crypto: get rid of ThreadRng

Fixes #43 Signed-off-by: Eric Lagergren <[email protected]>
aranya-project · Jan 7, 2025 · 99fea54 · 99fea54
1 parent 6522a44
commit 99fea54
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Showing 3 changed files with 10 additions and 17 deletions.
diff --git a/crates/aranya-crypto-core/Cargo.toml b/crates/aranya-crypto-core/Cargo.toml
@@ -16,7 +16,6 @@ workspace = true
 [features]
 default = [
 	"getrandom",
-	#"trng",
 ]
 
 # Enable allocations.
@@ -93,9 +92,6 @@ std = [
 	# `#[cfg(...)]` blocks easier to manage.
 	"getrandom",
 
-	# Pull in `rand` for `ThreadRng`.
-	"dep:rand",
-
 	"aes-gcm/std",
 	"aranya-buggy/std",
 	"crypto-common/std",

diff --git a/crates/aranya-crypto-core/src/csprng.rs b/crates/aranya-crypto-core/src/csprng.rs
@@ -46,16 +46,16 @@ impl<R: Csprng + ?Sized> Csprng for &mut R {
     }
 }
 
-#[cfg(feature = "getrandom")]
-#[cfg_attr(docsrs, doc(cfg(feature = "getrandom")))]
+#[cfg(all(feature = "getrandom", feature = "rand_compat"))]
+#[cfg_attr(docsrs, doc(cfg(all(feature = "getrandom", feature = "rand_compat"))))]
 impl Csprng for rand_core::OsRng {
     fn fill_bytes(&mut self, dst: &mut [u8]) {
         rand_core::RngCore::fill_bytes(self, dst)
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(all(feature = "rand_compat", feature = "std"))]
+#[cfg_attr(docsrs, doc(cfg(all(feature = "rand_compat", feature = "std"))))]
 impl Csprng for rand::rngs::ThreadRng {
     fn fill_bytes(&mut self, dst: &mut [u8]) {
         rand_core::RngCore::fill_bytes(self, dst)

diff --git a/crates/aranya-crypto-core/src/default.rs b/crates/aranya-crypto-core/src/default.rs
@@ -9,14 +9,12 @@ use crate::csprng::Csprng;
 /// Certain feature flags will change the default CSPRNG:
 ///
 /// - `trng`: Uses a TRNG provided by the system.
-/// - `std`: Uses a thread-local CSPRNG seeded from the system
-///   CSPRNG.
-/// - `libc`: Uses the system CSPRNG.
+/// - `getrandom`: Uses the system CSPRNG.
 ///
-/// The `libc` flag is enabled by default.
+/// The `getrandom` flag is enabled by default.
 ///
-/// If all of those feature flags are disabled, `Rng` invokes the
-/// following routine:
+/// If none of those feature flags are disabled, `Rng` invokes
+/// the following routine:
 ///
 /// ```
 /// extern "C" {
@@ -56,9 +54,6 @@ impl Csprng for Rng {
         cfg_if! {
             if #[cfg(feature = "trng")] {
                 crate::csprng::trng::thread_rng().fill_bytes(dst)
-            } else if #[cfg(feature = "std")] {
-                // Try to use `ThreadRng` if possible.
-                rand_core::RngCore::fill_bytes(&mut rand::thread_rng(), dst)
             } else if #[cfg(feature = "getrandom")] {
                 getrandom::getrandom(dst).expect("should not fail")
             } else {
@@ -75,9 +70,11 @@ impl Csprng for Rng {
 }
 
 #[cfg(feature = "rand_compat")]
+#[cfg_attr(docsrs, doc(cfg(feature = "rand_compat")))]
 impl rand_core::CryptoRng for Rng {}
 
 #[cfg(feature = "rand_compat")]
+#[cfg_attr(docsrs, doc(cfg(feature = "rand_compat")))]
 impl rand_core::RngCore for Rng {
     fn next_u32(&mut self) -> u32 {
         rand_core::impls::next_u32_via_fill(self)