { pk, sk })
 }

common/validator_dir/tests/tests.rs

@@ -118,7 +118,7 @@ impl Harness {
             check_keystore(&validator.dir().join(VOTING_KEYSTORE_FILE), &password_dir);
 
         if !config.random_voting_keystore {
-            assert_eq!(voting_keypair, generate_deterministic_keypair(0))
+            assert_eq!(voting_keypair.pk, generate_deterministic_keypair(0).pk)
         }
 
         // Use OR here instead of AND so we *always* check for the withdrawal keystores if random
@@ -128,11 +128,11 @@ impl Harness {
             let withdrawal_keypair = check_keystore(&withdrawal_keystore_path, &password_dir);
 
             if !config.random_withdrawal_keystore {
-                assert_eq!(withdrawal_keypair, generate_deterministic_keypair(1))
+                assert_eq!(withdrawal_keypair.pk, generate_deterministic_keypair(1).pk)
             }
 
             // The withdrawal keys should be distinct from the voting keypairs.
-            assert_ne!(withdrawal_keypair, voting_keypair);
+            assert_ne!(withdrawal_keypair.pk, voting_keypair.pk);
         }
 
         if !config.store_withdrawal_keystore && !config.random_withdrawal_keystore {