# `Fields.AES`

Encrypt values with AES in Galois/Counter Mode (GCM)
https://en.wikipedia.org/wiki/Galois/Counter_Mode
using a random Initialisation Vector for each encryption,
this makes "bruteforce" decryption much more difficult.
See `encrypt/1` and `decrypt/1` for more details.

# `decrypt`

```elixir
@spec decrypt(any()) :: String.t()
```

Decrypt a binary using GCM.
## Parameters
- `ciphertext`: a binary to decrypt, assuming that the first 16 bytes of the
  binary are the IV to use for decryption.
- `key_id`: the index of the AES encryption key used to encrypt the ciphertext
## Example
iex> Fields.AES.encrypt("test") |> Fields.AES.decrypt()
"test"

# `encrypt`

```elixir
@spec encrypt(any()) :: String.t()
```

Encrypt Using AES GCM.
Uses a random IV for each call, and prepends the IV and Tag to the
ciphertext.  This means that `encrypt/1` will never return the same ciphertext
for the same value. This makes "cracking" (bruteforce decryption) much harder!
## Parameters
- `plaintext`: Accepts any data type as all values are converted to a String
  using `to_string` before encryption.
- `key_id`: the index of the AES encryption key used to encrypt the ciphertext
## Examples
iex> Fields.AES.encrypt("tea") != Fields.AES.encrypt("tea")
true
iex> ciphertext = Fields.AES.encrypt(123)
iex> is_binary(ciphertext)
true

---

*Consult [api-reference.md](api-reference.md) for complete listing*