WASM: add bindings for EphemeralKeyPair

ironfish-rust-wasm/src/keys/ephemeral.rs

@@ -0,0 +1,47 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::{
+    errors::IronfishError,
+    primitives::{Fr, SubgroupPoint},
+    wasm_bindgen_wrapper,
+};
+use wasm_bindgen::prelude::*;
+
+wasm_bindgen_wrapper! {
+    #[derive(Clone, PartialEq, Eq, Debug)]
+    pub struct EphemeralKeyPair(ironfish::keys::EphemeralKeyPair);
+}
+
+#[wasm_bindgen]
+impl EphemeralKeyPair {
+    #[wasm_bindgen(constructor)]
+    pub fn deserialize(bytes: &[u8]) -> Result<Self, IronfishError> {
+        Ok(Self(ironfish::keys::EphemeralKeyPair::read(bytes)?))
+    }
+
+    #[wasm_bindgen]
+    pub fn serialize(&self) -> Vec<u8> {
+        let mut buf = Vec::new();
+        self.0
+            .write(&mut buf)
+            .expect("failed to serialize ephemeral key pair");
+        buf
+    }
+
+    #[wasm_bindgen]
+    pub fn random() -> Self {
+        Self(ironfish::keys::EphemeralKeyPair::new())
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn secret(&self) -> Fr {
+        self.0.secret().to_owned().into()
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn public(&self) -> SubgroupPoint {
+        self.0.public().to_owned().into()
+    }
+}

ironfish-rust-wasm/src/keys/mod.rs

@@ -2,12 +2,14 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+mod ephemeral;
 mod mnemonics;
 mod proof_generation_key;
 mod public_address;
 mod sapling_key;
 mod view_keys;
 
+pub use ephemeral::EphemeralKeyPair;
 pub use mnemonics::Language;
 pub use proof_generation_key::ProofGenerationKey;
 pub use public_address::PublicAddress;

ironfish-rust/src/keys/ephemeral.rs

@@ -1,28 +1,41 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::errors::{IronfishError, IronfishErrorKind};
 use ff::Field;
 use ironfish_zkp::constants::PUBLIC_KEY_GENERATOR;
 use rand::thread_rng;
+use std::io;
 
 /// Diffie Hellman key exchange pair as used in note encryption.
 ///
 /// This can be used according to the protocol described in
 /// [`crate::keys::shared_secret`]
-#[derive(Default)]
+#[derive(Default, Clone, PartialEq, Eq, Debug)]
 pub struct EphemeralKeyPair {
     secret: ironfish_jubjub::Fr,
     public: ironfish_jubjub::SubgroupPoint,
 }
 
 impl EphemeralKeyPair {
     pub fn new() -> Self {
-        let secret = ironfish_jubjub::Fr::random(thread_rng());
+        loop {
+            let secret = ironfish_jubjub::Fr::random(thread_rng());
+            if let Ok(key_pair) = Self::from_secret(secret) {
+                break key_pair;
+            }
+        }
+    }
 
-        Self {
+    pub fn from_secret(secret: ironfish_jubjub::Fr) -> Result<Self, IronfishError> {
+        if secret == ironfish_jubjub::Fr::zero() || secret == ironfish_jubjub::Fr::one() {
+            return Err(IronfishError::new(IronfishErrorKind::InvalidSecret));
+        }
+        Ok(Self {
             secret,
             public: *PUBLIC_KEY_GENERATOR * secret,
-        }
+        })
     }
 
     pub fn secret(&self) -> &ironfish_jubjub::Fr {
@@ -32,6 +45,20 @@ impl EphemeralKeyPair {
     pub fn public(&self) -> &ironfish_jubjub::SubgroupPoint {
         &self.public
     }
+
+    pub fn read<R: io::Read>(mut reader: R) -> Result<Self, IronfishError> {
+        let mut secret_bytes = [0u8; 32];
+        reader.read_exact(&mut secret_bytes)?;
+        let secret = Option::from(ironfish_jubjub::Fr::from_bytes(&secret_bytes))
+            .ok_or_else(|| IronfishError::new(IronfishErrorKind::InvalidData))?;
+        Self::from_secret(secret)
+    }
+
+    pub fn write<W: io::Write>(&self, mut writer: W) -> Result<(), IronfishError> {
+        let secret_bytes = self.secret.to_bytes();
+        writer.write_all(&secret_bytes)?;
+        Ok(())
+    }
 }
 
 #[cfg(test)]