diff --git a/src/client/http_client.rs b/src/client/http_client.rs
index 6718bf26..281ba4ff 100644
--- a/src/client/http_client.rs
+++ b/src/client/http_client.rs
@@ -708,7 +708,7 @@ impl BackupClient {
             .and_then(move |res| {
                 let wid = res.as_u64().unwrap();
                 Self::upload_chunk_info_stream(h2_3, wid, stream, &prefix, known_chunks.clone(), crypt_config)
-                    .and_then(move |(chunk_count, size, _speed)| {
+                    .and_then(move |(chunk_count, size, _speed, csum)| {
                         let param = json!({
                             "wid": wid ,
                             "chunk-count": chunk_count,
@@ -716,7 +716,7 @@ impl BackupClient {
                         });
                         h2_4.post(&close_path, Some(param))
                             .map(move |_| {
-                                BackupStats { size: size as u64, csum: [0u8; 32] }
+                                BackupStats { size: size as u64, csum }
                             })
                     })
             })
@@ -865,7 +865,7 @@ impl BackupClient {
         prefix: &str,
         known_chunks: Arc<Mutex<HashSet<[u8;32]>>>,
         crypt_config: Option<Arc<CryptConfig>>,
-    ) -> impl Future<Item=(usize, usize, usize), Error=Error> {
+    ) -> impl Future<Item=(usize, usize, usize, [u8; 32]), Error=Error> {
 
         let repeat = std::sync::Arc::new(AtomicUsize::new(0));
         let repeat2 = repeat.clone();
@@ -880,6 +880,9 @@ impl BackupClient {
 
         let start_time = std::time::Instant::now();
 
+        let index_csum = Arc::new(Mutex::new(Some(openssl::sha::Sha256::new())));
+        let index_csum_2 = index_csum.clone();
+
         stream
             .and_then(move |data| {
 
@@ -897,6 +900,12 @@ impl BackupClient {
 
                 let mut known_chunks = known_chunks.lock().unwrap();
                 let digest = chunk_builder.digest();
+
+                let mut guard = index_csum.lock().unwrap();
+                let csum = guard.as_mut().unwrap();
+                csum.update(&offset.to_le_bytes());
+                csum.update(digest);
+
                 let chunk_is_known = known_chunks.contains(digest);
                 if chunk_is_known {
                     Ok(MergedChunkInfo::Known(vec![(offset, *digest)]))
@@ -962,7 +971,11 @@ impl BackupClient {
                     println!("Average chunk size was {} bytes.", stream_len/repeat);
                     println!("Time per request: {} microseconds.", (start_time.elapsed().as_micros())/(repeat as u128));
                 }
-                Ok((repeat, stream_len, speed))
+
+                let mut guard = index_csum_2.lock().unwrap();
+                let csum = guard.take().unwrap().finish();
+
+                Ok((repeat, stream_len, speed, csum))
             })
     }