From 4231150c1cbf1a0b1abab4c33ef54570e0c0b799 Mon Sep 17 00:00:00 2001
From: Sarah Jamie Lewis <sarah@openprivacy.ca>
Date: Mon, 1 Feb 2021 11:28:40 -0800
Subject: [PATCH] A few small convieniance functions for the simulator /
 integrations

---
 src/lib.rs | 63 +++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 50 insertions(+), 13 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index e8cf965..e783732 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,13 +22,25 @@ use std::ops::{Add, Mul, Sub};
 /// * Correctness: Valid tags constructed for a specific public key will always validate when tested using the detection key
 /// * Fuzziness: Invalid tags will produce false positives with probability _p_ related to the security property (_γ_)
 /// * Security: An adversarial server with access to the detection key is unable to distinguish false positives from true positives. (Detection Ambiguity)
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct FuzzyTag {
     u: RistrettoPoint,
     y: Scalar,
     ciphertexts: BitVec,
 }
 
+impl Display for FuzzyTag {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "{} {} {}",
+            hex::encode(self.u.compress().as_bytes()),
+            hex::encode(self.y.as_bytes()),
+            hex::encode(self.ciphertexts.to_bytes())
+        )
+    }
+}
+
 /// The complete secret key. Can't directly be used for testing. Instead you will need to generate
 /// a FuzzyDetectionKey using extract
 #[derive(Debug, Serialize, Deserialize)]
@@ -50,9 +62,30 @@ impl FuzzySecretKey {
 
 /// A collection of "secret" data that can be used to determine if a `FuzzyTag` was intended for
 /// the derived public key with probability p
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct FuzzyDetectionKey(Vec<Scalar>);
 
+impl FuzzyDetectionKey {
+    /// a convenient id for a detection key for internal accounting purposes
+    /// do not expose this to applications
+    pub fn id(&self) -> String {
+        let mut hash = sha3::Sha3_256::new();
+        for s in self.0.iter() {
+            hash.update(s.as_bytes())
+        }
+        format!(
+            "{}",
+            hex::encode(hash.finalize().as_slice()),
+        )
+    }
+}
+
+impl Display for FuzzyDetectionKey {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.id())
+    }
+}
+
 impl FuzzyDetectionKey {
     /// calculate the ideal false positive rate of this detection key
     /// ```
@@ -133,6 +166,20 @@ impl FuzzyDetectionKey {
 pub struct FuzzyPublicKey(Vec<RistrettoPoint>);
 
 impl FuzzyPublicKey {
+
+    /// a convenient id for a public key for internal accounting purposes
+    /// do not expose this to applications
+    pub fn id(&self) -> String {
+        let mut hash = sha3::Sha3_256::new();
+        for s in self.0.iter() {
+            hash.update(s.compress().as_bytes())
+        }
+        format!(
+            "{}",
+            hex::encode(hash.finalize().as_slice()),
+        )
+    }
+
     /// generate a new tag for this public key
     /// Example:
     /// ```
@@ -182,17 +229,7 @@ impl FuzzyPublicKey {
     }
 }
 
-impl Display for FuzzyTag {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "{} {} {}",
-            hex::encode(self.u.compress().as_bytes()),
-            hex::encode(self.y.as_bytes()),
-            hex::encode(self.ciphertexts.to_bytes())
-        )
-    }
-}
+
 
 /// An identity keypair for generating and validating fuzzy meta tags.
 #[derive(Debug, Serialize, Deserialize)]