Hey guys, I try to find information on how to calculate the CIDv0 or CIDv1 from a known SHA256 sum, I couldn’t find info on that, other that SHA256 is used in the CID. I want to be able to receive a file from IPFS without knowing the CIDv0/1 but only the SHA256 sum. Best regards

I don’t think this is possible. For any given file, it’s possible to construct multiple valid CIDs with different properties.

So there’s no way to calculate the CID from the SHA256 hash from a file? Even if I know the file was just added with the default options with ‘ipfs add file.bin’?

[image] RubenKelevra: So there’s no way to calculate the CID from the SHA256 hash from a file? Not that I’m aware of. At least, not unless you want to keep a table of hashes and known CIDs. Someone else might know of a more recent change that would make this possible. [image] RubenKelevra…

I’m thinking about creating a cache program for files which reads a file format which contains an URL and a SHA256 sum. So if someone else used the program before I don’t have to load the file from the URL but can request it from IPFS. Since I cannot change the format itself I have to either attac…

I think I’m missing something. Why can’t your program store a URL and CID? I’m missing why the SHA256 is required instead of something that IPFS can natively use. As a tangent, this sounds related to the experimental urlstore feature. As part of it, you can pass in a URL and get a CID for the file.…

I think I’m missing something. Why can’t your program store a URL and CID? I’m missing why the SHA256 is required instead of something that IPFS can natively use. I want to work with publicly available files which just contain the URL and the SHA256 sum. Sure, I can download a file, calculate th…

[image] RubenKelevra: just contain the URL and the SHA256 sum. Where is the SHA256 hash? Encoded into the URL? Is this just for a specific site or you’re trying to do something for URL caching in general? [image] RubenKelevra: But: How do the next client avoid to download the file again …

I think I found a solution: I’ll just create a folder where all files are stored, and the files are just named with the SHA256 hash. This way I can access the files via an ipns name. This is obviously a cluster solution, which needs multiple or one computer, downloading the file and storing it in…

Hello, I try to find information on how to calculate the CIDv0 or CIDv1 from a known SHA256 sum A CID is just a SHA-256 hash (or any other hash type), wrapped with some prefixes , so you can perfectly do this, usually programmatically… GitHub - whyrusleeping/elcid: A cid encoder/decoder tool is a…

Hey @hector , wouldn’t it make sense to calculate the SHA256 hash of the whole as metadata which can be queried like a CID? I’m sure there are many usecases where you know a SHA256 sum of a file and just want to receive it over IPFS - Like reading a sha256sums.txt and adding the files all to a fold…

Receive a file with an known SHA256 sum from IPFS

Help

milahu January 11, 2023, 12:02pm 14

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Receive a file with an known SHA256 sum from IPFS

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