CODEWITHSUNDEEP
socketsgoelliptic-curveecdsa
Daniel Perdana Putra
Daniel Perdana Putra

Reputation: 49

How to convert data type ECDSA private key in Go

I am using the ecdsa.GenerateKey method to generate a private key pair in Go. I would like to send my private key(priva) with socket programming and can read other private key(privb) from other program.

priva, _ := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)

_, err = connection.Write([]byte(priva))
buffer := make([]byte, 1024)
mLen, err := connection.Read(buffer)
if err != nil {
    fmt.Println("Error reading:", err.Error())
}
privb := buffer[:mLen]

There is my code to send data and read data to/from other program, but i can't send my private key(priva) because it can't change the types. How to fixed, or is there a recommended way to send/read the data ?

Upvotes: 3

Views: 2266

Answers (1)

mpx
mpx

Reputation: 1354

The *ecdsa.PrivateKey cannot be directly sent over the network. It must be marshalled into a []byte first.

You can use x509.MarshalECPrivateKey to marshal into DER format, and x509.ParseECPrivateKey to unmarshal.

For example:

package main

import (
    "crypto/ecdsa"
    "crypto/elliptic"
    "crypto/rand"
    "crypto/x509"
    "fmt"
)

func main() {
    priv, _ := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)

    derBuf, _ := x509.MarshalECPrivateKey(priv)

    // Transfer []byte to new location.

    privCopy, _ := x509.ParseECPrivateKey(derBuf)

    fmt.Println(priv.Equal(privCopy))
    /// Output: true
}

Note: this example doesn't provide any additional security around the private key. You may want to ensure the transfer/protocol handling is appropriate for your security needs.

Upvotes: 2

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