From c8b1a2f0153c008a60f1f4a39f2dfa27adc161a3 Mon Sep 17 00:00:00 2001
From: Jack Wampler <jmwample@users.noreply.github.com>
Date: Thu, 5 Sep 2024 20:05:28 -0600
Subject: [PATCH] Add various hybrid array sizes necessary for Kemeleon (#84)
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I am working on implementing an obfuscated encoding for ML-KEM
encapsulation keys and ciphertexts and there are several non-standard
array sizes that will make inter-operating between the custom library
and `ml-kem` significantly easier. These would also be useful if the
kemeleon encoding strategy is eventually added as a feature inside the
`ml-kem` crate itself.

The encoding and decoding algorithms are described in section 2.4 of
[_Obfuscated Key Exchange_](https://eprint.iacr.org/2024/1086.pdf) by
Günther, Stebila, and Veitch. The output byte array sizes are described
in `Table 2` on page 8.

Co-authored-by: jmwample <8297368+jmwample@users.noreply.github.com>
---
 src/sizes.rs | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/src/sizes.rs b/src/sizes.rs
index 28888eb..69d79ce 100644
--- a/src/sizes.rs
+++ b/src/sizes.rs
@@ -818,6 +818,17 @@ mod extra_sizes {
     pub type U35664 = uint!(0 0 0 0 1 0 1 0 1 1 0 1 0 0 0 1);
     pub type U49856 = uint!(0 0 0 0 0 0 1 1 0 1 0 0 0 0 1 1);
 
+    // Kemeleon ML-KEM Encoding sizes
+    pub type U749 = uint!(0 0 1 0 1 1 1 0 1 1 0 1);
+    pub type U781 = uint!(0 0 1 1 0 0 0 0 1 1 0 1);
+    pub type U877 = uint!(0 0 1 1 0 1 1 0 1 1 0 1);
+    pub type U1124 = uint!(0 1 0 0 0 1 1 0 0 1 0 0);
+    pub type U1156 = uint!(0 1 0 0 1 0 0 0 0 1 0 0);
+    pub type U1252 = uint!(0 1 0 0 1 1 1 0 0 1 0 0);
+    pub type U1498 = uint!(0 1 0 1 1 1 0 1 1 0 1 0);
+    pub type U1530 = uint!(0 1 0 1 1 1 1 1 1 0 1 0);
+    pub type U1626 = uint!(0 1 1 0 0 1 0 1 1 0 1 0);
+
     impl_array_sizes! {
         1040 => U1040,
         1056 => U1056,
@@ -1027,4 +1038,17 @@ mod extra_sizes {
         35664 => U35664,
         49856 => U49856,
     }
+
+    // Kemeleon ML-KEM Encoding sizes
+    impl_array_sizes! {
+        749 => U749,
+        781 => U781,
+        877 => U877,
+        1124 => U1124,
+        1156 => U1156,
+        1252 => U1252,
+        1498 => U1498,
+        1530 => U1530,
+        1626 => U1626,
+    }
 }