private const val TRANSFORMATION = "RSA/ECB/PKCS1Padding"

internal fun rsaEncrypt(data: String, keyPair: KeyPair): String {
    val cipher = Cipher.getInstance(TRANSFORMATION)
    cipher.init(Cipher.ENCRYPT_MODE, keyPair.private)
    val bytes = cipher.doFinal(data.toByteArray(Charsets.UTF_8))
    return Base64.encodeToString(bytes, 0)
}

internal fun rsaDecrypt(data: String, keyPair: KeyPair): String {
    val cipher = Cipher.getInstance(TRANSFORMATION)
    cipher.init(Cipher.DECRYPT_MODE, keyPair.public)
    val bytes = Base64.decode(data, 0)
    val decrypted = cipher.doFinal(bytes)
    return String(decrypted, Charsets.UTF_8)
}