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#![cfg_attr(docsrs, feature(doc_auto_cfg))]
//! A modern Monero transaction library intended for usage in wallets. It prides
//! itself on accuracy, correctness, and removing common pit falls developers may
//! face.
//! monero-serai contains safety features, such as first-class acknowledgement of
//! the burning bug, yet also a high level API around creating transactions.
//! monero-serai also offers a FROST-based multisig, which is orders of magnitude
//! more performant than Monero's.
//! monero-serai was written for Serai, a decentralized exchange aiming to support
//! Monero. Despite this, monero-serai is intended to be a widely usable library,
//! accurate to Monero. monero-serai guarantees the functionality needed for Serai,
//! yet will not deprive functionality from other users, and may potentially leave
//! Serai's umbrella at some point.
//! Various legacy transaction formats are not currently implemented, yet
//! monero-serai is still increasing its support for various transaction types.
use lazy_static::lazy_static;
use rand_core::{RngCore, CryptoRng};
use zeroize::{Zeroize, ZeroizeOnDrop};
use sha3::{Digest, Keccak256};
use curve25519_dalek::{
constants::ED25519_BASEPOINT_TABLE,
scalar::Scalar,
edwards::{EdwardsPoint, EdwardsBasepointTable},
};
pub use monero_generators::H;
#[cfg(feature = "multisig")]
pub(crate) mod frost;
mod serialize;
/// RingCT structs and functionality.
pub mod ringct;
/// Transaction structs.
pub mod transaction;
/// Block structs.
pub mod block;
/// Monero daemon RPC interface.
pub mod rpc;
/// Wallet functionality, enabling scanning and sending transactions.
pub mod wallet;
#[cfg(test)]
mod tests;
/// Monero protocol version. v15 is omitted as v15 was simply v14 and v16 being active at the same
/// time, with regards to the transactions supported. Accordingly, v16 should be used during v15.
#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
#[allow(non_camel_case_types)]
pub enum Protocol {
Unsupported,
v14,
v16,
}
impl Protocol {
/// Amount of ring members under this protocol version.
pub fn ring_len(&self) -> usize {
match self {
Protocol::Unsupported => panic!("Unsupported protocol version"),
Protocol::v14 => 11,
Protocol::v16 => 16,
}
}
/// Whether or not the specified version uses Bulletproofs or Bulletproofs+.
/// This method will likely be reworked when versions not using Bulletproofs at all are added.
pub fn bp_plus(&self) -> bool {
match self {
Protocol::Unsupported => panic!("Unsupported protocol version"),
Protocol::v14 => false,
Protocol::v16 => true,
}
}
}
lazy_static! {
static ref H_TABLE: EdwardsBasepointTable = EdwardsBasepointTable::create(&H);
}
/// Transparent structure representing a Pedersen commitment's contents.
#[allow(non_snake_case)]
#[derive(Clone, PartialEq, Eq, Debug, Zeroize, ZeroizeOnDrop)]
pub struct Commitment {
pub mask: Scalar,
pub amount: u64,
}
impl Commitment {
/// The zero commitment, defined as a mask of 1 (as to not be the identity) and a 0 amount.
pub fn zero() -> Commitment {
Commitment { mask: Scalar::one(), amount: 0 }
}
pub fn new(mask: Scalar, amount: u64) -> Commitment {
Commitment { mask, amount }
}
/// Calculate a Pedersen commitment, as a point, from the transparent structure.
pub fn calculate(&self) -> EdwardsPoint {
(&self.mask * &ED25519_BASEPOINT_TABLE) + (&Scalar::from(self.amount) * &*H_TABLE)
}
}
/// Support generating a random scalar using a modern rand, as dalek's is notoriously dated.
pub fn random_scalar<R: RngCore + CryptoRng>(rng: &mut R) -> Scalar {
let mut r = [0; 64];
rng.fill_bytes(&mut r);
Scalar::from_bytes_mod_order_wide(&r)
}
pub(crate) fn hash(data: &[u8]) -> [u8; 32] {
Keccak256::digest(data).into()
}
/// Hash the provided data to a scalar via keccak256(data) % l.
pub fn hash_to_scalar(data: &[u8]) -> Scalar {
let scalar = Scalar::from_bytes_mod_order(hash(data));
// Monero will explicitly error in this case
// This library acknowledges its practical impossibility of it occurring, and doesn't bother to
// code in logic to handle it. That said, if it ever occurs, something must happen in order to
// not generate/verify a proof we believe to be valid when it isn't
assert!(scalar != Scalar::zero(), "ZERO HASH: {:?}", data);
scalar
}