From 5e4c31160d73085d12e07be1a95a787fea9206d1 Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Wed, 30 Sep 2020 15:46:56 +0100
Subject: [PATCH] transmute aes key

---
 Cargo.toml |  2 +-
 src/aes.rs | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index 7ca47a6..23506fe 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "cryptohelpers"
-version = "1.4.0"
+version = "1.4.1"
 license= "MIT"
 description = "Collection of helpers and simplifying functions for cryptography things"
 authors = ["Avril <flanchan@cumallover.me>"]
diff --git a/src/aes.rs b/src/aes.rs
index d046ca4..97a8f9d 100644
--- a/src/aes.rs
+++ b/src/aes.rs
@@ -31,6 +31,7 @@ const BLOCKSIZE: usize = 16;
 /// A key and IV for the AES algorithm
 #[derive(Debug, PartialEq, Eq, Clone, Hash, Default)]
 #[cfg_attr(feature="serialise", derive(Serialize,Deserialize))]
+#[repr(align(1))]
 pub struct AesKey {
     key: [u8; KEYSIZE],
     iv: [u8; IVSIZE],
@@ -63,6 +64,30 @@ impl AesKey
 	Self{key,iv}
     }
 
+    /// Consume into the key and IV parts
+    pub const fn into_parts(self) -> ([u8; KEYSIZE], [u8; IVSIZE])
+    {
+        (self.key, self.iv)
+    }
+
+    /// Consume this instance into the full byte buffer
+    pub fn into_bytes(self) -> [u8; KEYSIZE+IVSIZE]
+    {
+        unsafe { std::mem::transmute(self) }
+    }
+
+    /// Consume a full byte buffer into an AES key
+    pub fn from_bytes(from: [u8; KEYSIZE+IVSIZE]) -> Self
+    {	
+        unsafe { std::mem::transmute(from) }
+    }
+
+    /// Create a zero inisialised key
+    #[inline] pub const fn empty() -> Self
+    {
+	Self { iv: [0; IVSIZE], key: [0; KEYSIZE]}
+    }
+
     /// Create a new instance from slices
     pub fn from_slice(key: impl AsRef<[u8]>, iv: impl AsRef<[u8]>) -> Result<Self,Error>
     {
@@ -232,3 +257,26 @@ where F: io::Read + ?Sized,
 }
 
 pub use crate::error::aes::Error;
+
+#[cfg(test)]
+mod tests
+{
+    #[test]
+    fn transmute_safe()
+    {
+	use std::mem::{size_of, align_of};
+
+	assert_eq!(size_of::<super::AesKey>(), size_of::<[u8; super::KEYSIZE + super::IVSIZE]>());
+	assert_eq!(align_of::<super::AesKey>(), align_of::<[u8; super::KEYSIZE + super::IVSIZE]>());
+	let key = super::AesKey::generate().unwrap();
+
+	let bytes = Vec::from(key.as_ref());
+	let tbytes = key.clone().into_bytes();
+
+	let nkey = super::AesKey::from_bytes(tbytes);
+
+	assert_eq!(nkey, key);
+	assert_eq!(&bytes[..], &tbytes[..]);
+	assert_eq!(key.as_ref(), &tbytes[..]);
+    }
+}