Import ecies keys from ecdsa keys

[udhos]

Hi,

How can I import ecies keys from existing ecdsa keys?

• ecies.PrivateKey from ecdsa.PrivateKey
• ecies.PublicKey from ecdsa.PublicKey

ecdsa: https://golang.org/pkg/crypto/ecdsa/
ecies: https://github.com/ecies/go

Thanks,
Everton

[kigawas]

You have to use the same elliptic curve, which is secp256k1, and import it with hex string or bytes

[udhos]

I see that there are helper functions to import ecies keys from bytes. But how to properly export ecdsa keys to bytes?

[kigawas]

You can check the documentation of ecdsa.

It's just a big int, you can convert it to bytes.

[savely-krasovsky]

Well, sure I can add the helper function that accepts ecdsa.PrivateKey; the problem is that this private key MUST BE secp256k1 curve.

I hope library user SHOULD understand how it works and be able to write such a function himself.

[udhos]

In my specific case, the ecdsa key is P256:

P256 returns a Curve which implements NIST P-256 (FIPS 186-3, section D.2.3), also known as secp256r1 or prime256v1. The CurveParams.Name of this Curve is "P-256".

Can I just export its big Int D data as []byte and feed It into NewPrivateKeyFromBytes() ?

[savely-krasovsky]

@udhos well, currently this library set does NOT support secp256r1 or anything else except secp256k1.

We already discuss it here: ecies/py#81