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enabling zeroize for field elements #24

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enabling zeroize for field elements #24

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b138018
enable zeroized
zhenfeizhang Jan 3, 2020
28a2451
Update src/lib.rs
zhenfeizhang Jan 3, 2020
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1 change: 1 addition & 0 deletions Cargo.toml
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Expand Up @@ -14,6 +14,7 @@ edition = "2018"
byteorder = "1"
ff_derive = { version = "0.4.0", path = "ff_derive", optional = true }
rand_core = "0.5"
zeroize = {version = "1.1", features = ["zeroize_derive"]}

@str4d str4d Sep 4, 2020

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I'm still not sure that we want to have a required dependency on zeroize for the ff crate, especially as Zeroize is not part of any bound on the Field or PrimeField traits. I think I would prefer that we make this crate optional, and instead of using zeroize_derive we manually add an impl Zeroize for #repr if the zeroize feature is enabled.

This would require adding a zeroize feature flag to ff_derive, and then here:

[dependencies]
...
zeroize_crate = { package = "zeroize", version = "1.1", optional = true }

[features]
...
zeroize = ["ff_derive/zeroize", "zeroize_crate"]

(Crates that use namespaced-features can't be published, so we can't have a feature with the same name as a crate.)

cc @tarcieri.

@tarcieri tarcieri Sep 4, 2020 •
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We make zeroize optional in most of the RustCrypto crates, FWIW.

I think it may be possible to avoid adding a zeroize feature to ff_derive, but I'd have to double check what I have in mind: amely there's already a zeroize_derive crate, so it might be possible to use that rather than modifying ff_derive to have custom zeroize support?


[features]
default = []
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2 changes: 1 addition & 1 deletion ff_derive/src/lib.rs
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Expand Up @@ -116,7 +116,7 @@ fn fetch_attr(name: &str, attrs: &[syn::Attribute]) -> Option<String> {
// Implement PrimeFieldRepr for the wrapped ident `repr` with `limbs` limbs.
fn prime_field_repr_impl(repr: &syn::Ident, limbs: usize) -> proc_macro2::TokenStream {
quote! {
#[derive(Copy, Clone, PartialEq, Eq, Default)]
#[derive(Copy, Clone, PartialEq, Eq, Default, Zeroize)]
pub struct #repr(pub [u64; #limbs]);

impl ::std::fmt::Debug for #repr
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3 changes: 3 additions & 0 deletions src/lib.rs
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Expand Up @@ -11,6 +11,9 @@ extern crate ff_derive;
#[cfg(feature = "derive")]
pub use ff_derive::*;

#[macro_use]
extern crate zeroize;

@str4d str4d Sep 4, 2020

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This could then be removed.


use rand_core::RngCore;
use std::error::Error;
use std::fmt;
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