Debugging...

src/ghash/mod.rs

@@ -9,10 +9,7 @@ pub use verifier::Verifier;
 
 use crate::ole::Ole;
 
-pub fn ghash(blocks: &[Gf2_128], h_prover: Gf2_128, h_verifier: Gf2_128) -> Gf2_128 {
-    let mut prover = Prover::new(blocks.len(), h_prover);
-    let mut verifier = Verifier::new(blocks.len(), h_verifier);
-
+pub fn ghash(blocks: &[Gf2_128], prover: &mut Prover, verifier: &mut Verifier) -> Gf2_128 {
     let mut ole = Ole::default();
 
     prover.preprocess_ole_input(&mut ole);
@@ -71,10 +68,13 @@ mod tests {
         let h2: Gf2_128 = Gf2_128::rand(&mut rng);
         let h = h1 + h2;
 
-        let ghash = ghash(&blocks, h1, h2);
+        let mut prover = Prover::new(blocks.len(), h1);
+        let mut verifier = Verifier::new(blocks.len(), h2);
+
+        let ghash = ghash(&blocks, &mut prover, &mut verifier);
 
         let ghash_expected = {
-            let mut hi = vec![Gf2_128::one(), h];
+            let mut hi = vec![h];
             compute_product_repeated(&mut hi, h, blocks.len());
 
             blocks
@@ -83,7 +83,24 @@ mod tests {
                 .fold(Gf2_128::zero(), |acc, (&b, &h)| acc + (b * h))
         };
 
-        assert_eq!(ghash.to_be_bytes(), ghash_expected.to_be_bytes());
+        assert_eq!(ghash, ghash_expected);
+    }
+
+    #[test]
+    fn test_ghash_invariants() {
+        let mut rng = thread_rng();
+        let blocks: Vec<Gf2_128> = (0..10).map(|_| Gf2_128::rand(&mut rng)).collect();
+
+        let h1: Gf2_128 = Gf2_128::rand(&mut rng);
+        let h2: Gf2_128 = Gf2_128::rand(&mut rng);
+
+        let mut prover = Prover::new(blocks.len(), h1);
+        let mut verifier = Verifier::new(blocks.len(), h2);
+
+        let _ = ghash(&blocks, &mut prover, &mut verifier);
+
+        assert_eq!(prover.h1, prover.hi[1]);
+        assert_eq!(verifier.h2, verifier.hi[1]);
     }
 
     #[test]

src/ghash/prover.rs

@@ -1,16 +1,19 @@
 use super::pascal_tri;
 use crate::ole::{Ole, Role};
-use mpz_share_conversion_core::fields::{compute_product_repeated, gf2_128::Gf2_128, UniformRand};
+use mpz_share_conversion_core::{
+    fields::{compute_product_repeated, gf2_128::Gf2_128, UniformRand},
+    Field,
+};
 use rand::thread_rng;
 
 #[derive(Debug)]
 pub struct Prover {
-    block_num: usize,
-    h1: Gf2_128,
-    r1: Gf2_128,
-    ai: Vec<Gf2_128>,
-    d: Option<Gf2_128>,
-    hi: Vec<Gf2_128>,
+    pub(crate) block_num: usize,
+    pub(crate) h1: Gf2_128,
+    pub(crate) r1: Gf2_128,
+    pub(crate) ai: Vec<Gf2_128>,
+    pub(crate) d: Option<Gf2_128>,
+    pub(crate) hi: Vec<Gf2_128>,
 }
 
 impl Prover {
@@ -48,20 +51,24 @@ impl Prover {
     }
 
     pub fn handshake_a_set_hi(&mut self) {
-        let mut di = vec![Gf2_128::new(1)];
+        let mut di = vec![Gf2_128::one(), self.d.unwrap()];
         compute_product_repeated(&mut di, self.d.unwrap(), self.block_num);
 
         let pascal_tri = pascal_tri::<Gf2_128>(self.block_num);
 
-        for k in 0..self.block_num {
-            for el in pascal_tri[k].iter() {
-                self.hi.push(*el * di[k] * self.ai[self.block_num - k]);
-            }
+        for pascal_row in pascal_tri.iter() {
+            let h_pow_share = pascal_row
+                .iter()
+                .enumerate()
+                .fold(Gf2_128::new(0), |acc, (i, &el)| {
+                    acc + el * di[i] * self.ai[pascal_row.len() - 1 - i]
+                });
+            self.hi.push(h_pow_share);
         }
     }
 
     pub fn handshake_output_ghash(&self, blocks: &[Gf2_128]) -> Gf2_128 {
-        let mut res = Gf2_128::new(0);
+        let mut res = Gf2_128::zero();
 
         for (i, block) in blocks.iter().enumerate() {
             res = res + *block * self.hi[i];

src/ghash/verifier.rs

@@ -1,16 +1,19 @@
 use super::pascal_tri;
 use crate::ole::{Ole, Role};
-use mpz_share_conversion_core::fields::{compute_product_repeated, gf2_128::Gf2_128, UniformRand};
+use mpz_share_conversion_core::{
+    fields::{compute_product_repeated, gf2_128::Gf2_128, UniformRand},
+    Field,
+};
 use rand::thread_rng;
 
 #[derive(Debug)]
 pub struct Verifier {
-    block_num: usize,
-    h2: Gf2_128,
-    r2: Gf2_128,
-    bi: Vec<Gf2_128>,
-    d: Option<Gf2_128>,
-    hi: Vec<Gf2_128>,
+    pub(crate) block_num: usize,
+    pub(crate) h2: Gf2_128,
+    pub(crate) r2: Gf2_128,
+    pub(crate) bi: Vec<Gf2_128>,
+    pub(crate) d: Option<Gf2_128>,
+    pub(crate) hi: Vec<Gf2_128>,
 }
 
 impl Verifier {
@@ -48,15 +51,19 @@ impl Verifier {
     }
 
     pub fn handshake_a_set_hi(&mut self) {
-        let mut di = vec![Gf2_128::new(1)];
+        let mut di = vec![Gf2_128::one(), self.d.unwrap()];
         compute_product_repeated(&mut di, self.d.unwrap(), self.block_num);
 
         let pascal_tri = pascal_tri::<Gf2_128>(self.block_num);
 
-        for k in 0..self.block_num {
-            for el in pascal_tri[k].iter() {
-                self.hi.push(*el * di[k] * self.bi[self.block_num - k]);
-            }
+        for pascal_row in pascal_tri.iter() {
+            let h_pow_share = pascal_row
+                .iter()
+                .enumerate()
+                .fold(Gf2_128::new(0), |acc, (i, &el)| {
+                    acc + el * di[i] * self.bi[pascal_row.len() - 1 - i]
+                });
+            self.hi.push(h_pow_share);
         }
     }