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#[encrypted_library]
mod arcis_library {
/// Owner for shared data between the owner of a public key and the MXE.
///
/// Decrypting data owned by this owner requires participation from either:
/// * the whole MXE
/// * the public key owner.
#[derive(Debug, PartialEq)]
pub struct Shared {
pub public_key: ArcisX25519Pubkey,
pub(crate) nonce: u128,
}
impl Shared {
/// Creates an owner for shared data between the MXE and the public key owner.
pub fn new(public_key: ArcisX25519Pubkey) -> Self {
let nonce = ArcisRNG::gen_public_integer_from_width(128);
Self { public_key, nonce }
}
}
/// Owner of secret data.
/// Decrypting data owned by this owner requires participation from all nodes that comprise
/// the MXE cluster.
#[derive(Debug, PartialEq)]
pub struct Mxe {
pub(crate) nonce: u128,
}
impl Mxe {
/// Generate a nonce for the MXE. Used to encrypt data which can only be decrypted by the
/// nodes that comprise the cluster attached to the given MXE.
pub fn get() -> Self {
let nonce = ArcisRNG::gen_public_integer_from_width(128);
Self { nonce }
}
}
pub(crate) fn base58_to_32_uint8array(s: &[u8]) -> [u8; 32] {
fn base58_to_u8(c: u8) -> u8 {
#![allow(clippy::manual_range_contains)]
if b'1' <= c && c <= b'9' {
c - b'1'
} else if b'A' <= c && c <= b'H' {
c - b'A' + 9
} else if b'J' <= c && c <= b'N' {
c - b'J' + 17
} else if b'P' <= c && c <= b'Z' {
c - b'P' + 22
} else if b'a' <= c && c <= b'k' {
c - b'a' + 33
} else if b'm' <= c && c <= b'z' {
c - b'm' + 44
} else {
// Maybe some kind of assert or panic would be good.
127
}
}
fn op(a: &mut [u8; 32], factor: u8, carry: u8) {
let mut carry = carry as u16;
for a in a.iter_mut() {
let num = *a as u16 * factor as u16 + carry;
carry = num / 256;
*a = (num % 256) as u8;
}
}
let mut address = [0u8; 32];
for &c in s {
let b = base58_to_u8(c);
op(&mut address, 58, b);
}
address.reverse();
address
}
impl ArcisX25519Pubkey {
/// Creates an Arcis public key based on the base58-encoding of the Montgomery x-coordinate.
pub fn from_base58(s: &[u8]) -> Self {
let arr = base58_to_32_uint8array(s);
Self::from_uint8(&arr)
}
/// Creates an Arcis public key based on the uint8array-encoding of the Montgomery
/// x-coordinate.
pub fn from_uint8(s: &[u8]) -> Self {
if s.len() > 32 {
arcis_static_panic!("Length of arg in `from_uint8` is too big.");
}
let two_power_eight = BaseField25519::from_u64(256);
let mut x = BaseField25519::from_u8(0);
let mut factor = BaseField25519::from_u8(1);
for &b in s {
x += BaseField25519::from_u8(b) * factor;
factor *= two_power_eight;
}
Self::new_from_x(x)
}
}
impl<T: ArcisType> EncData<T> {
/// This does the same thing as `.to_arcis()` on the matching `Enc`.
///
/// This function exists for performance reasons: imagine you have an `#[instruction]`
/// with inputs `t: Enc<Shared, T>` and `u: Enc<Shared, U>` that have the same pubkey.
/// Arcis cannot know the pubkeys are equal and will have duplicate gates for each pubkey.
/// You have two ways of fixing the performance hit:
/// * Refactoring your `#[instruction]` inputs into `tu: Enc<Shared, (T, U)>`. But that may
/// require to change the smart contract and the whole way your app flows.
/// * Refactoring your `#[instruction]` inputs into `key: ArcisX25519Pubkey, t_nonce: u128,
/// t: EncData<T>, u_nonce: u128, u: EncData<U>`. This change will only require to change
/// the caller and the callee.
/// The first solution is slightly better in terms of performance if you can do it.
pub fn to_arcis_with_pubkey_and_nonce(
self,
public_key: ArcisX25519Pubkey,
nonce: u128,
) -> T {
let owner = Shared { public_key, nonce };
Enc { owner, data: self }.to_arcis()
}
}
}