Use WnafBase and WnafScalar for Migration Cred

src/migration_table.rs

@@ -8,31 +8,28 @@ that the credentials contain the bucket attributes, which include both
 the id and the bucket decryption key, but the table just contains the
 bucket ids.) */
 
-#[cfg(feature = "bridgeauth")]
-use cmz::CMZPrivkey;
-use cmz::{CMZCredential, CMZPubkey};
+use cmz::*;
 use curve25519_dalek::ristretto::CompressedRistretto;
-#[cfg(feature = "bridgeauth")]
-use curve25519_dalek::ristretto::RistrettoBasepointTable;
-use curve25519_dalek::ristretto::RistrettoPoint as G;
-use curve25519_dalek::scalar::Scalar;
-
-use sha2::Digest;
-use sha2::Sha256;
-
+//#[cfg(feature = "bridgeauth")]
 use aes_gcm::aead::{generic_array::GenericArray, Aead};
 use aes_gcm::{Aes128Gcm, KeyInit};
-#[cfg(feature = "bridgeauth")]
+use ff::PrimeField;
+use group::{WnafBase, WnafScalar};
+use sha2::Digest;
+use sha2::Sha256;
+//#[cfg(feature = "bridgeauth")]
 use rand::RngCore;
 
 use std::collections::HashMap;
 
-#[cfg(feature = "bridgeauth")]
-use serde::{Deserialize, Serialize};
-
+//#[cfg(feature = "bridgeauth")]
 #[cfg(feature = "bridgeauth")]
 use super::bridge_table;
 use super::lox_creds::{Migration, MigrationKey};
+use super::{Scalar, G};
+use serde::{Deserialize, Serialize};
+
+pub const WNAF_SIZE: usize = 6;
 
 /// Each (plaintext) entry in the returned migration table is serialized
 /// into this many bytes
@@ -51,7 +48,7 @@ pub enum MigrationType {
     Blockage,
 }
 
-impl From<MigrationType> for Scalar {
+impl From<MigrationType> for u128 {
     /// Convert a MigrationType into the Scalar value that represents
     /// it in the Migration credential
     fn from(m: MigrationType) -> Self {
@@ -65,7 +62,7 @@ impl From<MigrationType> for Scalar {
 
 /// The migration table
 #[derive(Default, Debug, Serialize, Deserialize)]
-#[cfg(feature = "bridgeauth")]
+//#[cfg(feature = "bridgeauth")]
 pub struct MigrationTable {
     pub table: HashMap<u32, u32>,
     pub migration_type: Scalar,
@@ -83,13 +80,13 @@ pub struct MigrationTable {
 /// from_attr_i, Qk_i) and the encrypted Migration credential.  H1 and
 /// H2 are the first 16 bytes and the second 16 bytes respectively of
 /// the SHA256 hash of the input.
-#[cfg(feature = "bridgeauth")]
+//#[cfg(feature = "bridgeauth")]
 pub fn encrypt_cred(
     id: Scalar,
     from_bucket: Scalar,
     to_bucket: Scalar,
     migration_type: Scalar,
-    Pktable: &RistrettoBasepointTable,
+    Pktable: &WnafBase<G, WNAF_SIZE>,
     migration_priv: &CMZPrivkey<G>,
     migrationkey_priv: &CMZPrivkey<G>,
 ) -> ([u8; 16], [u8; ENC_MIGRATION_BYTES]) {
@@ -100,10 +97,8 @@ pub fn encrypt_cred(
     let mut K = MigrationKey::using_privkey(migrationkey_priv);
     K.lox_id = Some(id);
     K.from_bucket = Some(from_bucket);
-    K.MAC.Q = &(migrationkey_priv.x[0]
-        + migrationkey_priv.x[1] * id
-        + migrationkey_priv.x[2] * from_bucket)
-        * Pktable;
+    let coeff: Scalar = K.compute_MAC_coeff(&migrationkey_priv).unwrap();
+    K.MAC.Q = Pktable * &WnafScalar::new(&coeff);
 
     // Compute a MAC (P, Q) on the Migration credential
     let mut M = Migration::using_privkey(migration_priv);
@@ -111,7 +106,7 @@ pub fn encrypt_cred(
     M.from_bucket = Some(from_bucket);
     M.to_bucket = Some(to_bucket);
     M.migration_type = Some(migration_type);
-    // let b = Scalar::random(&mut rng);
+    let _ = M.create_MAC(&mut rng, migration_priv);
 
     // Serialize (to_bucket, P, Q)
     let mut credbytes: [u8; MIGRATION_BYTES] = [0; MIGRATION_BYTES];
@@ -162,7 +157,7 @@ pub fn encrypt_cred_ids(
     to_id: u32,
     migration_type: Scalar,
     bridgetable: &bridge_table::BridgeTable,
-    Pktable: &RistrettoBasepointTable,
+    Pktable: &WnafBase<G, WNAF_SIZE>,
     migration_priv: &CMZPrivkey<G>,
     migrationkey_priv: &CMZPrivkey<G>,
 ) -> Option<([u8; 16], [u8; ENC_MIGRATION_BYTES])> {
@@ -186,7 +181,7 @@ impl MigrationTable {
     pub fn new(table_type: MigrationType) -> Self {
         Self {
             table: Default::default(),
-            migration_type: table_type.into(),
+            migration_type: Scalar::from_u128(table_type.into()),
         }
     }
 
@@ -197,7 +192,7 @@ impl MigrationTable {
         &self,
         id: Scalar,
         bridgetable: &bridge_table::BridgeTable,
-        Pktable: &RistrettoBasepointTable,
+        Pktable: &WnafBase<G, WNAF_SIZE>,
         migration_priv: &CMZPrivkey<G>,
         migrationkey_priv: &CMZPrivkey<G>,
     ) -> HashMap<[u8; 16], [u8; ENC_MIGRATION_BYTES]> {
@@ -272,6 +267,6 @@ pub fn decrypt_cred(
     M.lox_id = mk_cred.lox_id;
     M.from_bucket = mk_cred.from_bucket;
     M.to_bucket = Some(to_bucket);
-    M.migration_type = Some(migration_type.into());
+    M.migration_type = Some(Scalar::from_u128(migration_type.into()));
     Some(M)
 }

src/proto/check_blockage.rs

@@ -39,9 +39,8 @@ use crate::migration_table;
 use crate::migration_table::ENC_MIGRATION_BYTES;
 use cmz::*;
 #[cfg(feature = "bridgeauth")]
-use curve25519_dalek::ristretto::RistrettoBasepointTable;
 use curve25519_dalek::ristretto::RistrettoPoint as G;
-use group::Group;
+use group::{Group, WnafBase};
 use rand_core::RngCore;
 use sha2::Sha512;
 use std::collections::HashMap;
@@ -137,7 +136,7 @@ impl BridgeAuth {
             },
         ) {
             Ok((response, (L_issuer, M_issuer))) => {
-                let Pktable = RistrettoBasepointTable::create(&M_issuer.MAC.P);
+                let Pktable: WnafBase<G, WNAF_SIZE> = WnafBase::new(M_issuer.MAC.P);
                 let enc_migration_table = self.blockage_migration_table.encrypt_table(
                     L_issuer.id.unwrap(),
                     &self.bridge_table,

src/proto/trust_promotion.rs

@@ -38,9 +38,8 @@ use crate::migration_table;
 use crate::migration_table::ENC_MIGRATION_BYTES;
 use cmz::*;
 #[cfg(feature = "bridgeauth")]
-use curve25519_dalek::ristretto::RistrettoBasepointTable;
 use curve25519_dalek::ristretto::RistrettoPoint as G;
-use group::Group;
+use group::{Group, WnafBase};
 use rand_core::RngCore;
 use sha2::Sha512;
 use std::collections::HashMap;
@@ -152,8 +151,7 @@ impl BridgeAuth {
             },
         ) {
             Ok((response, (L_issuer, M_issuer))) => {
-                let Pktable: RistrettoBasepointTable =
-                    RistrettoBasepointTable::create(&M_issuer.MAC.P);
+                let Pktable: WnafBase<G, WNAF_SIZE> = WnafBase::new(M_issuer.MAC.P);
                 let enc_migration_table = self.trustup_migration_table.encrypt_table(
                     L_issuer.id.unwrap(),
                     &self.bridge_table,