diff --git a/.cargo-deny.toml b/.cargo-deny.toml
index 3429018..0b91841 100644
--- a/.cargo-deny.toml
+++ b/.cargo-deny.toml
@@ -22,6 +22,8 @@ allow = [
   "CDLA-Permissive-2.0",
   "ISC",
   "MIT",
+  "MPL-2.0",
+  "Unicode-3.0",
   "Zlib",
 ]
 private = { ignore = false }
diff --git a/rust/Cargo.lock b/rust/Cargo.lock
index 36fbde4..edc9d92 100644
--- a/rust/Cargo.lock
+++ b/rust/Cargo.lock
@@ -51,6 +51,27 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "dirs"
+version = "6.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3e8aa94d75141228480295a7d0e7feb620b1a5ad9f12bc40be62411e38cce4e"
+dependencies = [
+ "dirs-sys",
+]
+
+[[package]]
+name = "dirs-sys"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e01a3366d27ee9890022452ee61b2b63a67e6f13f58900b651ff5665f0bb1fab"
+dependencies = [
+ "libc",
+ "option-ext",
+ "redox_users",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "errno"
 version = "0.3.14"
@@ -58,7 +79,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -155,6 +176,7 @@ checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
 name = "logos-blockchain-circuits-build"
 version = "0.5.0"
 dependencies = [
+ "dirs",
  "flate2",
  "tar",
  "ureq",
@@ -227,6 +249,12 @@ version = "1.21.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"
 
+[[package]]
+name = "option-ext"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "04744f49eae99ab78e0d5c0b603ab218f515ea8cfe5a456d7629ad883a3b6e7d"
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.2"
@@ -239,6 +267,24 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b4596b6d070b27117e987119b4dac604f3c58cfb0b191112e24771b2faeac1a6"
 
+[[package]]
+name = "proc-macro2"
+version = "1.0.106"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fd00f0bb2e90d81d1044c2b32617f68fcb9fa3bb7640c23e9c748e53fb30934"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41f2619966050689382d2b44f664f4bc593e129785a36d6ee376ddf37259b924"
+dependencies = [
+ "proc-macro2",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.7.4"
@@ -248,6 +294,17 @@ dependencies = [
  "bitflags",
 ]
 
+[[package]]
+name = "redox_users"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4e608c6638b9c18977b00b475ac1f28d14e84b27d8d42f70e0bf1e3dec127ac"
+dependencies = [
+ "getrandom",
+ "libredox",
+ "thiserror",
+]
+
 [[package]]
 name = "ring"
 version = "0.17.14"
@@ -259,7 +316,7 @@ dependencies = [
  "getrandom",
  "libc",
  "untrusted",
- "windows-sys",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -272,7 +329,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -328,6 +385,17 @@ version = "2.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
 
+[[package]]
+name = "syn"
+version = "2.0.117"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e665b8803e7b1d2a727f4023456bbbbe74da67099c585258af0ad9c5013b9b99"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "tar"
 version = "0.4.45"
@@ -339,6 +407,32 @@ dependencies = [
  "xattr",
 ]
 
+[[package]]
+name = "thiserror"
+version = "2.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4288b5bcbc7920c07a1149a35cf9590a2aa808e0bc1eafaade0b80947865fbc4"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ebc4ee7f67670e9b64d05fa4253e753e016c6c95ff35b89b7941d6b856dec1d5"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
+
 [[package]]
 name = "untrusted"
 version = "0.9.0"
@@ -395,6 +489,12 @@ dependencies = [
  "rustls-pki-types",
 ]
 
+[[package]]
+name = "windows-link"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+
 [[package]]
 name = "windows-sys"
 version = "0.52.0"
@@ -404,6 +504,15 @@ dependencies = [
  "windows-targets",
 ]
 
+[[package]]
+name = "windows-sys"
+version = "0.61.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+dependencies = [
+ "windows-link",
+]
+
 [[package]]
 name = "windows-targets"
 version = "0.52.6"
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index e91f7bc..68d5c41 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -31,6 +31,7 @@ lbc-signature-sys = { default-features = false, package = "logos-blockchain-circ
 lbc-types = { default-features = false, package = "logos-blockchain-circuits-types", path = "./logos-blockchain-circuits-types" }
 
 # External
+dirs = "^6"
 flate2 = "^1.1"
 libc = "^0.2"
 tar = "^0.4"
diff --git a/rust/logos-blockchain-circuits-build/Cargo.toml b/rust/logos-blockchain-circuits-build/Cargo.toml
index fff522c..bd03025 100644
--- a/rust/logos-blockchain-circuits-build/Cargo.toml
+++ b/rust/logos-blockchain-circuits-build/Cargo.toml
@@ -9,10 +9,14 @@ readme.workspace = true
 repository.workspace = true
 version.workspace = true
 
+[features]
+prebuilt = ["dep:dirs", "dep:flate2", "dep:tar", "dep:ureq"]
+
 [lints]
 workspace = true
 
 [dependencies]
-flate2 = { workspace = true }
-tar = { workspace = true }
-ureq = { workspace = true }
+dirs = { workspace = true, optional = true }
+flate2 = { workspace = true, optional = true }
+tar = { workspace = true, optional = true }
+ureq = { workspace = true, optional = true }
diff --git a/rust/logos-blockchain-circuits-build/src/lib.rs b/rust/logos-blockchain-circuits-build/src/lib.rs
index 9e8909e..205dfd7 100644
--- a/rust/logos-blockchain-circuits-build/src/lib.rs
+++ b/rust/logos-blockchain-circuits-build/src/lib.rs
@@ -1,80 +1,102 @@
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 
-use ureq::Body;
-use ureq::http::Response;
+#[cfg(feature = "prebuilt")]
+mod prebuilt {
+    use std::path::{Path, PathBuf};
+    use ureq::Body;
+    use ureq::http::Response;
 
-static REPO: &str = "logos-blockchain/logos-blockchain-circuits";
-static ARTIFACT_PREFIX: &str = "logos-blockchain-circuits";
+    static REPO: &str = "logos-blockchain/logos-blockchain-circuits";
+    static ARTIFACT_PREFIX: &str = "logos-blockchain-circuits";
 
-fn build_artifact_name(version: &str, os: &str, arch: &str) -> String {
-    format!("{ARTIFACT_PREFIX}-v{version}-{os}-{arch}")
-}
-
-fn build_artifact_url(version: &str, os: &str, arch: &str) -> String {
-    let artifact = build_artifact_name(version, os, arch);
-    let artifact_tar_gz = format!("{artifact}.tar.gz");
-    format!("https://github.com/{REPO}/releases/download/v{version}/{artifact_tar_gz}")
-}
-
-fn fetch_library(version: &str, os: &str, arch: &str, lib_var_name: &str) -> Response<Body> {
-    let url = build_artifact_url(version, os, arch);
-    // We skip checksum verification intentionally.
-    // Hardcoded hashes would protect against a silently replaced release asset, but require a
-    // two-step release (build → hash → commit → tag) which feels overkill for a first-party
-    // library.
-    ureq::get(&url).call().unwrap_or_else(|error| {
-        panic!(
-            "Failed to download a prebuilt library for {os}-{arch} v{version}: {error}. \
-             Set {lib_var_name} to point to a local build instead."
-        )
-    })
-}
-
-fn unpack_library(
-    response: Response<Body>,
-    circuit_name: &str,
-    version: &str,
-    os: &str,
-    arch: &str,
-    output_dir: &Path,
-) -> PathBuf {
-    let gz_decoder = flate2::read::GzDecoder::new(response.into_body().into_reader());
-    let mut archive = tar::Archive::new(gz_decoder);
-    archive
-        .unpack(output_dir)
-        .expect("Failed to unpack the downloaded archive.");
-
-    let unpacked_artifact_path = output_dir.join(build_artifact_name(version, os, arch));
-    let unpacked_library_directory = unpacked_artifact_path.join(circuit_name);
-
-    assert!(
-        unpacked_library_directory.is_dir(),
-        "Failed to find the unpacked library at {}",
-        unpacked_library_directory.display()
-    );
-
-    unpacked_library_directory
-}
-
-fn provision_library(circuit_name: &str, lib_var_name: &str) -> PathBuf {
-    let version = env!("CARGO_PKG_VERSION");
-    let os = std::env::var("CARGO_CFG_TARGET_OS").unwrap();
-    let arch = std::env::var("CARGO_CFG_TARGET_ARCH").unwrap();
-    let out_dir = PathBuf::from(std::env::var("OUT_DIR").unwrap());
-
-    let expected_library_directory = out_dir
-        .join(build_artifact_name(version, &os, &arch))
-        .join(circuit_name);
-    if expected_library_directory.is_dir() {
-        println!(
-            "Found an existing library at {}. Reusing it.",
-            expected_library_directory.display()
-        );
-        return expected_library_directory;
+    fn build_artifact_name(version: &str, os: &str, arch: &str) -> String {
+        format!("{ARTIFACT_PREFIX}-v{version}-{os}-{arch}")
     }
 
-    let response = fetch_library(version, &os, &arch, lib_var_name);
-    unpack_library(response, circuit_name, version, &os, &arch, &out_dir)
+    fn build_artifact_url(version: &str, os: &str, arch: &str) -> String {
+        let artifact = build_artifact_name(version, os, arch);
+        let artifact_tar_gz = format!("{artifact}.tar.gz");
+        format!("https://github.com/{REPO}/releases/download/v{version}/{artifact_tar_gz}")
+    }
+
+    fn fetch_library(version: &str, os: &str, arch: &str, lib_var_name: &str) -> Response<Body> {
+        let url = build_artifact_url(version, os, arch);
+        // We skip checksum verification intentionally.
+        // Hardcoded hashes would protect against a silently replaced release asset but require a
+        // two-step release (build → hash → commit → tag) which feels overkill for a first-party
+        // library.
+        ureq::get(&url).call().unwrap_or_else(|error| {
+            panic!(
+                "Failed to download a prebuilt library for {os}-{arch} v{version}: {error}. \
+                 Set {lib_var_name} to point to a local build instead."
+            )
+        })
+    }
+
+    fn unpack_library(
+        response: Response<Body>,
+        circuit_name: &str,
+        version: &str,
+        os: &str,
+        arch: &str,
+        output_dir: &Path,
+    ) -> PathBuf {
+        let gz_decoder = flate2::read::GzDecoder::new(response.into_body().into_reader());
+        let mut archive = tar::Archive::new(gz_decoder);
+        archive
+            .unpack(output_dir)
+            .expect("Failed to unpack the downloaded archive.");
+
+        let unpacked_artifact_path = output_dir.join(build_artifact_name(version, os, arch));
+        let unpacked_library_directory = unpacked_artifact_path.join(circuit_name);
+
+        assert!(
+            unpacked_library_directory.is_dir(),
+            "Failed to find the unpacked library at {}",
+            unpacked_library_directory.display()
+        );
+
+        unpacked_library_directory
+    }
+
+    fn cache_dir() -> PathBuf {
+        dirs::cache_dir()
+            .expect("Could not determine the cache directory for this platform.")
+            .join("logos")
+            .join("blockchain")
+    }
+
+    pub fn provision_library(circuit_name: &str, lib_var_name: &str) -> PathBuf {
+        let version = env!("CARGO_PKG_VERSION");
+        let os = std::env::var("CARGO_CFG_TARGET_OS").unwrap();
+        let arch = std::env::var("CARGO_CFG_TARGET_ARCH").unwrap();
+
+        let cache = cache_dir();
+        // The tarball unpacks to a top-level `{artifact_name}/` dir, so the circuit lives at
+        // `cache/{artifact_name}/{circuit_name}/`.
+        let circuit_dir = cache
+            .join(build_artifact_name(version, &os, &arch))
+            .join(circuit_name);
+
+        if circuit_dir.is_dir() {
+            println!(
+                "Found a cached {circuit_name} library at {}, reusing.",
+                circuit_dir.display()
+            );
+            return circuit_dir;
+        }
+
+        std::fs::create_dir_all(&cache).expect("Failed to create cache directory.");
+
+        println!(
+            "No cached download found, downloading {circuit_name} v{version} for {os}-{arch}..."
+        );
+        let response = fetch_library(version, &os, &arch, lib_var_name);
+        println!("Download complete, unpacking...");
+        let lib_dir = unpack_library(response, circuit_name, version, &os, &arch, &cache);
+        println!("Ready, {circuit_name} library at {}.", lib_dir.display());
+        lib_dir
+    }
 }
 
 pub fn build(circuit_name: &str, lib_var_name: &str) {
@@ -84,9 +106,22 @@ pub fn build(circuit_name: &str, lib_var_name: &str) {
     println!("cargo:rerun-if-changed=build.rs");
 
     let lib_dir = std::env::var(lib_var_name).map_or_else(
-        |_| provision_library(circuit_name, lib_var_name),
+        |_| {
+            #[cfg(not(feature = "prebuilt"))]
+            panic!(
+                "{lib_var_name} is not set. Either:\n\
+                 - Set {lib_var_name} to point at a local build, or\n\
+                 - Enable the `prebuilt` feature to download from GitHub Releases."
+            );
+
+            #[cfg(feature = "prebuilt")]
+            {
+                println!("{lib_var_name} not set, falling back to prebuilt download.");
+                prebuilt::provision_library(circuit_name, lib_var_name)
+            }
+        },
         |lib_dir| {
-            println!("Using a library directory from {lib_var_name}: {lib_dir}");
+            println!("Found {lib_var_name}, using local library at {lib_dir}.");
             let lib_dir_path = PathBuf::from(lib_dir);
             assert!(
                 lib_dir_path.is_dir(),
diff --git a/rust/logos-blockchain-circuits-poc-sys/Cargo.toml b/rust/logos-blockchain-circuits-poc-sys/Cargo.toml
index 01fa797..a3824ed 100644
--- a/rust/logos-blockchain-circuits-poc-sys/Cargo.toml
+++ b/rust/logos-blockchain-circuits-poc-sys/Cargo.toml
@@ -9,6 +9,9 @@ readme.workspace = true
 repository.workspace = true
 version.workspace = true
 
+[features]
+prebuilt = ["lbc-build/prebuilt"]
+
 [lints]
 workspace = true
 
diff --git a/rust/logos-blockchain-circuits-pol-sys/Cargo.toml b/rust/logos-blockchain-circuits-pol-sys/Cargo.toml
index 7bb520e..08481ff 100644
--- a/rust/logos-blockchain-circuits-pol-sys/Cargo.toml
+++ b/rust/logos-blockchain-circuits-pol-sys/Cargo.toml
@@ -9,6 +9,9 @@ readme.workspace = true
 repository.workspace = true
 version.workspace = true
 
+[features]
+prebuilt = ["lbc-build/prebuilt"]
+
 [lints]
 workspace = true
 
diff --git a/rust/logos-blockchain-circuits-poq-sys/Cargo.toml b/rust/logos-blockchain-circuits-poq-sys/Cargo.toml
index d3b8324..3e29099 100644
--- a/rust/logos-blockchain-circuits-poq-sys/Cargo.toml
+++ b/rust/logos-blockchain-circuits-poq-sys/Cargo.toml
@@ -9,6 +9,9 @@ readme.workspace = true
 repository.workspace = true
 version.workspace = true
 
+[features]
+prebuilt = ["lbc-build/prebuilt"]
+
 [lints]
 workspace = true
 
diff --git a/rust/logos-blockchain-circuits-signature-sys/Cargo.toml b/rust/logos-blockchain-circuits-signature-sys/Cargo.toml
index 0a4ec14..04c3e14 100644
--- a/rust/logos-blockchain-circuits-signature-sys/Cargo.toml
+++ b/rust/logos-blockchain-circuits-signature-sys/Cargo.toml
@@ -9,6 +9,9 @@ readme.workspace = true
 repository.workspace = true
 version.workspace = true
 
+[features]
+prebuilt = ["lbc-build/prebuilt"]
+
 [lints]
 workspace = true