serde serialization

Cargo.toml

@@ -11,10 +11,12 @@ hex = "0.4.2"
 rand = "0.7.3"
 curve25519-dalek = {version="3.0.0",  features=["serde"]}
 sha3 = "0.9.1"
-bit-vec = "0.6.3"
+bit-vec = {version="0.6.3", features=["serde"]}
+serde = {version="1.0.123", features=["derive"]}
 
 [dev-dependencies]
 criterion = {version="0.3", features=["html_reports"]}
+serde_json = "1.0.61"
 
 [[bench]]
 name = "fuzzy_tags_benches"

src/lib.rs

@@ -7,6 +7,8 @@ use curve25519_dalek::digest::Digest;
 use curve25519_dalek::ristretto::RistrettoPoint;
 use curve25519_dalek::scalar::Scalar;
 use rand::rngs::OsRng;
+use serde::Deserialize;
+use serde::Serialize;
 use sha3::Sha3_512;
 use std::fmt;
 use std::fmt::{Display, Formatter};
@@ -19,15 +21,28 @@ 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)]
+#[derive(Debug, Serialize, Deserialize)]
 pub struct FuzzyMetaTag {
     u: RistrettoPoint,
     y: Scalar,
     ciphertexts: BitVec,
 }
 
+/// The complete secret key. Can't directly be used for testing. Instead you will need to generate
+/// a FuzzyMetaDetectionKey using extract
+pub struct FuzzyMetaSecretKey(Vec<Scalar>);
+
+impl FuzzyMetaSecretKey {
+    /// extract a detection key for a given false positive (p = 2^-n)
+    pub fn extract(&self, n: usize) -> FuzzyMetaDetectionKey {
+        let parts = self.0.iter().take(n).cloned().collect();
+        FuzzyMetaDetectionKey { 0: parts }
+    }
+}
+
 /// A collection of "secret" data that can be used to determine if a `FuzzyMetaTag` was intended for
 /// the derived public key with probability p
+#[derive(Debug, Serialize, Deserialize)]
 pub struct FuzzyMetaDetectionKey(Vec<Scalar>);
 
 impl FuzzyMetaDetectionKey {
@@ -133,7 +148,7 @@ impl Display for FuzzyMetaTag {
 pub struct FuzzyMetaTagKeyPair {
     /// the detection key - this can be given to adversarial servers to help probabilistically
     /// filter messages (with a false-positive rate derived from γ and a 0% false negative rate)
-    pub detection_key: FuzzyMetaDetectionKey,
+    pub secret_key: FuzzyMetaSecretKey,
     /// the public key - this can be given to people who you want to contact you
     pub public_key: FuzzyMetaPublicKey,
 }
@@ -154,15 +169,15 @@ impl FuzzyMetaTagKeyPair {
             p_keys.push(pk_i);
         }
         FuzzyMetaTagKeyPair {
-            detection_key: FuzzyMetaDetectionKey { 0: s_keys },
+            secret_key: FuzzyMetaSecretKey { 0: s_keys },
             public_key: FuzzyMetaPublicKey { 0: p_keys },
         }
     }
 
     /// extract a detection key for a given false positive (p = 2^-n)
+    /// a facade for an extraction of the encapsulated secret key
     pub fn extract(&self, n: usize) -> FuzzyMetaDetectionKey {
-        let parts = self.detection_key.0.iter().take(n).cloned().collect();
+        self.secret_key.extract(n)
-        FuzzyMetaDetectionKey { 0: parts }
     }
 
     /// a hash function that takes 3 risretto points as a parameter and outputs 0 or 1.
@@ -190,6 +205,15 @@ impl FuzzyMetaTagKeyPair {
 mod tests {
     use crate::FuzzyMetaTagKeyPair;
 
+    #[test]
+    fn test_serialization() {
+        let key = FuzzyMetaTagKeyPair::generate(16);
+        let tag = key.public_key.generate_tag();
+        let detection_key = key.extract(10);
+        println!("{}", serde_json::to_string(&tag).unwrap());
+        println!("{}", serde_json::to_string(&detection_key).unwrap());
+    }
+
     #[test]
     fn correctness() {
         let number_of_messages = 100;
@@ -211,7 +235,7 @@ mod tests {
             let key2 = FuzzyMetaTagKeyPair::generate(gamma);
             let tag = key2.public_key.generate_tag();
             assert!(key2.extract(3).test_tag(&tag));
-            if key.extract(3).test_tag(&tag) == true {
+            if key.secret_key.extract(3).test_tag(&tag) == true {
                 false_positives += 1;
             }
         }