Uint traits

Cargo.toml

@@ -10,7 +10,7 @@ categories = ["cryptography", "no-std"]
 rust-version = "1.73"
 
 [dependencies]
-crypto-bigint = { version = "0.6.0-pre.5", default-features = false, features = ["rand_core"] }
+crypto-bigint = { version = "0.6.0-pre.5", default-features = false, features = ["alloc", "rand_core"] }
 rand_core = { version = "0.6.4", default-features = false }
 openssl = { version = "0.10.39", optional = true, features = ["vendored"] }
 rug = { version = "1.18", default-features = false, features = ["integer"], optional = true }

benches/bench.rs

@@ -22,8 +22,8 @@ fn make_rng() -> ChaCha8Rng {
     ChaCha8Rng::from_seed(*b"01234567890123456789012345678901")
 }
 
-fn make_sieve<const L: usize>(rng: &mut impl CryptoRngCore) -> Sieve<L> {
-    let start = random_odd_uint::<L>(rng, Uint::<L>::BITS);
+fn make_sieve<const L: usize>(rng: &mut impl CryptoRngCore) -> Sieve<Uint<L>> {
+    let start = random_odd_uint::<Uint<L>>(rng, Uint::<L>::BITS, Uint::<L>::BITS);
     Sieve::new(&start, Uint::<L>::BITS, false)
 }
 
@@ -36,13 +36,13 @@ fn bench_sieve(c: &mut Criterion) {
     let mut group = c.benchmark_group("Sieve");
 
     group.bench_function("(U128) random start", |b| {
-        b.iter(|| random_odd_uint::<{ nlimbs!(128) }>(&mut OsRng, 128))
+        b.iter(|| random_odd_uint::<Uint<{ nlimbs!(128) }>>(&mut OsRng, 128, 128))
     });
 
     group.bench_function("(U128) creation", |b| {
         b.iter_batched(
-            || random_odd_uint::<{ nlimbs!(128) }>(&mut OsRng, 128),
-            |start| Sieve::new(&start, 128, false),
+            || random_odd_uint::<Uint<{ nlimbs!(128) }>>(&mut OsRng, 128, 128),
+            |start| Sieve::new(start.as_ref(), 128, false),
             BatchSize::SmallInput,
         )
     });
@@ -57,13 +57,13 @@ fn bench_sieve(c: &mut Criterion) {
     });
 
     group.bench_function("(U1024) random start", |b| {
-        b.iter(|| random_odd_uint::<{ nlimbs!(1024) }>(&mut OsRng, 1024))
+        b.iter(|| random_odd_uint::<Uint<{ nlimbs!(1024) }>>(&mut OsRng, 1024, 1024))
     });
 
     group.bench_function("(U1024) creation", |b| {
         b.iter_batched(
-            || random_odd_uint::<{ nlimbs!(1024) }>(&mut OsRng, 1024),
-            |start| Sieve::new(&start, 1024, false),
+            || random_odd_uint::<Uint<{ nlimbs!(1024) }>>(&mut OsRng, 1024, 1024),
+            |start| Sieve::new(start.as_ref(), 1024, false),
             BatchSize::SmallInput,
         )
     });
@@ -84,7 +84,7 @@ fn bench_miller_rabin(c: &mut Criterion) {
 
     group.bench_function("(U128) creation", |b| {
         b.iter_batched(
-            || random_odd_uint::<{ nlimbs!(128) }>(&mut OsRng, 128),
+            || random_odd_uint::<Uint<{ nlimbs!(128) }>>(&mut OsRng, 128, 128),
             MillerRabin::new,
             BatchSize::SmallInput,
         )
@@ -100,7 +100,7 @@ fn bench_miller_rabin(c: &mut Criterion) {
 
     group.bench_function("(U1024) creation", |b| {
         b.iter_batched(
-            || random_odd_uint::<{ nlimbs!(1024) }>(&mut OsRng, 1024),
+            || random_odd_uint::<Uint<{ nlimbs!(1024) }>>(&mut OsRng, 1024, 1024),
             MillerRabin::new,
             BatchSize::SmallInput,
         )
@@ -193,39 +193,39 @@ fn bench_presets(c: &mut Criterion) {
 
     group.bench_function("(U128) Prime test", |b| {
         b.iter_batched(
-            || random_odd_uint::<{ nlimbs!(128) }>(&mut OsRng, 128),
-            |num| is_prime_with_rng(&mut OsRng, &num),
+            || random_odd_uint::<Uint<{ nlimbs!(128) }>>(&mut OsRng, 128, 128),
+            |num| is_prime_with_rng(&mut OsRng, num.as_ref()),
             BatchSize::SmallInput,
         )
     });
 
     group.bench_function("(U128) Safe prime test", |b| {
         b.iter_batched(
-            || random_odd_uint::<{ nlimbs!(128) }>(&mut OsRng, 128),
-            |num| is_safe_prime_with_rng(&mut OsRng, &num),
+            || random_odd_uint::<Uint<{ nlimbs!(128) }>>(&mut OsRng, 128, 128),
+            |num| is_safe_prime_with_rng(&mut OsRng, num.as_ref()),
             BatchSize::SmallInput,
         )
     });
 
     let mut rng = make_rng();
     group.bench_function("(U128) Random prime", |b| {
-        b.iter(|| generate_prime_with_rng::<{ nlimbs!(128) }>(&mut rng, None))
+        b.iter(|| generate_prime_with_rng::<Uint<{ nlimbs!(128) }>>(&mut rng, 128, 128))
     });
 
     let mut rng = make_rng();
     group.bench_function("(U1024) Random prime", |b| {
-        b.iter(|| generate_prime_with_rng::<{ nlimbs!(1024) }>(&mut rng, None))
+        b.iter(|| generate_prime_with_rng::<Uint<{ nlimbs!(1024) }>>(&mut rng, 1024, 1024))
     });
 
     let mut rng = make_rng();
     group.bench_function("(U128) Random safe prime", |b| {
-        b.iter(|| generate_safe_prime_with_rng::<{ nlimbs!(128) }>(&mut rng, None))
+        b.iter(|| generate_safe_prime_with_rng::<Uint<{ nlimbs!(128) }>>(&mut rng, 128, 128))
     });
 
     group.sample_size(20);
     let mut rng = make_rng();
     group.bench_function("(U1024) Random safe prime", |b| {
-        b.iter(|| generate_safe_prime_with_rng::<{ nlimbs!(1024) }>(&mut rng, None))
+        b.iter(|| generate_safe_prime_with_rng::<Uint<{ nlimbs!(1024) }>>(&mut rng, 1024, 1024))
     });
 
     group.finish();
@@ -235,19 +235,19 @@ fn bench_presets(c: &mut Criterion) {
 
     let mut rng = make_rng();
     group.bench_function("(U128) Random safe prime", |b| {
-        b.iter(|| generate_safe_prime_with_rng::<{ nlimbs!(128) }>(&mut rng, None))
+        b.iter(|| generate_safe_prime_with_rng::<Uint<{ nlimbs!(128) }>>(&mut rng, 128, 128))
     });
 
     // The performance should scale with the prime size, not with the Uint size.
     // So we should strive for this test's result to be as close as possible
     // to that of the previous one and as far away as possible from the next one.
     group.bench_function("(U256) Random 128 bit safe prime", |b| {
-        b.iter(|| generate_safe_prime_with_rng::<{ nlimbs!(256) }>(&mut rng, Some(128)))
+        b.iter(|| generate_safe_prime_with_rng::<Uint<{ nlimbs!(256) }>>(&mut rng, 128, 256))
     });
 
     // The upper bound for the previous test.
     group.bench_function("(U256) Random 256 bit safe prime", |b| {
-        b.iter(|| generate_safe_prime_with_rng::<{ nlimbs!(256) }>(&mut rng, None))
+        b.iter(|| generate_safe_prime_with_rng::<Uint<{ nlimbs!(256) }>>(&mut rng, 256, 256))
     });
 
     group.finish();
@@ -258,7 +258,7 @@ fn bench_gmp(c: &mut Criterion) {
     let mut group = c.benchmark_group("GMP");
 
     fn random<const L: usize>(rng: &mut impl CryptoRngCore) -> Integer {
-        let num = random_odd_uint::<L>(rng, Uint::<L>::BITS);
+        let num = random_odd_uint::<Uint<L>>(rng, Uint::<L>::BITS, Uint::<L>::BITS).get();
         Integer::from_digits(num.as_words(), Order::Lsf)
     }
 

src/hazmat/gcd.rs

@@ -1,17 +1,17 @@
-use crypto_bigint::{Limb, NonZero, Uint, Word};
+use crypto_bigint::{Integer, Limb, NonZero, Word};
 
 /// Calculates the greatest common divisor of `n` and `m`.
 /// By definition, `gcd(0, m) == m`.
 /// `n` must be non-zero.
-pub(crate) fn gcd_vartime<const L: usize>(n: &Uint<L>, m: Word) -> Word {
+pub(crate) fn gcd_vartime<T: Integer>(n: &T, m: Word) -> Word {
     // This is an internal function, and it will never be called with `m = 0`.
     // Allowing `m = 0` would require us to have the return type of `Uint<L>`
     // (since `gcd(n, 0) = n`).
     debug_assert!(m != 0);
 
     // This we can check since it doesn't affect the return type,
     // even though `n` will not be 0 either in the application.
-    if n == &Uint::<L>::ZERO {
+    if n.is_zero().into() {
         return m;
     }
 
@@ -23,7 +23,7 @@ pub(crate) fn gcd_vartime<const L: usize>(n: &Uint<L>, m: Word) -> Word {
     } else {
         // In this branch `n` is `Word::BITS` bits or shorter,
         // so we can safely take the first limb.
-        let n = n.as_words()[0];
+        let n = n.as_ref()[0].0;
         if n > m {
             (n, m)
         } else {

src/hazmat/jacobi.rs

@@ -1,6 +1,6 @@
 //! Jacobi symbol calculation.
 
-use crypto_bigint::{Limb, NonZero, Odd, Uint, Word};
+use crypto_bigint::{Integer, Limb, NonZero, Odd, Word};
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub(crate) enum JacobiSymbol {
@@ -20,37 +20,13 @@ impl core::ops::Neg for JacobiSymbol {
     }
 }
 
-// A helper trait to generalize some functions over Word and Uint.
-trait SmallMod {
-    fn mod8(&self) -> Word;
-    fn mod4(&self) -> Word;
-}
-
-impl SmallMod for Word {
-    fn mod8(&self) -> Word {
-        self & 7
-    }
-    fn mod4(&self) -> Word {
-        self & 3
-    }
-}
-
-impl<const L: usize> SmallMod for Uint<L> {
-    fn mod8(&self) -> Word {
-        self.as_limbs()[0].0 & 7
-    }
-    fn mod4(&self) -> Word {
-        self.as_limbs()[0].0 & 3
-    }
-}
-
 /// Transforms `(a/p)` -> `(r/p)` for odd `p`, where the resulting `r` is odd, and `a = r * 2^s`.
 /// Takes a Jacobi symbol value, and returns `r` and the new Jacobi symbol,
 /// negated if the transformation changes parity.
 ///
 /// Note that the returned `r` is odd.
-fn reduce_numerator<V: SmallMod>(j: JacobiSymbol, a: Word, p: &V) -> (JacobiSymbol, Word) {
-    let p_mod_8 = p.mod8();
+fn apply_reduce_numerator(j: JacobiSymbol, a: Word, p: Word) -> (JacobiSymbol, Word) {
+    let p_mod_8 = p & 7;
     let s = a.trailing_zeros();
     let j = if (s & 1) == 1 && (p_mod_8 == 3 || p_mod_8 == 5) {
         -j
@@ -60,38 +36,55 @@ fn reduce_numerator<V: SmallMod>(j: JacobiSymbol, a: Word, p: &V) -> (JacobiSymb
     (j, a >> s)
 }
 
+fn reduce_numerator_long<T: Integer>(j: JacobiSymbol, a: Word, p: &T) -> (JacobiSymbol, Word) {
+    apply_reduce_numerator(j, a, p.as_ref()[0].0)
+}
+
+fn reduce_numerator_short(j: JacobiSymbol, a: Word, p: Word) -> (JacobiSymbol, Word) {
+    apply_reduce_numerator(j, a, p)
+}
+
 /// Transforms `(a/p)` -> `(p/a)` for odd and coprime `a` and `p`.
 /// Takes a Jacobi symbol value, and returns the swapped pair and the new Jacobi symbol,
 /// negated if the transformation changes parity.
-fn swap<T: SmallMod, V: SmallMod>(j: JacobiSymbol, a: T, p: V) -> (JacobiSymbol, V, T) {
-    let j = if a.mod4() == 1 || p.mod4() == 1 {
+fn apply_swap(j: JacobiSymbol, a: Word, p: Word) -> JacobiSymbol {
+    if a & 3 == 1 || p & 3 == 1 {
         j
     } else {
         -j
-    };
+    }
+}
+
+fn swap_long<T: Integer>(j: JacobiSymbol, a: Word, p: &Odd<T>) -> (JacobiSymbol, &Odd<T>, Word) {
+    let j = apply_swap(j, a, p.as_ref().as_ref()[0].0);
+    (j, p, a)
+}
+
+fn swap_short(j: JacobiSymbol, a: Word, p: Word) -> (JacobiSymbol, Word, Word) {
+    let j = apply_swap(j, a, p);
     (j, p, a)
 }
 
 /// Returns the Jacobi symbol `(a/p)` given an odd `p`.
-pub(crate) fn jacobi_symbol_vartime<const L: usize>(
+pub(crate) fn jacobi_symbol_vartime<T: Integer>(
     abs_a: Word,
     a_is_negative: bool,
-    p_long: &Odd<Uint<L>>,
+    p_long: &Odd<T>,
 ) -> JacobiSymbol {
     let result = JacobiSymbol::One; // Keep track of all the sign flips here.
 
     // Deal with a negative `a` first:
     // (-a/n) = (-1/n) * (a/n)
     //        = (-1)^((n-1)/2) * (a/n)
     //        = (-1 if n = 3 mod 4 else 1) * (a/n)
-    let result = if a_is_negative && p_long.mod4() == 3 {
+    let result = if a_is_negative && p_long.as_ref().as_ref()[0].0 & 3 == 3 {
         -result
     } else {
         result
     };
 
     // A degenerate case.
-    if abs_a == 1 || p_long.as_ref() == &Uint::<L>::ONE {
+    if abs_a == 1 || p_long.as_ref() == &T::one() {
         return result;
     }
 
@@ -100,14 +93,14 @@ pub(crate) fn jacobi_symbol_vartime<const L: usize>(
     // Normalize input: at the end we want `a < p`, `p` odd, and both fitting into a `Word`.
     let (result, a, p): (JacobiSymbol, Word, Word) = if p_long.bits_vartime() <= Limb::BITS {
         let a = a_limb.0;
-        let p = p_long.as_limbs()[0].0;
+        let p = p_long.as_ref().as_ref()[0].0;
         (result, a % p, p)
     } else {
-        let (result, a) = reduce_numerator(result, a_limb.0, p_long.as_ref());
+        let (result, a) = reduce_numerator_long(result, a_limb.0, p_long.as_ref());
         if a == 1 {
             return result;
         }
-        let (result, a_long, p) = swap(result, a, p_long.get());
+        let (result, a_long, p) = swap_long(result, a, p_long);
         // Can unwrap here, since `p` is swapped with `a`,
         // and `a` would be odd after `reduce_numerator()`.
         let a =
@@ -127,7 +120,7 @@ pub(crate) fn jacobi_symbol_vartime<const L: usize>(
         // At this point `p` is odd (either coming from outside of the `loop`,
         // or from the previous iteration, where a previously reduced `a`
         // was swapped into its place), so we can call this.
-        (result, a) = reduce_numerator(result, a, &p);
+        (result, a) = reduce_numerator_short(result, a, p);
 
         if a == 1 {
             return result;
@@ -138,7 +131,7 @@ pub(crate) fn jacobi_symbol_vartime<const L: usize>(
         // Note that technically `swap()` only returns a valid `result` if `a` and `p` are coprime.
         // But if they are not, we will return `Zero` eventually,
         // which is not affected by any sign changes.
-        (result, a, p) = swap(result, a, p);
+        (result, a, p) = swap_short(result, a, p);
 
         a %= p;
     }