Add byte serialization

test/private-box.test.ts

@@ -52,7 +52,7 @@ test('Encrypt with different context', async () => {
   expect(unboxed).toBeNull()
 })
 
-test('serialization', async () => {
+test('String serialization', async () => {
   const box = await PrivateBox.encrypt(message, k1.publicKey)
   expect(box).not.toBeNull()
 
@@ -66,3 +66,17 @@ test('serialization', async () => {
   expect(unboxed).not.toBeNull()
   expect(unboxed).toEqual(message)
 })
+test('Byte serialization', async () => {
+  const box = await PrivateBox.encrypt(message, k1.publicKey)
+  expect(box).not.toBeNull()
+
+  const ser = await box!.toBytes()
+  const de = await PrivateBox.fromBytes(ser)
+
+  expect(de).not.toBeNull()
+  expect(de).toEqual(box)
+
+  const unboxed = await de!.decrypt(k1.privateKey)
+  expect(unboxed).not.toBeNull()
+  expect(unboxed).toEqual(message)
+})