gmessages/libgm/payload/registerPhoneRelay.go

package payload

import (
	"go.mau.fi/mautrix-gmessages/libgm/binary"
	"go.mau.fi/mautrix-gmessages/libgm/crypto"
	"go.mau.fi/mautrix-gmessages/libgm/util"
)

func RegisterPhoneRelay(jwk *crypto.JWK) ([]byte, *binary.AuthenticationContainer, error) {
	id := util.RandomUUIDv4()

	encryptedKeys, encryptErr := uncompressKey(jwk)
	if encryptErr != nil {
		return nil, nil, encryptErr
	}

	payloadData := &binary.AuthenticationContainer{
		AuthMessage: &binary.AuthenticationMessage{
			RequestID:     id,
			Network:       Network,
			ConfigVersion: ConfigMessage,
		},
		BrowserDetails: BrowserDetailsMessage,
		Data: &binary.AuthenticationContainer_KeyData{
			KeyData: &binary.KeyData{
				EcdsaKeys: &binary.ECDSAKeys{
					Field1:        2,
					EncryptedKeys: encryptedKeys,
				},
			},
		},
	}
	encoded, err4 := binary.EncodeProtoMessage(payloadData)
	if err4 != nil {
		return nil, payloadData, err4
	}
	return encoded, payloadData, nil
}

func uncompressKey(jwk *crypto.JWK) ([]byte, error) {
	decodedPrivateKey, err2 := jwk.PrivKeyB64Bytes()
	if err2 != nil {
		return nil, err2
	}
	jwk.PrivateBytes = decodedPrivateKey
	uncompressedPublicKey, err3 := jwk.UncompressPubKey()
	if err3 != nil {
		return nil, err3
	}
	var emptyByteArray []byte
	crypto.EncodeValues(&emptyByteArray, crypto.SequenceOne)
	crypto.EncodeValues(&emptyByteArray, crypto.SequenceTwo)

	var copiedByteArray []byte
	copiedByteArray = crypto.AppendByteSequence(copiedByteArray, emptyByteArray, uncompressedPublicKey)
	for _, value := range uncompressedPublicKey {
		copiedByteArray = crypto.HelperAppendBytes(copiedByteArray, value)
	}

	var encryptedKeys []byte
	encryptedKeys = crypto.AppendBytes(encryptedKeys, copiedByteArray[0:])
	return encryptedKeys, nil
}