Merge pull request #24 from cryspen/jonas/wasm-demo

WASM demo

Author: jschneider-bensch

hacspec-scrambledb/oprf/Cargo.toml

@@ -11,10 +11,12 @@ p256.workspace = true
 hash-to-curve.workspace = true
 elgamal.workspace = true
 hacspec_lib.workspace = true
+sha256.workspace = true
 
 [dev-dependencies]
 serde_json = { version = "1.0.102" }
 hex = { version = "0.4.3", features = ["serde"] }
 serde = { version = "1.0.180", features = ["derive"] }
 log = "0.4.19"
 pretty_env_logger = "0.5.0"
+rand = "0.8.5"

hacspec-scrambledb/oprf/src/coprf/coprf_online.rs

@@ -20,10 +20,7 @@ use elgamal::Ciphertext;
 use hacspec_lib::Randomness;
 
 use super::coprf_setup::{BlindingPublicKey, CoPRFKey};
-use crate::{
-    coprf::coprf_setup::{CoPRFReceiverContext, CoPRFRequesterContext},
-    p256_sha256, Error,
-};
+use crate::{coprf::coprf_setup::CoPRFReceiverContext, p256_sha256, Error};
 use p256::{NatMod, P256Point};
 
 /// CoPRF Inputs can be arbitrary byte strings.
@@ -100,23 +97,25 @@ pub fn prepare_blind_convert(
 /// collusion-resistance.
 pub fn blind_convert(
     bpk: BlindingPublicKey,
-    key_i: CoPRFKey,
-    key_j: CoPRFKey,
+    key_from: CoPRFKey,
+    key_to: CoPRFKey,
     blind_input: BlindInput,
     randomness: &mut Randomness,
 ) -> Result<BlindOutput, Error> {
-    let delta = key_j * key_i.inv();
+    let delta = key_to * key_from.inv();
     let ctx_rerandomized = elgamal::rerandomize(bpk, blind_input, randomness)?;
     elgamal::scalar_mul_ciphertext(delta, ctx_rerandomized).map_err(|e| e.into())
 }
 
 #[cfg(test)]
 mod tests {
+    use crate::coprf::coprf_setup::{derive_key, CoPRFEvaluatorContext};
+
     use super::*;
 
     // =========== Unblinded Operations ===========
 
-    /// The clear evaluation of the PRF based on the PRF by Naor, Pinkas, and Reingold:
+    /// The cleartext evaluation of the PRF based on the PRF by Naor, Pinkas, and Reingold:
     ///
     /// ```text
     /// PRF: K x X -> G
@@ -154,13 +153,195 @@ mod tests {
     /// is performed by first computing a `delta` scalar from both evaluation
     /// keys, which when mulitplied with the output to convert will cancel out
     /// the original evaluation key and multiply by the target evaluation key.
-    pub fn convert(key_i: CoPRFKey, key_j: CoPRFKey, y: Output) -> Result<Output, Error> {
-        let delta = key_j * key_i.inv();
+    pub fn convert(
+        key_origin: CoPRFKey,
+        key_destination: CoPRFKey,
+        y: Output,
+    ) -> Result<Output, Error> {
+        let delta = key_destination * key_origin.inv();
         let result = p256::p256_point_mul(delta, y)?;
 
         Ok(result)
     }
 
+    fn generate_randomness() -> Randomness {
+        use rand::prelude::*;
+
+        let mut rng = rand::thread_rng();
+        let mut randomness = [0u8; 1000000];
+        rng.fill_bytes(&mut randomness);
+        let randomness = Randomness::new(randomness.to_vec());
+
+        randomness
+    }
+
+    #[test]
+    fn self_test_eval_convert() {
+        let mut randomness = generate_randomness();
+
+        let test_context = b"Test";
+        let test_input = b"TestInput";
+        let evaluator_context = CoPRFEvaluatorContext::new(&mut randomness).unwrap();
+
+        let key_origin1 = derive_key(&evaluator_context, b"1").unwrap();
+        let key_origin2 = derive_key(&evaluator_context, b"2").unwrap();
+        let key_destination = derive_key(&evaluator_context, b"3").unwrap();
+
+        let y_under_origin1 = evaluate(test_context, key_origin1, test_input).unwrap();
+        let y_under_origin2 = evaluate(test_context, key_origin2, test_input).unwrap();
+
+        let y_under_destination = evaluate(test_context, key_destination, test_input).unwrap();
+        let converted_y_from_1 = convert(key_origin1, key_destination, y_under_origin1).unwrap();
+        let converted_y_from_2 = convert(key_origin2, key_destination, y_under_origin2).unwrap();
+
+        assert_eq!(converted_y_from_1, converted_y_from_2);
+        assert_eq!(converted_y_from_1, y_under_destination);
+    }
+
+    #[test]
+    fn test_blind_evaluate() {
+        let mut randomness = generate_randomness();
+
+        let test_context = b"Test";
+        let test_input = b"TestInput";
+        let evaluator_context = CoPRFEvaluatorContext::new(&mut randomness).unwrap();
+        let receiver_context = CoPRFReceiverContext::new(&mut randomness);
+
+        let blind_input = blind(
+            receiver_context.get_bpk(),
+            test_input,
+            test_context.to_vec(),
+            &mut randomness,
+        )
+        .unwrap();
+
+        let evaluation_key = derive_key(&evaluator_context, b"TestKey").unwrap();
+        let blind_result = blind_evaluate(
+            evaluation_key,
+            receiver_context.get_bpk(),
+            blind_input,
+            &mut randomness,
+        )
+        .unwrap();
+
+        let unblinded_result = finalize(&receiver_context, blind_result).unwrap();
+
+        let expected_result = evaluate(test_context, evaluation_key, test_input).unwrap();
+
+        assert_eq!(unblinded_result, expected_result);
+    }
+
     #[test]
-    fn test_name() {}
+    fn blind_convergence() {
+        let mut randomness = generate_randomness();
+
+        let test_context = b"Test";
+        let test_input = b"TestInput";
+        let evaluator_context = CoPRFEvaluatorContext::new(&mut randomness).unwrap();
+        let receiver_context = CoPRFReceiverContext::new(&mut randomness);
+
+        let key_origin1 = derive_key(&evaluator_context, b"1").unwrap();
+        let key_origin2 = derive_key(&evaluator_context, b"2").unwrap();
+        let key_destination = derive_key(&evaluator_context, b"3").unwrap();
+
+        let y_under_destination = evaluate(test_context, key_destination, test_input).unwrap();
+        let y1 = evaluate(test_context, key_origin1, test_input).unwrap();
+        let y2 = evaluate(test_context, key_origin2, test_input).unwrap();
+
+        let blind1 =
+            prepare_blind_convert(receiver_context.get_bpk(), y1, &mut randomness).unwrap();
+        let blind2 =
+            prepare_blind_convert(receiver_context.get_bpk(), y2, &mut randomness).unwrap();
+
+        let blind_result_1 = blind_convert(
+            receiver_context.get_bpk(),
+            key_origin1,
+            key_destination,
+            blind1,
+            &mut randomness,
+        )
+        .unwrap();
+
+        let blind_result_2 = blind_convert(
+            receiver_context.get_bpk(),
+            key_origin2,
+            key_destination,
+            blind2,
+            &mut randomness,
+        )
+        .unwrap();
+
+        let res1 = finalize(&receiver_context, blind_result_1).unwrap();
+        let res2 = finalize(&receiver_context, blind_result_2).unwrap();
+
+        assert_eq!(res1, res2);
+        assert_eq!(res1, y_under_destination);
+    }
+    #[test]
+    fn test_blind_conversion() {
+        let mut randomness = generate_randomness();
+
+        let test_context = b"Test";
+        let test_input = b"TestInput";
+        let evaluator_context = CoPRFEvaluatorContext::new(&mut randomness).unwrap();
+        let receiver_context = CoPRFReceiverContext::new(&mut randomness);
+
+        let blind_input = blind(
+            receiver_context.get_bpk(),
+            test_input,
+            test_context.to_vec(),
+            &mut randomness,
+        )
+        .unwrap();
+
+        let key_eval = derive_key(&evaluator_context, b"TestKey").unwrap();
+        let key_destination = derive_key(&evaluator_context, b"DestinationKey").unwrap();
+
+        let blind_result = blind_evaluate(
+            key_eval,
+            receiver_context.get_bpk(),
+            blind_input,
+            &mut randomness,
+        )
+        .unwrap();
+
+        let expected_result = evaluate(test_context, key_destination, test_input).unwrap();
+
+        // converting the blinded result directly
+        let blind_converted_result = blind_convert(
+            receiver_context.get_bpk(),
+            key_eval,
+            key_destination,
+            blind_result,
+            &mut randomness,
+        )
+        .unwrap();
+
+        let unblinded_converted_result =
+            finalize(&receiver_context, blind_converted_result).unwrap();
+        assert_eq!(expected_result, unblinded_converted_result);
+
+        // converting after unblinding and re-blinding
+        let unblinded_intermediate_result = finalize(&receiver_context, blind_result).unwrap();
+
+        let prepped_input = prepare_blind_convert(
+            receiver_context.get_bpk(),
+            unblinded_intermediate_result,
+            &mut randomness,
+        )
+        .unwrap();
+
+        let blind_converted_result = blind_convert(
+            receiver_context.get_bpk(),
+            key_eval,
+            key_destination,
+            prepped_input,
+            &mut randomness,
+        )
+        .unwrap();
+
+        let unblinded_converted_result =
+            finalize(&receiver_context, blind_converted_result).unwrap();
+        assert_eq!(expected_result, unblinded_converted_result);
+    }
 }

hacspec-scrambledb/oprf/src/coprf/coprf_setup.rs

@@ -26,7 +26,8 @@ pub type BlindingPrivateKey = elgamal::DecryptionKey;
 /// `Nsk` bytes of entropy is provided to the key derivation
 /// algorithm, where `Nsk` is the number of bytes to represent a valid
 /// private key, i.e. a P256 scalar in our case.
-pub type CoPRFMasterSecret = [u8; 32];
+pub type CoPRFMasterSecret = Vec<u8>;
+const COPRF_MSK_BYTES: usize = 32;
 
 /// A coPRF evaluation key is identified by a bytestring of arbitrary
 /// length.
@@ -78,8 +79,9 @@ impl CoPRFEvaluatorContext {
     /// ### E.1.2. Evaluator Setup
     /// The coPRF evaluator holds the master secret as well as any PRF
     /// evaluation keys derived from it.
-    pub fn new(msk: CoPRFMasterSecret) -> Self {
-        CoPRFEvaluatorContext { msk }
+    pub fn new(randomness: &mut Randomness) -> Result<Self, Error> {
+        let msk = randomness.bytes(COPRF_MSK_BYTES)?.to_vec();
+        Ok(CoPRFEvaluatorContext { msk })
     }
 }
 
@@ -120,5 +122,7 @@ pub fn derive_key(context: &CoPRFEvaluatorContext, key_id: &[u8]) -> Result<CoPR
     let mut key_material = context.msk.to_vec();
     key_material.extend_from_slice(key_id);
 
-    p256::random_scalar(&mut Randomness::new(key_material)).map_err(|e| e.into())
+    let random_bytes = sha256::hash(&key_material);
+
+    p256::random_scalar(&mut Randomness::new(random_bytes.to_vec())).map_err(|e| e.into())
 }

hacspec-scrambledb/oprf/src/lib.rs

@@ -7,6 +7,7 @@ pub enum Error {
     CurveError,
     HashToCurveError,
     ElgamalError,
+    RandomnessError,
 }
 
 impl From<p256::Error> for Error {
@@ -27,6 +28,12 @@ impl From<elgamal::Error> for Error {
     }
 }
 
+impl From<hacspec_lib::Error> for Error {
+    fn from(_value: hacspec_lib::Error) -> Self {
+        Self::RandomnessError
+    }
+}
+
 // 3. Protocol
 pub mod protocol;
 

hacspec-scrambledb/prp/Cargo.toml

@@ -7,3 +7,6 @@ edition = "2021"
 
 [dependencies]
 hacspec_lib.workspace = true
+
+[dev-dependencies]
+rand = "0.8.5"

hacspec-scrambledb/prp/src/lib.rs

@@ -127,3 +127,19 @@ pub fn prp(input: Block, key: &ChaChaKey) -> Block {
     let state = chacha20_init(key, b"scrambledbiv", 1);
     chacha20_encrypt_block(state, 2, &input)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use rand::prelude::*;
+
+    #[test]
+    fn test_inversion() {
+        let mut key = [0u8; 32];
+        rand::thread_rng().fill_bytes(&mut key);
+
+        let block = [1u8; 64];
+        assert_ne!(block, prp(block, &key));
+        assert_eq!(block, prp(prp(block, &key), &key));
+    }
+}

hacspec-scrambledb/scrambledb/Cargo.toml

@@ -5,9 +5,42 @@ edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[lib]
+crate-type = ["rlib", "cdylib"]
+
 [dependencies]
 oprf.workspace = true
 elgamal.workspace = true
 prp.workspace = true
 p256.workspace = true
 hacspec_lib.workspace = true
+hash-to-curve.workspace = true
+
+wasm-bindgen = { version = "0.2.87", optional = true }
+rand = { version = "0.8.5", optional = true }
+getrandom = { version = "0.2.10", features = ["js"], optional = true }
+hex = { version = "0.4.3", optional = true }
+
+
+gloo-utils = { version = "0.1", features = ["serde"] }
+serde_json = "1.0.106"
+
+[dependencies.web-sys]
+version = "0.3.4"
+optional = true
+features = [
+    'Document',
+    'Element',
+    'HtmlElement',
+    'Node',
+    'Window',
+    'console',
+    'HtmlTableElement',
+    'HtmlTableRowElement',
+]
+
+[features]
+wasm = ["wasm-bindgen", "getrandom", "web-sys", "rand", "hex"]
+
+[dev-dependencies]
+scrambledb = { path = ".", features = ["rand"] }

hacspec-scrambledb/scrambledb/src/error.rs

@@ -12,6 +12,7 @@ impl From<oprf::Error> for Error {
             oprf::Error::CurveError => Self::CorruptedData,
             oprf::Error::HashToCurveError => Self::CorruptedData,
             oprf::Error::ElgamalError => Self::RandomnessError,
+            oprf::Error::RandomnessError => Self::RandomnessError,
         }
     }
 }