# 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
```