Merge pull request #39 from dusk-network/to_from_bytes

Add to/from bytes impls for Fee & Crossover

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.5.0] - 27-11-20
+### Added
+- To/From bytes impl for `Fee` & `Crossover`.
+
 ## [0.5.0-alpha] - 27-11-20
 ### Changed
 - No-Std compatibility.

Cargo.toml

@@ -1,14 +1,14 @@
 [package]
 name = "phoenix-core"
-version = "0.5.0-alpha"
+version = "0.5.0"
 authors = ["zer0 <matteo@dusk.network>", "Victor Lopez <victor@dusk.network"]
 edition = "2018"
 
 [dependencies]
 rand_core = "0.5.1"
 dusk-bls12_381 = {version = "0.3", default-features = false}
 dusk-jubjub = {version = "0.5", default-features = false}
-poseidon252 = {git = "https://github.com/dusk-network/Poseidon252", tag = "v0.14.1", default-features = false}
+poseidon252 = {git = "https://github.com/dusk-network/Poseidon252", tag = "v0.15.0", default-features = false}
 dusk-pki = {git = "https://github.com/dusk-network/dusk-pki", tag = "v0.4.1", default-features = false}
 canonical = {version = "0.4", optional = true}
 canonical_derive = {version = "0.4", optional = true}

src/crossover.rs

@@ -6,13 +6,15 @@
 
 //! Fee module contains the logic related to `Crossover` structure
 
-use crate::{BlsScalar, JubJubExtended, JubJubScalar};
+use crate::{BlsScalar, Error, JubJubExtended, JubJubScalar};
 
 #[cfg(feature = "canon")]
 use canonical::Canon;
 #[cfg(feature = "canon")]
 use canonical_derive::Canon;
 
+use dusk_jubjub::JubJubAffine;
+use dusk_pki::jubjub_decode;
 use poseidon252::cipher::PoseidonCipher;
 use poseidon252::sponge::hash;
 
@@ -34,6 +36,11 @@ impl PartialEq for Crossover {
 impl Eq for Crossover {}
 
 impl Crossover {
+    /// Returns the serialized size of the Crossover
+    pub const fn serialized_size() -> usize {
+        32 * 2 + PoseidonCipher::cipher_size_bytes()
+    }
+
     /// Returns a hash represented by `H(value_commitment)`
     pub fn hash(&self) -> BlsScalar {
         let value_commitment = self.value_commitment().to_hash_inputs();
@@ -55,4 +62,60 @@ impl Crossover {
     pub fn encrypted_data(&self) -> &PoseidonCipher {
         &self.encrypted_data
     }
+
+    /// Converts a Crossover into it's byte representation
+    pub fn to_bytes(&self) -> [u8; Crossover::serialized_size()] {
+        let mut buf = [0u8; Crossover::serialized_size()];
+        let mut n = 0;
+
+        buf[n..n + 32].copy_from_slice(
+            &JubJubAffine::from(&self.value_commitment).to_bytes()[..],
+        );
+        n += 32;
+
+        buf[n..n + 32].copy_from_slice(&self.nonce.to_bytes()[..]);
+        n += 32;
+
+        buf[n..n + PoseidonCipher::cipher_size_bytes()]
+            .copy_from_slice(&self.encrypted_data.to_bytes()[..]);
+        n += PoseidonCipher::cipher_size_bytes();
+
+        debug_assert_eq!(n, Crossover::serialized_size());
+
+        buf
+    }
+
+    /// Attempts to convert a byte representation of a note into a `Note`,
+    /// failing if the input is invalid
+    pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
+        if bytes.len() < Crossover::serialized_size() {
+            return Err(Error::InvalidCrossoverConversion);
+        }
+
+        let mut bytes_32 = [0u8; 32];
+        let mut one_cipher = [0u8; PoseidonCipher::cipher_size_bytes()];
+
+        let mut n = 0;
+
+        bytes_32.copy_from_slice(&bytes[n..n + 32]);
+        let value_commitment =
+            JubJubExtended::from(jubjub_decode::<JubJubAffine>(&bytes_32)?);
+        n += 32;
+
+        bytes_32.copy_from_slice(&bytes[n..n + 32]);
+        let nonce = jubjub_decode::<JubJubScalar>(&bytes_32)?;
+        n += 32;
+
+        one_cipher.copy_from_slice(
+            &bytes[n..n + PoseidonCipher::cipher_size_bytes()],
+        );
+        let encrypted_data = PoseidonCipher::from_bytes(&one_cipher)
+            .ok_or(Error::InvalidCipher)?;
+
+        Ok(Crossover {
+            value_commitment,
+            nonce,
+            encrypted_data,
+        })
+    }
 }

src/error.rs

@@ -23,6 +23,10 @@ pub enum Error {
     MissingViewKey,
     /// Invalid Note Type for conversion
     InvalidNoteConversion,
+    /// Invalid Crossover for conversion
+    InvalidCrossoverConversion,
+    /// Invalid Fee for conversion
+    InvalidFeeConversion,
     /// Dusk-Pki Error
     PKIError(PkiError),
     /// Poseidon Error

src/fee.rs

@@ -17,7 +17,7 @@ use canonical_derive::Canon;
 
 use core::cmp;
 
-use crate::{BlsScalar, JubJubScalar};
+use crate::{BlsScalar, Error, JubJubScalar};
 
 mod remainder;
 pub use remainder::Remainder;
@@ -42,6 +42,11 @@ impl PartialEq for Fee {
 impl Eq for Fee {}
 
 impl Fee {
+    /// Returns the serialized size of the Fee.
+    pub const fn serialized_size() -> usize {
+        8 * 2 + 64
+    }
+
     /// Create a new Fee with inner randomness
     pub fn new<R: RngCore + CryptoRng>(
         rng: &mut R,
@@ -97,6 +102,58 @@ impl Fee {
             stealth_address: self.stealth_address,
         }
     }
+
+    /// Converts a Fee into it's byte representation
+    pub fn to_bytes(&self) -> [u8; Fee::serialized_size()] {
+        let mut buf = [0u8; Fee::serialized_size()];
+        let mut n = 0;
+
+        buf[n..n + 8].copy_from_slice(&self.gas_limit.to_le_bytes()[..]);
+        n += 8;
+
+        buf[n..n + 8].copy_from_slice(&self.gas_price.to_le_bytes()[..]);
+        n += 8;
+
+        buf[n..n + 64].copy_from_slice(&self.stealth_address.to_bytes()[..]);
+        n += 64;
+
+        debug_assert_eq!(n, Fee::serialized_size());
+
+        buf
+    }
+
+    /// Attempts to convert a byte representation of a note into a `Note`,
+    /// failing if the input is invalid
+    pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
+        if bytes.len() < Fee::serialized_size() {
+            return Err(Error::InvalidFeeConversion);
+        }
+
+        let mut one_u64 = [0u8; 8];
+        let mut one_stealth_addr = [0u8; 64];
+
+        let mut n = 0;
+
+        one_u64.copy_from_slice(&bytes[n..n + 8]);
+        let gas_limit = u64::from_le_bytes(one_u64);
+        n += 8;
+
+        one_u64.copy_from_slice(&bytes[n..n + 8]);
+        let gas_price = u64::from_le_bytes(one_u64);
+        n += 8;
+
+        one_stealth_addr.copy_from_slice(&bytes[n..n + 64]);
+        let stealth_address = StealthAddress::from_bytes(&one_stealth_addr)?;
+        n += 64;
+
+        debug_assert_eq!(n, Fee::serialized_size());
+
+        Ok(Fee {
+            gas_limit,
+            gas_price,
+            stealth_address,
+        })
+    }
 }
 
 impl Ownable for Fee {

src/note.rs

@@ -308,7 +308,7 @@ impl Note {
             .copy_from_slice(&self.encrypted_data.to_bytes()[..]);
         n += PoseidonCipher::cipher_size_bytes();
 
-        assert_eq!(n, Note::serialized_size());
+        debug_assert_eq!(n, Note::serialized_size());
 
         buf
     }