encryption_test.go

package easyecc

import (
	"bytes"
	"testing"

	"github.com/ethereum/go-ethereum/crypto"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestEncryption(t *testing.T) {
	require := require.New(t)

	alicePrivateKey, err := GeneratePrivateKey(SECP256K1)
	require.NoError(err)

	bobPrivateKey, err := GeneratePrivateKey(SECP256K1)
	require.NoError(err)

	key1x, key1y := crypto.S256().ScalarMult(alicePrivateKey.PublicKey().X(), alicePrivateKey.PublicKey().Y(),
		bobPrivateKey.Secret().Bytes())

	key2x, key2y := crypto.S256().ScalarMult(bobPrivateKey.PublicKey().X(), bobPrivateKey.PublicKey().Y(),
		alicePrivateKey.Secret().Bytes())

	require.Equal(key1x, key2x)
	require.Equal(key1y, key2y)
}

func TestEncryptDecrypt(t *testing.T) {
	assert := assert.New(t)

	alicePrivateKey, err := GeneratePrivateKey(P256)
	assert.NoError(err)

	bobPrivateKey, err := GeneratePrivateKey(P256)
	assert.NoError(err)

	message := "All that we are is the result of what we have thought"
	ciphertext, err := alicePrivateKey.EncryptECDH([]byte(message), bobPrivateKey.PublicKey())
	assert.NoError(err)

	plaintext, err := bobPrivateKey.DecryptECDH(ciphertext, alicePrivateKey.PublicKey())
	assert.NoError(err)

	assert.True(bytes.Equal([]byte(message), plaintext))

	// Test error on different curves.
	spongeBobPrivateKey, err := GeneratePrivateKey(P521)
	assert.NoError(err)
	_, err = alicePrivateKey.EncryptECDH([]byte(message), spongeBobPrivateKey.PublicKey())
	assert.Equal(ErrDifferentCurves, err)
}

func TestEncryptDecryptSymmetric(t *testing.T) {
	assert := assert.New(t)

	privateKey, err := GeneratePrivateKey(P521)
	assert.NoError(err)

	message := "super secret message"
	encrypted, err := privateKey.EncryptSymmetric([]byte(message))
	assert.NoError(err)

	assert.True(len(encrypted) > len([]byte(message)))

	decrypted, err := privateKey.DecryptSymmetric(encrypted)
	assert.NoError(err)
	assert.EqualValues(message, string(decrypted))
}