How do I derive a self-authenticating principal from a public key in Motoko?

Developers
1

I have a motoko-based canister that I’d like to construct a self-authenticating principal for. I mean to retrieve the canister’s public key using the ecdsa_public_key function that is present within the canister manager interface. After retrieving the public key, how do I go about manipulating that public key in order to get a self-authenticating principal from it?

2

You hash it and add the 0x02 byte to the hash

May I ask why?

And another question to anyone who can answer: will that principal be the same as the canister principle?

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3

No, the canister principal is essentially like a serial number.

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4

Thank you! some functions within the NNS’s governance canister are required to be called using a self-authenticating principal. So I’ve got to derive one in order to use them.

5

So how are you making the call, if not an inter canister call whereby the canister principal is the caller?

Do you need ecdsa_public_key to call the NNS canister?

I might be missing something

6

I make the call via an HTTP outcall where the body is a request that has been signed by the canister and the sender of the call is the self-authenticating principal that I derive from the ecdsa_public_key .

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7

I see. So a HTTP out to icp-api.io?
Curious to learn what we gain from this compared to inter canister call to nns?