---
title: "Use Data Integrity Checksums"
description: "Verify SOS uploads/downloads with data integrity checksums.  Set CRC32, CRC32C, CRC64NVME on upload and fetch checksums on head-object."
url: https://community.exoscale.com/product/storage/object-storage/how-to/checksum/
product: "Object Storage"
section: product
last_updated: 2026-05-27
---
> For AI agents: the documentation index is at https://community.exoscale.com/llms.txt. Every page is available as markdown at `<page URL>index.md` or with `Accept: text/markdown`.

# Use Data Integrity Checksums

SOS supports data integrity verification using checksums. When uploading objects, you can specify a checksum algorithm and SOS will verify the data was transmitted correctly.

## Supported Algorithms

- CRC32
- CRC32C
- CRC64NVME

## Uploading with Checksum

```bash
aws --endpoint https://sos-ch-gva-2.exo.io/ s3api put-object \
  --bucket my-bucket \
  --key my-object.txt \
  --body my-file.txt \
  --checksum-algorithm CRC32
```

## Retrieving Checksum

Use `--checksum-mode ENABLED` to retrieve an object's checksum:

```bash
aws --endpoint https://sos-ch-gva-2.exo.io/ s3api head-object \
  --bucket my-bucket \
  --key my-object.txt \
  --checksum-mode ENABLED
```