From 84dcbce9f55af140b904869b644e9ddc835511d5 Mon Sep 17 00:00:00 2001
From: vysion <77179954+vysiondev@users.noreply.github.com>
Date: Wed, 30 Mar 2022 12:16:16 -0700
Subject: [PATCH] Add DeriveKey func

---
 encryption/derive_key.go | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/encryption/derive_key.go b/encryption/derive_key.go
index 909a131..741baf7 100644
--- a/encryption/derive_key.go
+++ b/encryption/derive_key.go
@@ -1 +1,36 @@
 package encryption
+
+import (
+	"crypto/sha512"
+	"golang.org/x/crypto/hkdf"
+	"io"
+)
+
+func DeriveKey(k []byte, nonce []byte) ([32]byte, error) {
+	var key [32]byte
+
+	// TODO: remove experiment
+	//d := sha3.NewShake256()
+	//_, err := d.Write(k)
+	//if err != nil {
+	//	return [64]byte{}, err
+	//}
+	//_, err = d.Write(nonce)
+	//if err != nil {
+	//	return [64]byte{}, err
+	//}
+	//
+	//_, err = d.Read(key[:])
+	//if err != nil {
+	//	return [64]byte{}, err
+	//}
+
+	// SHA2-512 related code
+	kdf := hkdf.New(sha512.New, k, nonce, nil)
+	_, err := io.ReadFull(kdf, key[:])
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	return key, nil
+}