如何在GoLang中分离编组的ecdsa公钥和私钥

Question

So far, I have:

key, err := ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
if err != nil {
    os.Exit(-1)
}
marshalled, err := x509.MarshalECPrivateKey(key) // marshalls data to byte stream
if err != nil {
    os.Exit(-1)
}

Basically, what I am having trouble with has to do with the fact that when a key pair is generated, it is stored in an *ecdsa.PrivateKey, in which the public key is stored in the *ecdsa.PrivateKey.PublicKey, and when I marshall the key pair data (stored in the *ecdsa.PrivateKey) using x509.MarshalECPrivateKey(key), a single byte slice is returned. I am therefore having trouble determining which are the public and private keys in the byte slice itself.

Answer 1

The private key is a superset of the public key. It always contains the public key. Usually a public key is stored as part of a certificate.

If you really want to get the public key by itself, you can grab the X and Y big integers from the ecdsa public key struct and store the binary representation of them.

You might benefit from a bit of retrospect on your design here. There aren't too many situations where you need to communicate a public key alone.