From 1bb746c888347ac8f226b975c8e811baa6f3cbea Mon Sep 17 00:00:00 2001
From: Didactic Drunk <1479616+didactic-drunk@users.noreply.github.com>
Date: Tue, 23 Mar 2021 15:52:15 -0700
Subject: [PATCH] Add KDF.xchacha20poly1305_ietf

---
 src/sodium/kdf.cr | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/sodium/kdf.cr b/src/sodium/kdf.cr
index c2112f4..9b71e45 100644
--- a/src/sodium/kdf.cr
+++ b/src/sodium/kdf.cr
@@ -91,6 +91,14 @@ module Sodium
       Sign::SecretKey.new seed: subkey
     end
 
+    # Convenience method to create a new CryptoBox::Aead::XChaCha20Poly1305Ietf without handling the key.
+    #
+    # See derive() for further information on context and subkey_id.
+    def derive_aead_xchacha20poly1305_ietf(context, subkey_id) : Cipher::Aead::XChaCha20Poly1305Ietf
+      subkey = derive context, subkey_id, Cipher::Aead::XChaCha20Poly1305Ietf::KEY_SIZE
+      Cipher::Aead::XChaCha20Poly1305Ietf.new subkey
+    end
+
     # Convenience method to create a new SecretBox without handling the key.
     #
     # See derive() for further information on context and subkey_id.