diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 8400cf63..fdf6b999 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -73,7 +73,7 @@ jobs:
         git clone https://github.com/Chia-Network/clvm_tools.git --branch=main --single-branch
         python -m pip install ./clvm_tools
         python -m pip install colorama
-        maturin develop --release
+        maturin develop --release --cargo-extra-args="--features=openssl"
 
     - name: Run benchmarks
       if: ${{ !startsWith(matrix.os, 'windows') }}
@@ -119,7 +119,7 @@ jobs:
         git clone https://github.com/Chia-Network/clvm_tools.git --branch=main --single-branch
         python -m pip install ./clvm_tools
         python -m pip install colorama
-        maturin develop --release
+        maturin develop --release --cargo-extra-args="--features=openssl"
 
     - name: Run cost checks
       run: |
diff --git a/.github/workflows/build-arm64-wheels.yml b/.github/workflows/build-arm64-wheels.yml
index 0e8a3587..cb40a22f 100644
--- a/.github/workflows/build-arm64-wheels.yml
+++ b/.github/workflows/build-arm64-wheels.yml
@@ -52,7 +52,7 @@ jobs:
             if [ ! -f "activate" ]; then ln -s venv/bin/activate; fi && \
             . ./activate && \
             pip install maturin && \
-            CC=gcc maturin build --no-sdist --release --strip --manylinux 2014 \
+            CC=gcc maturin build --no-sdist --release --strip --manylinux 2014 --cargo-extra-args="--features=openssl" \
           '
 
     - name: Upload artifacts
diff --git a/.github/workflows/build-m1-wheel.yml b/.github/workflows/build-m1-wheel.yml
index d338a6a3..941d538e 100644
--- a/.github/workflows/build-m1-wheel.yml
+++ b/.github/workflows/build-m1-wheel.yml
@@ -43,7 +43,7 @@ jobs:
         . ./venv/bin/activate
         export PATH=~/.cargo/bin:$PATH
         arch -arm64 pip install maturin
-        arch -arm64 maturin build --no-sdist -i python --release --strip
+        arch -arm64 maturin build --no-sdist -i python --release --strip --cargo-extra-args="--features=openssl"
 
     - name: Install clvm_rs wheel
       run: |
diff --git a/.github/workflows/build-test.yml b/.github/workflows/build-test.yml
index 45598e30..fbb7cedc 100644
--- a/.github/workflows/build-test.yml
+++ b/.github/workflows/build-test.yml
@@ -50,7 +50,7 @@ jobs:
         python -m venv venv
         ln -s venv/bin/activate
         . ./activate
-        maturin build --no-sdist -i python --release --strip
+        maturin build --no-sdist -i python --release --strip --cargo-extra-args="--features=openssl"
 
 #    - name: Build Linux with maturin on Python ${{ matrix.python }}
 #      if: startsWith(matrix.os, 'ubuntu')
@@ -86,7 +86,7 @@ jobs:
             . ./activate && \
             pip install --upgrade pip && \
             pip install maturin && \
-            CC=gcc maturin build --no-sdist --release --strip --manylinux 2010 \
+            CC=gcc maturin build --no-sdist --release --strip --manylinux 2010 --cargo-extra-args="--features=openssl" \
           '
 
     - name: Build Windows with maturin on Python ${{ matrix.python }}
diff --git a/Cargo.toml b/Cargo.toml
index e781c50c..24d25a14 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,11 +27,8 @@ num-bigint = "=0.4.0"
 num-traits = "=0.2.14"
 num-integer = "=0.1.44"
 bls12_381 = "=0.5.0"
-
 sha2 = "=0.9.5"
-
-[target.'cfg(unix)'.dependencies]
-openssl = { version = "0.10.35", features = ["vendored"] }
+openssl = { version = "0.10.35", features = ["vendored"], optional = true }
 
 [target.'cfg(target_family="wasm")'.dependencies]
 wasm-bindgen = "=0.2.75"
diff --git a/README.md b/README.md
index 8c1ea919..5c79363e 100644
--- a/README.md
+++ b/README.md
@@ -15,12 +15,26 @@ Build `clvm_rs` directly into the current virtualenv with
 $ maturin develop --release
 ```
 
+On UNIX-based platforms, you may get a speed boost on `sha256` operations by building
+with OpenSSL.
+
+```
+$ maturin develop --release --cargo-extra-args="--features=openssl"
+```
+
+
 To build the wheel, do
 
 ```
 $ maturin build --release --no-sdist
 ````
 
+or
+
+```
+$ maturin build --release --no-sdist --cargo-extra-args="--features=openssl"
+```
+
 
 WASM
 ----
@@ -34,7 +48,7 @@ $ cargo install wasm-pack
 Then build with
 
 ```
-$ wasm-pack build  --release
+$ wasm-pack build --release
 ```
 
 
diff --git a/src/sha2.rs b/src/sha2.rs
index a3966ee9..bf45d393 100644
--- a/src/sha2.rs
+++ b/src/sha2.rs
@@ -1,18 +1,18 @@
-#[cfg(not(unix))]
+#[cfg(not(openssl))]
 use sha2::{Digest, Sha256 as Ctx};
 
-#[cfg(unix)]
+#[cfg(openssl)]
 use openssl::sha;
 
 // WINDOWS PART
 
-#[cfg(not(unix))]
+#[cfg(not(openssl))]
 #[derive(Clone)]
 pub struct Sha256 {
     ctx: Ctx,
 }
 
-#[cfg(not(unix))]
+#[cfg(not(openssl))]
 impl Sha256 {
     pub fn new() -> Sha256 {
         Sha256 { ctx: Ctx::new() }
@@ -25,15 +25,15 @@ impl Sha256 {
     }
 }
 
-// UNIX PART
+// OPENSSL PART
 
-#[cfg(unix)]
+#[cfg(openssl)]
 #[derive(Clone)]
 pub struct Sha256 {
     ctx: sha::Sha256,
 }
 
-#[cfg(unix)]
+#[cfg(openssl)]
 impl Sha256 {
     pub fn new() -> Sha256 {
         Sha256 {