Qortal/pirate-librustzcash
1
0
Fork 1
mirror of https://github.com/Qortal/pirate-librustzcash.git synced 2025-11-02 20:37:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

Constant-time field inversion

Browse Source 
WARNING: THIS IS NOT ACTUALLY CONSTANT TIME YET!

The jubjub and bls12_381 crates will replace our constant-time usages,
but we NEED to fix ff_derive because other users will expect it to
implement the Field trait correctly.
This commit is contained in:
Jack Grigg
2019-05-14 14:18:37 +01:00
parent e85a9f309f
commit 40749da9a7
25 changed files with 243 additions and 221 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
ff/ff_derive/src/lib.rs
View File

@@ -791,6 +791,12 @@ fn prime_field_impl(
}
}
impl ::std::default::Default for #name {
fn default() -> #name {
#name::zero()
}
}
impl ::std::cmp::PartialEq for #name {
fn eq(&self, other: &#name) -> bool {
self.0 == other.0
@@ -1062,9 +1068,11 @@ fn prime_field_impl(
ret
}
fn inverse(&self) -> Option<Self> {
/// WARNING: THIS IS NOT ACTUALLY CONSTANT TIME YET!
/// TODO: Make this constant-time.
fn invert(&self) -> ::subtle::CtOption<Self> {
if self.is_zero() {
None
::subtle::CtOption::new(#name::zero(), ::subtle::Choice::from(0))
} else {
// Guajardo Kumar Paar Pelzl
// Efficient Software-Implementation of Finite Fields with Applications to Cryptography
@@ -1110,9 +1118,9 @@ fn prime_field_impl(
}
if u == one {
Some(b)
::subtle::CtOption::new(b, ::subtle::Choice::from(1))
} else {
Some(c)
::subtle::CtOption::new(c, ::subtle::Choice::from(1))
}
}
}