Byte Array To String Conversion Inconsistency

Question

I am testing out AES encryption on android and i need to convert the encrypted text to a string so as to store it in my firebase database. I managed to do so sucessfully. The problem comes when I try to retrieve the string from the database and convert it back to a byte array for decryption. The retreived string is identical to the string sent to the database but when i convert it to a byte array and compare the two values, they are different as seen in the code sample below. I even made sure to use the same Charset but this did not fix the issue.

        val encryptedPair: Pair<ByteArray,ByteArray> = encrypt("text")
        val enc: MutableMap<String, Any> = HashMap()
        enc["ciphertext"] = encryptedPair.second.toString(Charsets.UTF_8).trim()

        fireStoreDatabase.collection("enc").document("test").set(enc)
            .addOnSuccessListener {
                fireStoreDatabase.collection("enc").document("test").get()
                    .addOnSuccessListener { doc->
                        //The below if condition prints out encrytion method: diff
 if(encryptedPair.second.contentEquals(doc.getString("password")!!.toByteArray(Charsets.UTF_8)))
                            Log.e("encryption method: ","same")
                        else
                            Log.e("encryption method: ","diff")
                    }
            }

This difference leads to the decryption process failing. Note that when i try to encrypt and decrypt with the values locally, it works as expected. So i know the problem is with the byte array i get from firebase.

Any suggestions would be appreciated.

Answer 1

As Jon Skeet has suggested, using

val enc: MutableMap<String, Any> = HashMap()
enc["ciphertext"] = Blob.fromBytes(encryptedPair.second)
fireStoreDatabase.collection("enc").document("test").set(enc)

to save the data to firebase and then retrieving it with:

doc.getBlob("ciphertext")!!.toBytes())

worked as expected.