From 086e1a6a70065c13b8dc4875ee8f45ba15b79a72 Mon Sep 17 00:00:00 2001
From: Vecna <vvecna@uwaterloo.ca>
Date: Tue, 28 Nov 2023 17:56:49 -0500
Subject: [PATCH] Add hash of bucket as type of proof of bridge knowledge

---
 src/lib.rs | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index 105162d..4977d72 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,6 @@
 use curve25519_dalek::scalar::Scalar;
 use ed25519_dalek::{Signature, Signer, SigningKey, Verifier, VerifyingKey};
-use lox_library::bridge_table::BridgeLine;
+use lox_library::bridge_table::{BridgeLine, MAX_BRIDGES_PER_BUCKET};
 use serde::{Deserialize, Serialize};
 use sha1::{Digest, Sha1};
 use sha3::Sha3_256;
@@ -33,11 +33,24 @@ pub fn get_bridge_signing_pubkey(fingerprint: &[u8; 20]) -> VerifyingKey {
     keypair.verifying_key()
 }
 
+/// Get bucket from hash of bucket ID, requires some oracle
+pub fn get_bucket(beta_hash: &[u8; 32]) -> [BridgeLine; MAX_BRIDGES_PER_BUCKET] {
+    // TODO
+    // for now just return bucket of empty bridgelines
+    [
+        BridgeLine::default(),
+        BridgeLine::default(),
+        BridgeLine::default(),
+    ]
+}
+
 /// Proof that the user knows (and should be able to access) a given bridge
 #[derive(Serialize, Deserialize)]
 pub enum ProofOfBridgeKnowledge {
     /// Hash of bridge line as proof of knowledge of bridge line
     HashOfBridgeLine { hash: [u8; 32] },
+    /// Hash of bucket ID for Lox user
+    HashOfBucket { hash: [u8; 32] },
 }
 
 impl ProofOfBridgeKnowledge {
@@ -50,6 +63,17 @@ impl ProofOfBridgeKnowledge {
                 let bl_hash: [u8; 32] = hasher.finalize().into();
                 hash == &bl_hash
             }
+            ProofOfBridgeKnowledge::HashOfBucket { ref hash } => {
+                let bucket = get_bucket(&hash);
+                for bl in bucket {
+                    let mut hasher = Sha1::new();
+                    hasher.update(bl.uid_fingerprint.to_le_bytes());
+                    if fingerprint == <[u8; 20]>::from(hasher.finalize()) {
+                        return true;
+                    }
+                }
+                false
+            }
         }
     }
 }