![Why Are My Files Missing a SHA-1?]({"bg": "//theme.zdassets.com/theme_assets/34506/e106cc8a79a6a41c781c71d999cffaa33b481de7.jpg"})
![Why Are My Files Missing a SHA-1?]({"bg": "//theme.zdassets.com/theme_assets/34506/d38d9cc5a4fcb160800cb7a8f0e0cb60aaa36d2e.jpg"})
When large files are uploaded to the B2 servers they are broken up into smaller parts (using the b2 upload_part call), each part of the file is assigned a SHA-1 checksum. The entire large file itself is not assigned a SHA-1 automatically. This is why you are not seeing SHA-1's for certain files.
If you do know the SHA-1 for the entire large file being uploaded, we do recommend specifying the SHA1 in the fileInfo during the call to b2_start_large_file call.
Inside the fileInfo header for the b2_start_large_file call, specify one of the keys as large_file_sha1 and for the value use a 40 byte hex string representing the SHA1.
Articles in this section
- Object Lock FAQs
- Delivering Backblaze B2 Content Through Cloudflare CDN
- Bunny Integration Quick Start Guide
- Guide for using Fastly Compute @ Edge with Backblaze B2
- SSE Command Line and API Examples
- Does the B2 S3 Compatible API support Pre-Signed URLs?
- How to use Fastly CDN with B2
- Using the AWS SDK for Java (v2) with B2
- How to use the AWS SDK for Python with B2.
- Using the AWS SDK for PHP with Backblaze B2 Cloud Storage