utility_cryptography.go

// ABOUTME: Cryptographic utilities for RSA keypair generation and
// ABOUTME: canonical public key encoding used to derive addresses.
package quark

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/sha256"
	"crypto/x509"
	"encoding/hex"
	"errors"
)

func generateKeypair() (*rsa.PrivateKey, *rsa.PublicKey, error) {
	privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		return nil, nil, err
	}
	return privateKey, &privateKey.PublicKey, nil
}

func marshalPublicKey(pub *rsa.PublicKey) ([]byte, error) {
	return x509.MarshalPKIXPublicKey(pub)
}

func unmarshalPublicKey(b []byte) (*rsa.PublicKey, error) {
	k, err := x509.ParsePKIXPublicKey(b)
	if err != nil {
		return nil, err
	}
	pub, ok := k.(*rsa.PublicKey)
	if !ok {
		return nil, errors.New("not an RSA public key")
	}
	return pub, nil
}

func addressFromPublicKey(pub *rsa.PublicKey) (string, error) {
	b, err := marshalPublicKey(pub)
	if err != nil {
		return "", err
	}
	h := sha256.Sum256(b)
	return hex.EncodeToString(h[:]), nil
}