Merge pull request #6 from robinhundt/new-kos-consistency-check

New kos consistency check

This implements the new consistency check from Sec. 4 of the updated KOS paper. The implementation is based on this commit in libOTe. However, because we have a configurable batch size, the iteration through the matrices T and V is done differently. Instead of iterating the columns, we iterate the rows. This is a more cache efficient iteration.

Author: robinhundt

.gitignore

@@ -1,5 +1,5 @@
 target
-profile.json
+profile.json*
 perf.data*
 
 .flyio

Cargo.lock

@@ -31,6 +31,7 @@ rand_core_0_6.workspace = true
 rayon = { workspace = true, optional = true }
 serde = { workspace = true, features = ["derive"] }
 subtle.workspace = true
+thiserror.workspace = true
 tokio = { workspace = true, features = ["sync"], optional = true }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true, optional = true }

cryprot-core/Cargo.toml

@@ -11,6 +11,7 @@ use bytemuck::{Pod, Zeroable};
 use rand::{Rng, distr::StandardUniform, prelude::Distribution};
 use serde::{Deserialize, Serialize};
 use subtle::{Choice, ConditionallySelectable, ConstantTimeEq};
+use thiserror::Error;
 use wide::u8x16;
 
 use crate::random_oracle::{self, RandomOracle};
@@ -336,6 +337,20 @@ impl From<&u128> for Block {
     }
 }
 
+#[derive(Debug, Error)]
+#[error("slice must have length of 16")]
+pub struct WrongLength;
+
+impl TryFrom<&[u8]> for Block {
+    type Error = WrongLength;
+
+    #[inline]
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        let arr = value.try_into().map_err(|_| WrongLength)?;
+        Ok(Self::new(arr))
+    }
+}
+
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 mod from_arch_impls {
     #[cfg(target_arch = "x86")]
@@ -472,4 +487,13 @@ mod tests {
             assert_eq!(false, rest);
         }
     }
+
+    #[test]
+    fn test_from_choices() {
+        let mut choices = vec![Choice::from(0); 128];
+        choices[2] = Choice::from(1);
+        choices[16] = Choice::from(1);
+        let blk = Block::from_choices(&choices);
+        assert_eq!(Block::from(1_u128 << 2 | 1_u128 << 16), blk);
+    }
 }