Bitwise math

aiken.toml

@@ -1,6 +1,6 @@
 name = "aiken-lang/stdlib"
 version = "main"
-compiler = "v1.1.11"
+compiler = "v1.1.12"
 plutus = "v3"
 description = "The Aiken Standard Library"
 

lib/aiken/crypto/bitwise.ak

@@ -0,0 +1,134 @@
+use aiken/builtin
+
+pub opaque type State<t> {
+  inner: Int,
+}
+
+pub const zero = State { inner: 0 }
+
+pub const one = State { inner: 1 }
+
+pub fn add_bits(field: Int, big_endian: Bool) {
+  fn(state: State<t>, bytes: ByteArray) -> State<t> {
+    builtin.bytearray_to_integer(big_endian, bytes)
+      |> builtin.add_integer(state.inner)
+      |> builtin.mod_integer(field)
+      |> State
+  }
+}
+
+pub fn add_int(field: Int) {
+  fn(state: State<t>, int: Int) -> State<t> {
+    state.inner + int
+      |> builtin.mod_integer(field)
+      |> State
+  }
+}
+
+pub fn add_state(field: Int) {
+  fn(state: State<t>, other: State<t>) -> State<t> {
+    state.inner + other.inner
+      |> builtin.mod_integer(field)
+      |> State
+  }
+}
+
+pub fn sub_bits(field: Int, big_endian: Bool) {
+  fn(state: State<t>, bytes: ByteArray) -> State<t> {
+    builtin.bytearray_to_integer(big_endian, bytes)
+      |> builtin.subtract_integer(state.inner)
+      |> builtin.mod_integer(field)
+      |> State
+  }
+}
+
+pub fn sub_int(field: Int) {
+  fn(state: State<t>, int: Int) -> State<t> {
+    state.inner - int
+      |> builtin.mod_integer(field)
+      |> State
+  }
+}
+
+pub fn sub_state(field: Int) {
+  fn(state: State<t>, other: State<t>) -> State<t> {
+    state.inner - other.inner
+      |> builtin.mod_integer(field)
+      |> State
+  }
+}
+
+pub fn mul_bits(field: Int, big_endian: Bool) {
+  fn(state: State<t>, bytes: ByteArray) -> State<t> {
+    builtin.bytearray_to_integer(big_endian, bytes)
+      |> builtin.multiply_integer(state.inner)
+      |> builtin.mod_integer(field)
+      |> State
+  }
+}
+
+pub fn mul_int(field: Int) {
+  fn(state: State<t>, int: Int) -> State<t> {
+    state.inner * int
+      |> builtin.mod_integer(field)
+      |> State
+  }
+}
+
+pub fn mul_state(field: Int) {
+  fn(state: State<t>, other: State<t>) -> State<t> {
+    state.inner * other.inner
+      |> builtin.mod_integer(field)
+      |> State
+  }
+}
+
+pub fn scale(
+  self: State<t>,
+  e: Int,
+  mul: fn(State<t>, State<t>) -> State<t>,
+) -> State<t> {
+  if e < 0 {
+    zero
+  } else if e == 0 {
+    one
+  } else if e % 2 == 0 {
+    scale(mul(self, self), e / 2, mul)
+  } else {
+    mul(self, scale(mul(self, self), ( e - 1 ) / 2, mul))
+  }
+}
+
+/// A faster version of `scale` for the case where the exponent is a power of two.
+/// That is, the exponent `e = 2^k` for some non-negative integer `k`. Which is used alot in zk-SNARKs.
+pub fn scale2(self: State<t>, k: Int, mul: fn(State<t>, State<t>) -> State<t>) {
+  if k < 0 {
+    zero
+  } else {
+    do_scale2(self, k, mul)
+  }
+}
+
+fn do_scale2(self: State<t>, k: Int, mul) -> State<t> {
+  if k == 0 {
+    self
+  } else {
+    do_scale2(mul(self, self), k - 1, mul)
+  }
+}
+
+pub fn neg(field: Int) {
+  fn(state: State<t>) -> State<t> {
+    ( field - state.inner ) % field
+      |> State
+  }
+}
+
+pub fn to_int(state: State<t>) -> Int {
+  state.inner
+}
+
+pub fn from_int(int: Int, field: Int) -> State<t> {
+  int % field
+    |> State
+}

lib/aiken/crypto/bls12_381/g1.ak

@@ -11,6 +11,7 @@
 //// This module ensures that all operations respect the properties of the BLS12-381 curve and the mathematical structure of the G1 group.
 
 use aiken/builtin
+use aiken/crypto/bitwise.{State}
 use aiken/crypto/bls12_381/scalar.{Scalar}
 
 /// The compressed generator of the G1 group of the BLS12-381 curve.
@@ -95,12 +96,12 @@ test sub_1() {
 
 /// Exponentiates a point in the G1 group with a `scalar`.
 /// This operation is equivalent to the repeated addition of the point with itself `e` times.
-pub fn scale(point, e: Scalar) {
+pub fn scale(point, e: State<Scalar>) {
   builtin.bls12_381_g1_scalar_mul(scalar.to_int(e), point)
 }
 
 test scale_1() {
-  expect Some(x) = scalar.new(2)
+  let x = scalar.from_int(2)
   builtin.bls12_381_g1_add(generator, generator) == scale(generator, x)
 }
 

lib/aiken/crypto/bls12_381/g2.ak

@@ -11,6 +11,7 @@
 //// This module ensures that all operations respect the properties of the BLS12-381 curve and the mathematical structure of the G2 group.
 
 use aiken/builtin
+use aiken/crypto/bitwise.{State}
 use aiken/crypto/bls12_381/scalar.{Scalar}
 
 /// The compressed generator of the G2 group of the BLS12-381 curve.
@@ -104,12 +105,12 @@ test sub_1() {
 
 /// Exponentiates a point in the G2 group with a `scalar`.
 /// This operation is equivalent to the repeated addition of the point with itself `e` times.
-pub fn scale(point, e: Scalar) {
+pub fn scale(point, e: State<Scalar>) {
   builtin.bls12_381_g2_scalar_mul(scalar.to_int(e), point)
 }
 
 test scale_1() {
-  expect Some(x) = scalar.new(2)
+  let x = scalar.from_int(2)
   builtin.bls12_381_g2_add(generator, generator) == scale(generator, x)
 }