From e0b915a3c34053ff0e08dab0184cfad55b4a4aea Mon Sep 17 00:00:00 2001
From: sbiscigl <sbiscigl@amazon.com>
Date: Thu, 28 May 2026 16:57:11 -0400
Subject: [PATCH] Only calculate full body checksum for checksums that support
 it

---
 .../source/transfer/TransferManager.cpp       | 20 +++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/aws-cpp-sdk-transfer/source/transfer/TransferManager.cpp b/src/aws-cpp-sdk-transfer/source/transfer/TransferManager.cpp
index addee26d984..506b3c40245 100644
--- a/src/aws-cpp-sdk-transfer/source/transfer/TransferManager.cpp
+++ b/src/aws-cpp-sdk-transfer/source/transfer/TransferManager.cpp
@@ -407,18 +407,18 @@ namespace Aws
             bool isRetry = !handle->GetMultiPartId().empty();
             uint64_t sentBytes = 0;
 
-            const auto fullObjectHashCalculator = [](const std::shared_ptr<TransferHandle>& handle, bool isRetry, S3::Model::ChecksumAlgorithm algorithm) -> std::shared_ptr<Aws::Utils::Crypto::Hash> {
+            const auto fullObjectHashCalculator = [](const std::shared_ptr<TransferHandle>& handle, bool isRetry,
+                                                     S3::Model::ChecksumAlgorithm algorithm) -> std::shared_ptr<Aws::Utils::Crypto::Hash> {
                 if (handle->GetChecksum().empty() && !isRetry) {
-                    if (algorithm == S3::Model::ChecksumAlgorithm::CRC32 || algorithm == S3::Model::ChecksumAlgorithm::CRC32C) {
-                        return Aws::MakeShared<Aws::Utils::Crypto::CRC32>("TransferManager");
+                    if (algorithm == S3::Model::ChecksumAlgorithm::CRC64NVME) {
+                      return Aws::MakeShared<Aws::Utils::Crypto::CRC64>("TransferManager");
                     }
-                    if (algorithm == S3::Model::ChecksumAlgorithm::SHA1) {
-                        return Aws::MakeShared<Aws::Utils::Crypto::Sha1>("TransferManager");
+                    if (algorithm == S3::Model::ChecksumAlgorithm::CRC32) {
+                        return Aws::MakeShared<Aws::Utils::Crypto::CRC32>("TransferManager");
                     }
-                    if (algorithm == S3::Model::ChecksumAlgorithm::SHA256) {
-                        return Aws::MakeShared<Aws::Utils::Crypto::Sha256>("TransferManager");
+                    if (algorithm == S3::Model::ChecksumAlgorithm::CRC32C) {
+                        return Aws::MakeShared<Aws::Utils::Crypto::CRC32C>("TransferManager");
                     }
-                    return Aws::MakeShared<Aws::Utils::Crypto::CRC64>("TransferManager");
                 }
                 return nullptr;
             }(handle, isRetry, m_transferConfig.checksumAlgorithm);
@@ -432,6 +432,10 @@ namespace Aws
               createMultipartRequest.SetKey(handle->GetKey());
               createMultipartRequest.SetMetadata(handle->GetMetadata());
 
+              if (fullObjectHashCalculator) {
+                createMultipartRequest.SetChecksumType(Aws::S3::Model::ChecksumType::FULL_OBJECT);
+              }
+
               auto createMultipartResponse = m_transferConfig.s3Client->CreateMultipartUpload(createMultipartRequest);
               if (createMultipartResponse.IsSuccess()) {
                 handle->SetMultipartId(createMultipartResponse.GetResult().GetUploadId());