Implement bn128 precompiles (#2718)

* Implement `bn128` precompiles

* Update changelog

* Create `integration-tests/internal/builtin-precompiles`

Author: cmichi

CHANGELOG.md

@@ -6,8 +6,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 [Unreleased]
 
+### Added
+- Implement `bn128` precompiles ‒ [2708](https://github.com/use-ink/ink/pull/2718)
+
 ### Changed
-- Refactor contract ref generation and add automatic re-exporting - [#2710](https://github.com/use-ink/ink/pull/2710)
+- Refactor contract ref generation and add automatic re-exporting ‒ [#2710](https://github.com/use-ink/ink/pull/2710)
 - Implement and stabilize `terminate_contract` ‒ [2708](https://github.com/use-ink/ink/pull/2708)
 
 ## Version 6.0.0-beta
@@ -2640,4 +2643,4 @@ impl Contract {
 
 This is useful if the `impl` block itself does not contain any ink! constructors or messages, but you
 still need to access some of the "magic" provided by ink!. In the example above, you would not have
-access to `emit_event` without `#[ink(impl)]`.
+access to `emit_event` without `#[ink(impl)]`.

crates/engine/src/ext.rs

@@ -353,6 +353,27 @@ impl Engine {
 }
 
 impl Engine {
+    /// Implements the `bn128_add` G1 addition precompile.
+    pub fn bn128_add(self, _x1: U256, _y1: U256, _x2: U256, _y2: U256) -> (U256, U256) {
+        unimplemented!(
+            "`bn128_add` is not implemented in the off-chain testing environment"
+        );
+    }
+
+    /// Implements the `bn128_mul` G1 scalar-mul precompile.
+    pub fn bn128_mul(self, _x1: U256, _y1: U256, _scalar: U256) -> (U256, U256) {
+        unimplemented!(
+            "`bn128_mul` is not implemented in the off-chain testing environment"
+        );
+    }
+
+    /// Implements the `bn128_pairing` precompile.
+    pub fn bn128_pairing(self, _input: &[u8]) -> bool {
+        unimplemented!(
+            "`bn128_pairing` is not implemented in the off-chain testing environment"
+        );
+    }
+
     /// Recovers the compressed ECDSA public key for given `signature` and `message_hash`,
     /// and stores the result in `output`.
     #[allow(clippy::arithmetic_side_effects)] // todo

crates/env/src/api.rs

@@ -617,6 +617,49 @@ where
     })
 }
 
+/// Calls the `bn128_add` G1 addition precompile.
+///
+/// Inputs are affine G1 coordinates over Fq.
+/// Returns the resulting affine point or (0, 0) if the result is ∞ / invalid.
+///
+/// # Note
+///
+/// The precompile address is `0x06`. You can find its implementation here:
+/// <https://github.com/paritytech/polkadot-sdk/blob/master/substrate/frame/revive/src/precompiles/builtin/bn128.rs>
+pub fn bn128_add(x1: U256, y1: U256, x2: U256, y2: U256) -> (U256, U256) {
+    <EnvInstance as OnInstance>::on_instance(|instance| {
+        instance.bn128_add(x1, y1, x2, y2)
+    })
+}
+
+/// Calls the `bn128_mul` G1 scalar-mul precompile.
+///
+/// Multiplies an affine G1 point (x1, y1) by a scalar ∈ Fr.
+/// Returns the resulting affine point or (0, 0) if the result is ∞ / invalid.
+///
+/// # Note
+///
+/// The precompile address is `0x07`. You can find its implementation here:
+/// <https://github.com/paritytech/polkadot-sdk/blob/master/substrate/frame/revive/src/precompiles/builtin/bn128.rs>
+pub fn bn128_mul(x1: U256, y1: U256, scalar: U256) -> (U256, U256) {
+    <EnvInstance as OnInstance>::on_instance(|instance| {
+        instance.bn128_mul(x1, y1, scalar)
+    })
+}
+
+/// Calls the `bn128_pairing` precompile.
+///
+/// Input is the Solidity-ABI-encoded sequence of (G1, G2) pairs.
+/// Returns `true` iff the product of pairings evaluates to the identity.
+///
+/// # Note
+///
+/// The precompile address is `0x08`. You can find its implementation here:
+/// <https://github.com/paritytech/polkadot-sdk/blob/master/substrate/frame/revive/src/precompiles/builtin/bn128.rs>
+pub fn bn128_pairing(input: &[u8]) -> bool {
+    <EnvInstance as OnInstance>::on_instance(|instance| instance.bn128_pairing(input))
+}
+
 /// Recovers the compressed ECDSA public key for given `signature` and `message_hash`,
 /// and stores the result in `output`.
 ///

crates/env/src/backend.rs

@@ -173,6 +173,39 @@ pub trait EnvBackend {
         H: CryptoHash,
         T: scale::Encode;
 
+    /// Calls the `bn128_add` G1 addition precompile.
+    ///
+    /// Inputs are affine G1 coordinates over Fq.
+    /// Returns the resulting affine point or (0, 0) if the result is ∞ / invalid.
+    ///
+    /// # Note
+    ///
+    /// The precompile address is `0x06`. You can find its implementation here:
+    /// <https://github.com/paritytech/polkadot-sdk/blob/master/substrate/frame/revive/src/precompiles/builtin/bn128.rs>
+    fn bn128_add(&mut self, x1: U256, y1: U256, x2: U256, y2: U256) -> (U256, U256);
+
+    /// Calls the `bn128_mul` G1 scalar-mul precompile.
+    ///
+    /// Multiplies an affine G1 point (x1, y1) by a scalar ∈ Fr.
+    /// Returns the resulting affine point or (0, 0) if the result is ∞ / invalid.
+    ///
+    /// # Note
+    ///
+    /// The precompile address is `0x07`. You can find its implementation here:
+    /// <https://github.com/paritytech/polkadot-sdk/blob/master/substrate/frame/revive/src/precompiles/builtin/bn128.rs>
+    fn bn128_mul(&mut self, x1: U256, y1: U256, scalar: U256) -> (U256, U256);
+
+    /// Calls the `bn128_pairing` precompile.
+    ///
+    /// Input is the Solidity-ABI-encoded sequence of (G1, G2) pairs.
+    /// Returns `true` iff the product of pairings evaluates to the identity.
+    ///
+    /// # Note
+    ///
+    /// The precompile address is `0x08`. You can find its implementation here:
+    /// <https://github.com/paritytech/polkadot-sdk/blob/master/substrate/frame/revive/src/precompiles/builtin/bn128.rs>
+    fn bn128_pairing(&mut self, input: &[u8]) -> bool;
+
     /// Recovers the compressed ECDSA public key for given `signature` and `message_hash`,
     /// and stores the result in `output`.
     fn ecdsa_recover(

crates/env/src/engine/off_chain/impls.rs

@@ -456,6 +456,24 @@ impl EnvBackend for EnvInstance {
         <H as CryptoHash>::hash(enc_input, output)
     }
 
+    fn bn128_add(&mut self, _x1: U256, _y1: U256, _x2: U256, _y2: U256) -> (U256, U256) {
+        unimplemented!(
+            "`bn128_add` is not implemented in the off-chain testing environment"
+        );
+    }
+
+    fn bn128_mul(&mut self, _x1: U256, _y1: U256, _scalar: U256) -> (U256, U256) {
+        unimplemented!(
+            "`bn128_mul` is not implemented in the off-chain testing environment"
+        );
+    }
+
+    fn bn128_pairing(&mut self, _input: &[u8]) -> bool {
+        unimplemented!(
+            "`bn128_pairing` is not implemented in the off-chain testing environment"
+        );
+    }
+
     #[allow(clippy::arithmetic_side_effects)] // todo
     fn ecdsa_recover(
         &mut self,

crates/env/src/engine/on_chain/pallet_revive.rs

@@ -868,6 +868,80 @@ impl EnvBackend for EnvInstance {
         <H as CryptoHash>::hash(enc_input, output)
     }
 
+    fn bn128_add(&mut self, x1: U256, y1: U256, x2: U256, y2: U256) -> (U256, U256) {
+        const BN128_ADD: [u8; 20] =
+            hex_literal::hex!("0000000000000000000000000000000000000006");
+
+        let mut input = [0u8; 128];
+        input[..32].copy_from_slice(&x1.to_big_endian());
+        input[32..64].copy_from_slice(&y1.to_big_endian());
+        input[64..96].copy_from_slice(&x2.to_big_endian());
+        input[96..128].copy_from_slice(&y2.to_big_endian());
+
+        let mut output = [0u8; 64];
+        let _ = ext::call(
+            CallFlags::empty(),
+            &BN128_ADD,
+            u64::MAX,       // `ref_time` to devote for execution. `u64::MAX` = all
+            u64::MAX,       // `proof_size` to devote for execution. `u64::MAX` = all
+            &[u8::MAX; 32], // No deposit limit.
+            &U256::zero().to_little_endian(), // Value transferred to the contract.
+            &input[..],
+            Some(&mut &mut output[..]),
+        );
+        let x3 = U256::from_big_endian(&output[..32]);
+        let y3 = U256::from_big_endian(&output[32..64]);
+        (x3, y3)
+    }
+
+    fn bn128_mul(&mut self, x1: U256, y1: U256, scalar: U256) -> (U256, U256) {
+        const BN128_ADD: [u8; 20] =
+            hex_literal::hex!("0000000000000000000000000000000000000007");
+
+        let mut input = [0u8; 128];
+        input[..32].copy_from_slice(&x1.to_big_endian());
+        input[32..64].copy_from_slice(&y1.to_big_endian());
+        input[64..96].copy_from_slice(&scalar.to_big_endian());
+
+        let mut output = [0u8; 64];
+        let _ = ext::call(
+            CallFlags::empty(),
+            &BN128_ADD,
+            u64::MAX,       // `ref_time` to devote for execution. `u64::MAX` = all
+            u64::MAX,       // `proof_size` to devote for execution. `u64::MAX` = all
+            &[u8::MAX; 32], // No deposit limit.
+            &U256::zero().to_little_endian(), // Value transferred to the contract.
+            &input[..],
+            Some(&mut &mut output[..]),
+        );
+        let x2 = U256::from_big_endian(&output[..32]);
+        let y2 = U256::from_big_endian(&output[32..64]);
+        (x2, y2)
+    }
+
+    fn bn128_pairing(&mut self, input: &[u8]) -> bool {
+        const BN128_ADD: [u8; 20] =
+            hex_literal::hex!("0000000000000000000000000000000000000008");
+
+        let mut output = [0u8; 32];
+        let _ = ext::call(
+            CallFlags::empty(),
+            &BN128_ADD,
+            u64::MAX,       // `ref_time` to devote for execution. `u64::MAX` = all
+            u64::MAX,       // `proof_size` to devote for execution. `u64::MAX` = all
+            &[u8::MAX; 32], // No deposit limit.
+            &U256::zero().to_little_endian(), // Value transferred to the contract.
+            &input[..],
+            Some(&mut &mut output[..]),
+        );
+        if output[31] == 1 {
+            debug_assert_eq!(&output[..31], [0u8; 31]);
+            return true;
+        }
+        debug_assert_eq!(&output[..32], [0u8; 32]);
+        false
+    }
+
     fn ecdsa_recover(
         &mut self,
         signature: &[u8; 65],

crates/ink/src/env_access.rs

@@ -998,6 +998,42 @@ where
         output
     }
 
+    /// Calls the `bn128_add` G1 addition precompile.
+    ///
+    /// Inputs are affine G1 coordinates over Fq.
+    /// Returns the resulting affine point or (0, 0) if the result is ∞ / invalid.
+    ///
+    /// # Note
+    ///
+    /// For more details visit: [`ink_env::bn128_add`]
+    pub fn bn128_add(self, x1: U256, y1: U256, x2: U256, y2: U256) -> (U256, U256) {
+        ink_env::bn128_add(x1, y1, x2, y2)
+    }
+
+    /// Calls the `bn128_mul` G1 scalar-mul precompile.
+    ///
+    /// Multiplies an affine G1 point (x1, y1) by a scalar ∈ Fr.
+    /// Returns the resulting affine point or (0, 0) if the result is ∞ / invalid.
+    ///
+    /// # Note
+    ///
+    /// For more details visit: [`ink_env::bn128_mul`]
+    pub fn bn128_mul(self, x1: U256, y1: U256, scalar: U256) -> (U256, U256) {
+        ink_env::bn128_mul(x1, y1, scalar)
+    }
+
+    /// Calls the `bn128_pairing` precompile.
+    ///
+    /// Input is the Solidity-ABI-encoded sequence of (G1, G2) pairs.
+    /// Returns `true` iff the product of pairings evaluates to the identity.
+    ///
+    /// # Note
+    ///
+    /// For more details visit: [`ink_env::bn128_pairing`]
+    pub fn bn128_pairing(self, input: &[u8]) -> bool {
+        ink_env::bn128_pairing(input)
+    }
+
     /// Recovers the compressed ECDSA public key for given `signature` and `message_hash`,
     /// and stores the result in `output`.
     ///

integration-tests/internal/builtin-precompiles/Cargo.toml

@@ -0,0 +1,29 @@
+[package]
+name = "builtin_precompiles"
+description = "E2E tests for various builtin precompiles"
+version = "6.0.0-beta"
+authors = ["Use Ink <[email protected]>"]
+edition = "2021"
+publish = false
+
+[dependencies]
+ink = { path = "../../../crates/ink", default-features = false }
+
+[dev-dependencies]
+ink_e2e = { path = "../../../crates/e2e" }
+hex-literal = "1"
+impl-serde = { version = "0.5.0", default-features = false }
+
+[lib]
+path = "lib.rs"
+
+[features]
+default = ["std"]
+std = [
+    "ink/std",
+]
+ink-as-dependency = []
+e2e-tests = []
+
+[package.metadata.ink-lang]
+abi = "ink"