# OfficeEncrypt

Encrypt Office Open XML documents (.xlsx, .docx, .pptx) with a password using ECMA-376 Agile Encryption (AES-256-CBC, SHA-512).

## Installation

Add `office_encrypt` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:office_encrypt, "~> 0.1.0"}
  ]
end
```

## Usage

```elixir
{:ok, data} = File.read("document.xlsx")
encrypted = OfficeEncrypt.encrypt(data, "password123")
File.write!("encrypted.xlsx", encrypted)
```

The encrypted file can be opened with Microsoft Office, LibreOffice, and other compatible applications using the provided password.

## Options

`OfficeEncrypt.encrypt/3` accepts an optional third argument with options:

- `:spin_count` (integer, default: 100,000) - Controls the number of iterations for key derivation. Higher values increase security but take longer to encrypt/decrypt.

```elixir
OfficeEncrypt.encrypt(data, "password123", spin_count: 1_000_000)
```

## Notes

This library provides encryption only. Decryption is not currently supported.

The resulting files are OLE2 compound documents compatible with Microsoft Office and LibreOffice.

## License

MIT