diff --git a/Cargo.toml b/Cargo.toml
index 6442c18945..87b8e71ab3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -76,7 +76,7 @@ exclude = ["benches", "distr_test"]
 rand_core = { version = "0.10.0-rc-2", default-features = false }
 log = { version = "0.4.4", optional = true }
 serde = { version = "1.0.103", features = ["derive"], optional = true }
-chacha20 = { version = "=0.10.0-rc.5", default-features = false, features = ["rng"], optional = true }
+chacha20 = { path = "rand_chacha", optional = true, package = "rand_chacha" }
 getrandom = { version = "0.3.0", optional = true }
 
 [dev-dependencies]
@@ -85,3 +85,6 @@ rand_pcg = { path = "rand_pcg", version = "0.10.0-rc.1" }
 bincode = "1.2.1"
 rayon = "1.7"
 serde_json = "1.0.140"
+
+[patch.crates-io]
+rand_core = { git = "https://github.com/rust-random/rand_core.git", branch = "reduce-block-code" }
diff --git a/benches/Cargo.toml b/benches/Cargo.toml
index 699186b26f..83d8e0c327 100644
--- a/benches/Cargo.toml
+++ b/benches/Cargo.toml
@@ -56,3 +56,6 @@ harness = false
 [[bench]]
 name = "weighted"
 harness = false
+
+[patch.crates-io]
+rand_core = { git = "https://github.com/rust-random/rand_core.git", branch = "reduce-block-code" }
diff --git a/rand_chacha/src/chacha.rs b/rand_chacha/src/chacha.rs
index f42232f757..a455f0123c 100644
--- a/rand_chacha/src/chacha.rs
+++ b/rand_chacha/src/chacha.rs
@@ -10,7 +10,7 @@
 
 use crate::guts::ChaCha;
 use core::fmt;
-use rand_core::block::{BlockRng, BlockRngCore, CryptoBlockRng};
+use rand_core::block::{BlockRng, CryptoGenerator, Generator};
 use rand_core::{CryptoRng, RngCore, SeedableRng};
 
 #[cfg(feature = "serde")]
@@ -21,52 +21,6 @@ const BUF_BLOCKS: u8 = 4;
 // number of 32-bit words per ChaCha block (fixed by algorithm definition)
 const BLOCK_WORDS: u8 = 16;
 
-#[repr(transparent)]
-pub struct Array64<T>([T; 64]);
-impl<T> Default for Array64<T>
-where
-    T: Default,
-{
-    #[rustfmt::skip]
-    fn default() -> Self {
-        Self([
-            T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
-            T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
-            T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
-            T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
-            T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
-            T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
-            T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
-            T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
-        ])
-    }
-}
-impl<T> AsRef<[T]> for Array64<T> {
-    fn as_ref(&self) -> &[T] {
-        &self.0
-    }
-}
-impl<T> AsMut<[T]> for Array64<T> {
-    fn as_mut(&mut self) -> &mut [T] {
-        &mut self.0
-    }
-}
-impl<T> Clone for Array64<T>
-where
-    T: Copy + Default,
-{
-    fn clone(&self) -> Self {
-        let mut new = Self::default();
-        new.0.copy_from_slice(&self.0);
-        new
-    }
-}
-impl<T> fmt::Debug for Array64<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Array64 {{}}")
-    }
-}
-
 macro_rules! chacha_impl {
     ($ChaChaXCore:ident, $ChaChaXRng:ident, $rounds:expr, $doc:expr, $abst:ident,) => {
         #[doc=$doc]
@@ -82,13 +36,12 @@ macro_rules! chacha_impl {
             }
         }
 
-        impl BlockRngCore for $ChaChaXCore {
-            type Item = u32;
-            type Results = Array64<u32>;
+        impl Generator for $ChaChaXCore {
+            type Output = [u32; 64];
 
             #[inline]
-            fn generate(&mut self, r: &mut Self::Results) {
-                self.state.refill4($rounds, &mut r.0);
+            fn generate(&mut self, output: &mut Self::Output) {
+                self.state.refill4($rounds, output);
             }
         }
 
@@ -103,7 +56,7 @@ macro_rules! chacha_impl {
             }
         }
 
-        impl CryptoBlockRng for $ChaChaXCore {}
+        impl CryptoGenerator for $ChaChaXCore {}
 
         /// A cryptographically secure random number generator that uses the ChaCha algorithm.
         ///
@@ -163,12 +116,12 @@ macro_rules! chacha_impl {
         impl RngCore for $ChaChaXRng {
             #[inline]
             fn next_u32(&mut self) -> u32 {
-                self.rng.next_u32()
+                self.rng.next_word()
             }
 
             #[inline]
             fn next_u64(&mut self) -> u64 {
-                self.rng.next_u64()
+                self.rng.next_u64_from_u32()
             }
 
             #[inline]
diff --git a/src/rngs/reseeding.rs b/src/rngs/reseeding.rs
index 4a9f107edb..47f449d9be 100644
--- a/src/rngs/reseeding.rs
+++ b/src/rngs/reseeding.rs
@@ -12,10 +12,10 @@
 
 use core::mem::size_of_val;
 
-use rand_core::block::{BlockRng, BlockRngCore, CryptoBlockRng};
+use rand_core::block::{BlockRng, CryptoGenerator, Generator};
 use rand_core::{CryptoRng, RngCore, SeedableRng, TryCryptoRng, TryRngCore};
 
-/// A wrapper around any PRNG that implements [`BlockRngCore`], that adds the
+/// A wrapper around any PRNG that implements [`Generator`], that adds the
 /// ability to reseed it.
 ///
 /// `ReseedingRng` reseeds the underlying PRNG in the following cases:
@@ -53,7 +53,7 @@ use rand_core::{CryptoRng, RngCore, SeedableRng, TryCryptoRng, TryRngCore};
 ///
 /// ```
 /// use chacha20::ChaCha20Core; // Internal part of ChaChaRng that
-///                             // implements BlockRngCore
+///                             // implements Generator
 /// use rand::prelude::*;
 /// use rand::rngs::OsRng;
 /// use rand::rngs::ReseedingRng;
@@ -63,18 +63,18 @@ use rand_core::{CryptoRng, RngCore, SeedableRng, TryCryptoRng, TryRngCore};
 /// println!("{}", reseeding_rng.random::<u64>());
 /// ```
 ///
-/// [`BlockRngCore`]: rand_core::block::BlockRngCore
+/// [`Generator`]: rand_core::block::Generator
 /// [`ReseedingRng::new`]: ReseedingRng::new
 /// [`reseed()`]: ReseedingRng::reseed
 #[derive(Debug)]
-pub struct ReseedingRng<R, Rsdr>(BlockRng<ReseedingCore<R, Rsdr>>)
+pub struct ReseedingRng<G, Rsdr>(BlockRng<ReseedingCore<G, Rsdr>>)
 where
-    R: BlockRngCore + SeedableRng,
+    G: Generator + SeedableRng,
     Rsdr: TryRngCore;
 
-impl<R, Rsdr> ReseedingRng<R, Rsdr>
+impl<const N: usize, G, Rsdr> ReseedingRng<G, Rsdr>
 where
-    R: BlockRngCore + SeedableRng,
+    G: Generator<Output = [u32; N]> + SeedableRng,
     Rsdr: TryRngCore,
 {
     /// Create a new `ReseedingRng` from an existing PRNG, combined with a RNG
@@ -100,19 +100,19 @@ where
 
 // TODO: this should be implemented for any type where the inner type
 // implements RngCore, but we can't specify that because ReseedingCore is private
-impl<R, Rsdr> RngCore for ReseedingRng<R, Rsdr>
+impl<const N: usize, G, Rsdr> RngCore for ReseedingRng<G, Rsdr>
 where
-    R: BlockRngCore<Item = u32> + SeedableRng,
+    G: Generator<Output = [u32; N]> + SeedableRng,
     Rsdr: TryRngCore,
 {
     #[inline(always)]
     fn next_u32(&mut self) -> u32 {
-        self.0.next_u32()
+        self.0.next_word()
     }
 
     #[inline(always)]
     fn next_u64(&mut self) -> u64 {
-        self.0.next_u64()
+        self.0.next_u64_from_u32()
     }
 
     fn fill_bytes(&mut self, dest: &mut [u8]) {
@@ -120,51 +120,50 @@ where
     }
 }
 
-impl<R, Rsdr> CryptoRng for ReseedingRng<R, Rsdr>
+impl<const N: usize, G, Rsdr> CryptoRng for ReseedingRng<G, Rsdr>
 where
-    R: BlockRngCore<Item = u32> + SeedableRng + CryptoBlockRng,
+    G: Generator<Output = [u32; N]> + SeedableRng + CryptoGenerator,
     Rsdr: TryCryptoRng,
 {
 }
 
 #[derive(Debug)]
-struct ReseedingCore<R, Rsdr> {
-    inner: R,
+struct ReseedingCore<G, Rsdr> {
+    inner: G,
     reseeder: Rsdr,
     threshold: i64,
     bytes_until_reseed: i64,
 }
 
-impl<R, Rsdr> BlockRngCore for ReseedingCore<R, Rsdr>
+impl<G, Rsdr> Generator for ReseedingCore<G, Rsdr>
 where
-    R: BlockRngCore + SeedableRng,
+    G: Generator + SeedableRng,
     Rsdr: TryRngCore,
 {
-    type Item = <R as BlockRngCore>::Item;
-    type Results = <R as BlockRngCore>::Results;
+    type Output = <G as Generator>::Output;
 
-    fn generate(&mut self, results: &mut Self::Results) {
+    fn generate(&mut self, results: &mut Self::Output) {
         if self.bytes_until_reseed <= 0 {
             // We get better performance by not calling only `reseed` here
             // and continuing with the rest of the function, but by directly
             // returning from a non-inlined function.
             return self.reseed_and_generate(results);
         }
-        let num_bytes = size_of_val(results.as_ref());
+        let num_bytes = size_of_val(results);
         self.bytes_until_reseed -= num_bytes as i64;
         self.inner.generate(results);
     }
 }
 
-impl<R, Rsdr> ReseedingCore<R, Rsdr>
+impl<G, Rsdr> ReseedingCore<G, Rsdr>
 where
-    R: BlockRngCore + SeedableRng,
+    G: Generator + SeedableRng,
     Rsdr: TryRngCore,
 {
     /// Create a new `ReseedingCore`.
     ///
     /// `threshold` is the maximum number of bytes produced by
-    /// [`BlockRngCore::generate`] before attempting reseeding.
+    /// [`Generator::generate`] before attempting reseeding.
     fn new(threshold: u64, mut reseeder: Rsdr) -> Result<Self, Rsdr::Error> {
         // Because generating more values than `i64::MAX` takes centuries on
         // current hardware, we just clamp to that value.
@@ -178,7 +177,7 @@ where
             i64::MAX
         };
 
-        let inner = R::try_from_rng(&mut reseeder)?;
+        let inner = G::try_from_rng(&mut reseeder)?;
 
         Ok(ReseedingCore {
             inner,
@@ -190,17 +189,17 @@ where
 
     /// Reseed the internal PRNG.
     fn reseed(&mut self) -> Result<(), Rsdr::Error> {
-        R::try_from_rng(&mut self.reseeder).map(|result| {
+        G::try_from_rng(&mut self.reseeder).map(|result| {
             self.bytes_until_reseed = self.threshold;
             self.inner = result
         })
     }
 
     #[inline(never)]
-    fn reseed_and_generate(&mut self, results: &mut <Self as BlockRngCore>::Results) {
+    fn reseed_and_generate(&mut self, results: &mut G::Output) {
         trace!("Reseeding RNG (periodic reseed)");
 
-        let num_bytes = size_of_val(results.as_ref());
+        let num_bytes = size_of_val(results);
 
         if let Err(e) = self.reseed() {
             warn!("Reseeding RNG failed: {}", e);
@@ -212,9 +211,9 @@ where
     }
 }
 
-impl<R, Rsdr> CryptoBlockRng for ReseedingCore<R, Rsdr>
+impl<G, Rsdr> CryptoGenerator for ReseedingCore<G, Rsdr>
 where
-    R: BlockRngCore<Item = u32> + SeedableRng + CryptoBlockRng,
+    G: Generator + SeedableRng + CryptoGenerator,
     Rsdr: TryCryptoRng,
 {
 }