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Add tests for impl (Add|Sub)(Assign) for ValueCommitment

This commit is contained in:
Deirdre Connolly 2020-10-01 23:12:05 -04:00 committed by Deirdre Connolly
parent d4da79af86
commit 7cd730c552
1 changed files with 111 additions and 2 deletions
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113
zebra-chain/src/sapling/commitment.rs
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@ -241,13 +241,22 @@ impl ValueCommitment {
///
/// https://zips.z.cash/protocol/protocol.pdf#concretehomomorphiccommit
#[allow(non_snake_case)]
pub fn new<T>(csprng: &mut T, value: Amount<NonNegative>) -> Self
pub fn randomized<T>(csprng: &mut T, value: Amount) -> Self
where
T: RngCore + CryptoRng,
{
let v = jubjub::Fr::from(value);
let rcv = generate_trapdoor(csprng);
Self::new(rcv, value)
}
/// Generate a new _ValueCommitment_ from an existing _rcv_ on a _value_.
///
/// https://zips.z.cash/protocol/protocol.pdf#concretehomomorphiccommit
#[allow(non_snake_case)]
pub fn new(rcv: jubjub::Fr, value: Amount) -> Self {
let v = jubjub::Fr::from(value);
// TODO: These generator points can be generated once somewhere else to
// avoid having to recompute them on every new commitment.
let V = find_group_hash(*b"Zcash_cv", b"v");
@ -260,6 +269,8 @@ impl ValueCommitment {
#[cfg(test)]
mod tests {
use std::ops::Neg;
use super::*;
#[test]
@ -275,4 +286,102 @@ mod tests {
assert_eq!(result, test_vector.output_point);
}
}
#[test]
fn test_add() {
let identity = ValueCommitment(jubjub::AffinePoint::identity());
let g = ValueCommitment(jubjub::AffinePoint::from_raw_unchecked(
jubjub::Fq::from_raw([
0xe4b3_d35d_f1a7_adfe,
0xcaf5_5d1b_29bf_81af,
0x8b0f_03dd_d60a_8187,
0x62ed_cbb8_bf37_87c8,
]),
jubjub::Fq::from_raw([
0x0000_0000_0000_000b,
0x0000_0000_0000_0000,
0x0000_0000_0000_0000,
0x0000_0000_0000_0000,
]),
));
assert_eq!(identity + g, g);
}
#[test]
fn test_add_assign() {
let mut identity = ValueCommitment(jubjub::AffinePoint::identity());
let g = ValueCommitment(jubjub::AffinePoint::from_raw_unchecked(
jubjub::Fq::from_raw([
0xe4b3_d35d_f1a7_adfe,
0xcaf5_5d1b_29bf_81af,
0x8b0f_03dd_d60a_8187,
0x62ed_cbb8_bf37_87c8,
]),
jubjub::Fq::from_raw([
0x0000_0000_0000_000b,
0x0000_0000_0000_0000,
0x0000_0000_0000_0000,
0x0000_0000_0000_0000,
]),
));
identity += g;
let new_g = identity;
assert_eq!(new_g, g);
}
#[test]
fn test_sub() {
let g_point = jubjub::AffinePoint::from_raw_unchecked(
jubjub::Fq::from_raw([
0xe4b3_d35d_f1a7_adfe,
0xcaf5_5d1b_29bf_81af,
0x8b0f_03dd_d60a_8187,
0x62ed_cbb8_bf37_87c8,
]),
jubjub::Fq::from_raw([
0x0000_0000_0000_000b,
0x0000_0000_0000_0000,
0x0000_0000_0000_0000,
0x0000_0000_0000_0000,
]),
);
let identity = ValueCommitment(jubjub::AffinePoint::identity());
let g = ValueCommitment(g_point);
assert_eq!(identity - g, ValueCommitment(g_point.neg()));
}
#[test]
fn test_sub_assign() {
let g_point = jubjub::AffinePoint::from_raw_unchecked(
jubjub::Fq::from_raw([
0xe4b3_d35d_f1a7_adfe,
0xcaf5_5d1b_29bf_81af,
0x8b0f_03dd_d60a_8187,
0x62ed_cbb8_bf37_87c8,
]),
jubjub::Fq::from_raw([
0x0000_0000_0000_000b,
0x0000_0000_0000_0000,
0x0000_0000_0000_0000,
0x0000_0000_0000_0000,
]),
);
let mut identity = ValueCommitment(jubjub::AffinePoint::identity());
let g = ValueCommitment(g_point);
identity -= g;
let new_g = identity;
assert_eq!(new_g, ValueCommitment(g_point.neg()));
}
}