blockData
The data to write to the block.
The block data is not signed as part of the Signature Version 4 signing process. As a result, you must generate and provide a Base64-encoded SHA256 checksum for the block data using the x-amz-Checksum header. Also, you must specify the checksum algorithm using the x-amz-Checksum-Algorithm header. The checksum that you provide is part of the Signature Version 4 signing process. It is validated against a checksum generated by Amazon EBS to ensure the validity and authenticity of the data. If the checksums do not correspond, the request fails. For more information, see Using checksums with the EBS direct APIs in the Amazon Elastic Compute Cloud User Guide.