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How to detect multibase of a CID #15

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SimonLab opened this issue Jan 21, 2019 · 1 comment

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SimonLab commented Jan 21, 2019

Given a CID the first step when decoding the CID is to determine which multibase is used
see https://github.com/multiformats/multibase

The CID(v1) encode this information on the first byte (ie the first 8 bits), see https://github.com/multiformats/cid#decoding-algorithm where:

So the first step is to extract the first byte and to get a representation in hexadecimal. Then we can match with the multibase table to determine which encoding is used (the 0x is an indication to tell us that the text is in base16 which is hexadecimal)

Check the implementations of multibase to know how the first byte is extracted
see https://github.com/multiformats/js-multibase

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SimonLab commented Jan 21, 2019

Knowing the encoding is in fact simple.

Get the first byte/letter
match this first letter with the multibase table with the code column
check the encoding column

see

SimonLab added a commit that referenced this issue


          decode cid v0, #13 #15

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