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dogsheep / dogsheep-photos

Upload your photos to S3 and import metadata about them into a SQLite database
Apache License 2.0
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Should I have used MD5 instead of SHA256? #8

Closed simonw closed 4 years ago

simonw commented 4 years ago

https://docs.aws.amazon.com/AmazonS3/latest/API/RESTCommonResponseHeaders.html

Objects created by the PUT Object, POST Object, or Copy operation, or through the AWS Management Console, and are encrypted by SSE-S3 or plaintext, have ETags that are an MD5 digest of their object data.

simonw commented 4 years ago

I don't think it matters one way or the other - I'm storing the sha256 in the filename, so the fact that I could read the MD5 back from the list bucket operation doesn't give me any benefits.

simonw commented 4 years ago

Also MD5 isn't guaranteed for the ETag:

If an object is created by either the Multipart Upload or Part Copy operation, the ETag is not an MD5 digest, regardless of the method of encryption.