Update ciphersuite/dkg MSRVs

Presumably notably slower on platforms with std, yet only when compiled with old
versions of Rust for which the option is this or no support anyways.

Cargo.lock

@@ -2634,7 +2634,7 @@ dependencies = [
 
 [[package]]
 name = "ff-group-tests"
-version = "0.13.1"
+version = "0.13.2"
 dependencies = [
  "bls12_381",
  "ff",
@@ -9613,6 +9613,12 @@ version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
 
+[[package]]
+name = "spin"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d5fe4ccb98d9c292d56fec89a5e07da7fc4cf0dc11e156b41793132775d3e591"
+
 [[package]]
 name = "spki"
 version = "0.7.3"
@@ -9686,10 +9692,11 @@ dependencies = [
 
 [[package]]
 name = "std-shims"
-version = "0.1.2"
+version = "0.1.3"
 dependencies = [
  "hashbrown 0.14.5",
- "spin 0.9.8",
+ "rustversion",
+ "spin 0.10.0",
 ]
 
 [[package]]

Cargo.toml

@@ -160,6 +160,7 @@ directories-next = { path = "patches/directories-next" }
 [workspace.lints.clippy]
 unwrap_or_default = "allow"
 manual_is_multiple_of = "allow"
+incompatible_msrv = "allow" # Manually verified with a GitHub workflow
 borrow_as_ptr = "deny"
 cast_lossless = "deny"
 cast_possible_truncation = "deny"

common/std-shims/Cargo.toml

@@ -1,13 +1,13 @@
 [package]
 name = "std-shims"
-version = "0.1.2"
+version = "0.1.3"
 description = "A series of std shims to make alloc more feasible"
 license = "MIT"
 repository = "https://github.com/serai-dex/serai/tree/develop/common/std-shims"
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["nostd", "no_std", "alloc", "io"]
 edition = "2021"
-rust-version = "1.80"
+rust-version = "1.64"
 
 [package.metadata.docs.rs]
 all-features = true
@@ -17,7 +17,8 @@ rustdoc-args = ["--cfg", "docsrs"]
 workspace = true
 
 [dependencies]
-spin = { version = "0.9", default-features = false, features = ["use_ticket_mutex", "lazy"] }
+rustversion = { version = "1", default-features = false }
+spin = { version = "0.10", default-features = false, features = ["use_ticket_mutex", "once", "lazy"] }
 hashbrown = { version = "0.14", default-features = false, features = ["ahash", "inline-more"] }
 
 [features]

common/std-shims/README.md

@@ -3,4 +3,9 @@
 A crate which passes through to std when the default `std` feature is enabled,
 yet provides a series of shims when it isn't.
 
-`HashSet` and `HashMap` are provided via `hashbrown`.
+No guarantee of one-to-one parity is provided. The shims provided aim to be sufficient for the
+average case.
+
+`HashSet` and `HashMap` are provided via `hashbrown`. Synchronization primitives are provided via
+`spin` (avoiding a requirement on `critical-section`).
+types are not guaranteed to be

common/std-shims/src/lib.rs

@@ -11,3 +11,64 @@ pub mod io;
 pub use alloc::vec;
 pub use alloc::str;
 pub use alloc::string;
+
+pub mod prelude {
+  #[rustversion::before(1.73)]
+  #[doc(hidden)]
+  pub trait StdShimsDivCeil {
+    fn div_ceil(self, rhs: Self) -> Self;
+  }
+  #[rustversion::before(1.73)]
+  mod impl_divceil {
+    use super::StdShimsDivCeil;
+    impl StdShimsDivCeil for u8 {
+      fn div_ceil(self, rhs: Self) -> Self {
+        (self + (rhs - 1)) / rhs
+      }
+    }
+    impl StdShimsDivCeil for u16 {
+      fn div_ceil(self, rhs: Self) -> Self {
+        (self + (rhs - 1)) / rhs
+      }
+    }
+    impl StdShimsDivCeil for u32 {
+      fn div_ceil(self, rhs: Self) -> Self {
+        (self + (rhs - 1)) / rhs
+      }
+    }
+    impl StdShimsDivCeil for u64 {
+      fn div_ceil(self, rhs: Self) -> Self {
+        (self + (rhs - 1)) / rhs
+      }
+    }
+    impl StdShimsDivCeil for u128 {
+      fn div_ceil(self, rhs: Self) -> Self {
+        (self + (rhs - 1)) / rhs
+      }
+    }
+    impl StdShimsDivCeil for usize {
+      fn div_ceil(self, rhs: Self) -> Self {
+        (self + (rhs - 1)) / rhs
+      }
+    }
+  }
+
+  #[cfg(feature = "std")]
+  #[rustversion::before(1.74)]
+  #[doc(hidden)]
+  pub trait StdShimsIoErrorOther {
+    fn other<E>(error: E) -> Self
+    where
+      E: Into<Box<dyn std::error::Error + Send + Sync>>;
+  }
+  #[cfg(feature = "std")]
+  #[rustversion::before(1.74)]
+  impl StdShimsIoErrorOther for std::io::Error {
+    fn other<E>(error: E) -> Self
+    where
+      E: Into<Box<dyn std::error::Error + Send + Sync>>,
+    {
+      std::io::Error::new(std::io::ErrorKind::Other, error)
+    }
+  }
+}

common/std-shims/src/sync.rs

@@ -25,7 +25,20 @@ mod mutex_shim {
 }
 pub use mutex_shim::{ShimMutex as Mutex, MutexGuard};
 
+#[cfg(not(feature = "std"))]
+pub use spin::Once as OnceLock;
+#[rustversion::before(1.70)]
 #[cfg(feature = "std")]
-pub use std::sync::LazyLock;
+pub use spin::Once as OnceLock;
+#[rustversion::since(1.70)]
+#[cfg(feature = "std")]
+pub use std::sync::OnceLock;
+
 #[cfg(not(feature = "std"))]
 pub use spin::Lazy as LazyLock;
+#[rustversion::before(1.80)]
+#[cfg(feature = "std")]
+pub use spin::Lazy as LazyLock;
+#[rustversion::since(1.80)]
+#[cfg(feature = "std")]
+pub use std::sync::LazyLock;

crypto/ciphersuite/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/ciphersuite
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["ciphersuite", "ff", "group"]
 edition = "2021"
-rust-version = "1.80"
+rust-version = "1.73"
 
 [package.metadata.docs.rs]
 all-features = true

crypto/ciphersuite/src/dalek.rs

@@ -28,12 +28,6 @@ macro_rules! dalek_curve {
         $Point::generator()
       }
 
-      fn reduce_512(mut scalar: [u8; 64]) -> Self::F {
-        let res = Scalar::from_bytes_mod_order_wide(&scalar);
-        scalar.zeroize();
-        res
-      }
-
       fn hash_to_F(dst: &[u8], data: &[u8]) -> Self::F {
         Scalar::from_hash(Sha512::new_with_prefix(&[dst, data].concat()))
       }

crypto/ciphersuite/src/ed448.rs

@@ -66,12 +66,6 @@ impl Ciphersuite for Ed448 {
     Point::generator()
   }
 
-  fn reduce_512(mut scalar: [u8; 64]) -> Self::F {
-    let res = Self::hash_to_F(b"Ciphersuite-reduce_512", &scalar);
-    scalar.zeroize();
-    res
-  }
-
   fn hash_to_F(dst: &[u8], data: &[u8]) -> Self::F {
     Scalar::wide_reduce(Self::H::digest([dst, data].concat()).as_ref().try_into().unwrap())
   }

crypto/ciphersuite/src/kp256.rs

@@ -6,7 +6,7 @@ use group::ff::PrimeField;
 
 use elliptic_curve::{
   generic_array::GenericArray,
-  bigint::{NonZero, CheckedAdd, Encoding, U384, U512},
+  bigint::{NonZero, CheckedAdd, Encoding, U384},
   hash2curve::{Expander, ExpandMsg, ExpandMsgXmd},
 };
 
@@ -31,22 +31,6 @@ macro_rules! kp_curve {
         $lib::ProjectivePoint::GENERATOR
       }
 
-      fn reduce_512(scalar: [u8; 64]) -> Self::F {
-        let mut modulus = [0; 64];
-        modulus[32 ..].copy_from_slice(&(Self::F::ZERO - Self::F::ONE).to_bytes());
-        let modulus = U512::from_be_slice(&modulus).checked_add(&U512::ONE).unwrap();
-
-        let mut wide =
-          U512::from_be_bytes(scalar).rem(&NonZero::new(modulus).unwrap()).to_be_bytes();
-
-        let mut array = *GenericArray::from_slice(&wide[32 ..]);
-        let res = $lib::Scalar::from_repr(array).unwrap();
-
-        wide.zeroize();
-        array.zeroize();
-        res
-      }
-
       fn hash_to_F(dst: &[u8], msg: &[u8]) -> Self::F {
         // While one of these two libraries does support directly hashing to the Scalar field, the
         // other doesn't. While that's probably an oversight, this is a universally working method

crypto/ciphersuite/src/lib.rs

@@ -3,8 +3,11 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use core::fmt::Debug;
-#[cfg(any(feature = "alloc", feature = "std"))]
+#[allow(unused_imports)]
-use std_shims::io::{self, Read};
+use std_shims::{
+  prelude::*,
+  io::{self, Read},
+};
 
 use rand_core::{RngCore, CryptoRng};
 
@@ -62,12 +65,6 @@ pub trait Ciphersuite:
   // While group does provide this in its API, privacy coins may want to use a custom basepoint
   fn generator() -> Self::G;
 
-  /// Reduce 512 bits into a uniform scalar.
-  ///
-  /// If 512 bits is insufficient to perform a reduction into a uniform scalar, the ciphersuite
-  /// will perform a hash to sample the necessary bits.
-  fn reduce_512(scalar: [u8; 64]) -> Self::F;
-
   /// Hash the provided domain-separation tag and message to a scalar. Ciphersuites MAY naively
   /// prefix the tag to the message, enabling transpotion between the two. Accordingly, this
   /// function should NOT be used in any scheme where one tag is a valid substring of another

crypto/dalek-ff-group/src/field.rs

@@ -216,6 +216,20 @@ impl PrimeFieldBits for FieldElement {
 }
 
 impl FieldElement {
+  /// Create a FieldElement from a `crypto_bigint::U256`.
+  ///
+  /// This will reduce the `U256` by the modulus, into a member of the field.
+  pub const fn from_u256(u256: &U256) -> Self {
+    FieldElement(Residue::new(u256))
+  }
+
+  /// Create a `FieldElement` from the reduction of a 512-bit number.
+  ///
+  /// The bytes are interpreted in little-endian format.
+  pub fn wide_reduce(value: [u8; 64]) -> Self {
+    FieldElement(reduce(U512::from_le_bytes(value)))
+  }
+
   /// Interpret the value as a little-endian integer, square it, and reduce it into a FieldElement.
   pub fn from_square(value: [u8; 32]) -> FieldElement {
     let value = U256::from_le_bytes(value);

crypto/dalek-ff-group/src/lib.rs

@@ -359,7 +359,12 @@ macro_rules! dalek_group {
     $BASEPOINT_POINT: ident,
     $BASEPOINT_TABLE: ident
   ) => {
-    /// Wrapper around the dalek Point type. For Ed25519, this is restricted to the prime subgroup.
+    /// Wrapper around the dalek Point type.
+    ///
+    /// All operations will be restricted to a prime-order subgroup (equivalent to the group itself
+    /// in the case of Ristretto). The exposure of the internal element does allow bypassing this
+    /// however, which may lead to undefined/computationally-unsafe behavior, and is entirely at
+    /// the user's risk.
     #[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
     pub struct $Point(pub $DPoint);
     deref_borrow!($Point, $DPoint);

crypto/dkg/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/dkg"
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["dkg", "multisig", "threshold", "ff", "group"]
 edition = "2021"
-rust-version = "1.80"
+rust-version = "1.73"
 
 [package.metadata.docs.rs]
 all-features = true

crypto/dkg/dealer/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/dkg/dealer"
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["dkg", "multisig", "threshold", "ff", "group"]
 edition = "2021"
-rust-version = "1.80"
+rust-version = "1.73"
 
 [package.metadata.docs.rs]
 all-features = true

crypto/dkg/musig/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/dkg/musig"
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["dkg", "multisig", "threshold", "ff", "group"]
 edition = "2021"
-rust-version = "1.80"
+rust-version = "1.79"
 
 [package.metadata.docs.rs]
 all-features = true

crypto/dkg/promote/src/tests.rs

@@ -29,10 +29,6 @@ impl<C: Ciphersuite> Ciphersuite for AltGenerator<C> {
     C::G::generator() * <C as Ciphersuite>::hash_to_F(b"DKG Promotion Test", b"generator")
   }
 
-  fn reduce_512(scalar: [u8; 64]) -> Self::F {
-    <C as Ciphersuite>::reduce_512(scalar)
-  }
-
   fn hash_to_F(dst: &[u8], data: &[u8]) -> Self::F {
     <C as Ciphersuite>::hash_to_F(dst, data)
   }

crypto/dkg/recovery/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/dkg/recover
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["dkg", "multisig", "threshold", "ff", "group"]
 edition = "2021"
-rust-version = "1.80"
+rust-version = "1.73"
 
 [package.metadata.docs.rs]
 all-features = true

crypto/dkg/src/lib.rs

@@ -6,6 +6,8 @@ use core::{
   ops::Deref,
   fmt::{self, Debug},
 };
+#[allow(unused_imports)]
+use std_shims::prelude::*;
 use std_shims::{sync::Arc, vec, vec::Vec, collections::HashMap, io};
 
 use zeroize::{Zeroize, Zeroizing};

crypto/ff-group-tests/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ff-group-tests"
-version = "0.13.1"
+version = "0.13.2"
 description = "A collection of sanity tests for implementors of ff/group APIs"
 license = "MIT"
 repository = "https://github.com/serai-dex/serai/tree/develop/crypto/ff-group-tests"

crypto/multiexp/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/multiexp"
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["multiexp", "ff", "group"]
 edition = "2021"
-rust-version = "1.80"
+rust-version = "1.79"
 
 [package.metadata.docs.rs]
 all-features = true

crypto/schnorr/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/schnorr"
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["schnorr", "ff", "group"]
 edition = "2021"
-rust-version = "1.80"
+rust-version = "1.79"
 
 [package.metadata.docs.rs]
 all-features = true