preMasterSecret := make([]byte, 48)
	preMasterSecret[0] = byte(clientHello.vers >> 8)
	preMasterSecret[1] = byte(clientHello.vers)
	_, err := io.ReadFull(config.rand(), preMasterSecret[2:])
	if err != nil {
		return nil, nil, err
	}

	rsaKey, ok := cert.PublicKey.(*rsa.PublicKey)
	if !ok {

		}
	}
}

type testKeysFromTest struct {
	version                                        uint16
	suite                                          *cipherSuite
	preMasterSecret                                string
	clientRandom, serverRandom                     string
	masterSecret                                   string
	clientMAC, serverMAC                           string

func masterFromPreMasterSecret(version uint16, suite *cipherSuite, preMasterSecret, clientRandom, serverRandom []byte) []byte {
	seed := make([]byte, 0, len(clientRandom)+len(serverRandom))
	seed = append(seed, clientRandom...)
	seed = append(seed, serverRandom...)

	masterSecret := make([]byte, masterSecretLength)
	prfForVersion(version, suite)(masterSecret, preMasterSecret, masterSecretLabel, seed)
	return masterSecret
}

		return unexpectedMessageError(ckx, msg)
	}

	preMasterSecret, err := keyAgreement.processClientKeyExchange(c.config, hs.cert, ckx, c.vers)
	if err != nil {
		c.sendAlert(alertHandshakeFailure)
		return err
	}
	if hs.hello.extendedMasterSecret {
		c.extMasterSecret = true
		hs.masterSecret = extMasterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret,
			hs.finishedHash.Sum())
	} else {

		}
	}

	if hs.serverHello.extendedMasterSecret {
		c.extMasterSecret = true
		hs.masterSecret = extMasterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret,
			hs.finishedHash.Sum())
	} else {
		hs.masterSecret = masterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret,
			hs.hello.random, hs.serverHello.random)
	}
	if err := c.config.writeKeyLog(keyLogLabelTLS12, hs.hello.random, hs.masterSecret); err != nil {