diff --git a/crates/tarball/src/lib.rs b/crates/tarball/src/lib.rs
index c182ff4a..fc4571c0 100644
--- a/crates/tarball/src/lib.rs
+++ b/crates/tarball/src/lib.rs
@@ -17,7 +17,7 @@ use pacquet_store_dir::{
 };
 use pipe_trait::Pipe;
 use reqwest::Client;
-use ssri::{Integrity, IntegrityChecker};
+use ssri::Integrity;
 use tar::Archive;
 use tokio::sync::{Notify, RwLock};
 use tracing::instrument;
@@ -103,11 +103,6 @@ fn decompress_gzip(gz_data: &[u8], unpacked_size: Option<usize>) -> Result<Vec<u
         .map_err(TarballError::DecodeGzip)
 }
 
-#[instrument(skip(data), fields(data_len = data.len()))]
-fn verify_checksum(data: &[u8], integrity: Integrity) -> Result<ssri::Algorithm, ssri::Error> {
-    integrity.pipe(IntegrityChecker::new).chain(data).result()
-}
-
 /// This subroutine downloads and extracts a tarball to the store directory.
 ///
 /// It returns a CAS map of files in the tarball.
@@ -200,8 +195,8 @@ impl<'a> DownloadTarballToStore<'a> {
             Checksum(ssri::Error),
             Other(TarballError),
         }
-        let cas_paths = tokio::task::spawn(async move {
-            verify_checksum(&response, package_integrity.clone()).map_err(TaskError::Checksum)?;
+        let cas_paths = tokio::task::spawn_blocking(move || {
+            package_integrity.check(&response).map_err(TaskError::Checksum)?;
 
             // TODO: move tarball extraction to its own function
             // TODO: test it