crypto: Migrate ExtPoint to AffinePoint<E2>

lib/evmone_precompiles/bn254.hpp

@@ -4,6 +4,7 @@
 #pragma once
 
 #include "ecc.hpp"
+#include "pairing/field_template.hpp"
 #include <optional>
 #include <span>
 #include <vector>
@@ -52,12 +53,29 @@ struct Curve
     /// @}
 };
 
+using Fq = Curve::Fp;
+
 using AffinePoint = ecc::AffinePoint<Curve>;
 
-/// Note that real part of G2 value goes first and imaginary part is the second. i.e (a + b*i)
-/// The pairing check precompile EVM ABI presumes that imaginary part goes first.
-/// TODO: Migrate G2 input handling to AffinePoint<E2> for symmetry with G1.
-using ExtPoint = ecc::Point<std::pair<uint256, uint256>>;
+/// Fq² extension field config: base field extended by the irreducible `u² + 1`.
+/// Stays in this namespace so ADL finds multiply()/inverse() (defined in pairing/bn254/fields.hpp).
+struct Fq2Config
+{
+    using BaseFieldT = Fq;
+    using ValueT = Fq;
+    static constexpr auto DEGREE = 2;
+};
+/// Fq² element with coefficients in (real, imaginary) order.
+using Fq2 = ecc::ExtFieldElem<Fq2Config>;
+
+/// The BN254 twisted curve E₂: y² = x³ + b/ξ over Fq². G2 lives here.
+struct E2
+{
+    using Fp = Fq2;
+    static constexpr auto A = 0;
+};
+
+using ExtPoint = ecc::AffinePoint<E2>;
 
 /// Validates that point is from the bn254 curve group
 ///

lib/evmone_precompiles/pairing/bn254/fields.hpp

@@ -10,19 +10,9 @@
 namespace evmmax::bn254
 {
 using namespace intx;
-using Fq = Curve::Fp;
 
 // Extension fields implemented based on https://hackmd.io/@jpw/bn254#Field-extension-towers
-
-/// Specifies Fq^2 extension field for bn254 curve. Base field extended with irreducible `u^2 + 1`
-/// polynomial over the base field. `u` is the Fq^2 element.
-struct Fq2Config
-{
-    using BaseFieldT = Fq;
-    using ValueT = Fq;
-    static constexpr auto DEGREE = 2;
-};
-using Fq2 = ecc::ExtFieldElem<Fq2Config>;
+// Fq, Fq2Config, Fq2, and E2 live in bn254.hpp to be reachable from the precompile boundary.
 
 /// Specifies Fq^6 extension field for bn254 curve. Fq^2 field extended with irreducible
 /// `v^3 - (9 + u)` polynomial over the Fq^2 field. `v` is the Fq^6 field element.
@@ -51,13 +41,6 @@ struct Fq12Config
 };
 using Fq12 = ecc::ExtFieldElem<Fq12Config>;
 
-/// The BN254 twisted curve E₂: y² = x³ + b/ξ over Fq².
-struct E2
-{
-    using Fp = Fq2;
-    static constexpr auto A = 0;
-};
-
 /// Multiplies two Fq^2 field elements
 constexpr Fq2 multiply(const Fq2& a, const Fq2& b)
 {

lib/evmone_precompiles/pairing/bn254/pairing.cpp

@@ -136,28 +136,19 @@ std::optional<bool> pairing_check(std::span<const std::pair<AffinePoint, ExtPoin
 
     for (const auto& [p, q] : pairs)
     {
-        if (!is_field_element(q.x.first) || !is_field_element(q.x.second) ||
-            !is_field_element(q.y.first) || !is_field_element(q.y.second))
-        {
-            return std::nullopt;
-        }
-
         if (!validate(p))
             return std::nullopt;
 
-        const auto Q_aff = ecc::AffinePoint<E2>{
-            Fq2({Fq(q.x.first), Fq(q.x.second)}), Fq2({Fq(q.y.first), Fq(q.y.second)})};
-
-        const bool g2_is_inf = Q_aff == 0;
+        const bool g2_is_inf = q == 0;
 
-        // Verify that Q in on curve and in proper subgroup. This subgroup is much smaller than
-        // group containing all the points from twisted curve over Fq2 field.
-        if (!g2_is_inf && (!is_on_twisted_curve(Q_aff) || !g2_subgroup_check(Q_aff)))
+        // G2 must be on the twisted curve and in the small subgroup (Q is part of the full
+        // twisted-curve group otherwise, which would still satisfy is_on_twisted_curve alone).
+        if (!g2_is_inf && (!is_on_twisted_curve(q) || !g2_subgroup_check(q)))
             return std::nullopt;
 
-        // If any of the points is infinity it means that miller_loop returns 1. so we can skip it.
+        // If either point is infinity, miller_loop returns 1, so skip it.
         if (p != 0 && !g2_is_inf)
-            f = f * miller_loop(Q_aff, p);
+            f = f * miller_loop(q, p);
     }
 
     // final exp is calculated on accumulated value

lib/evmone_precompiles/pairing/bn254/utils.hpp

@@ -67,12 +67,6 @@ static inline const std::array<std::array<Fq2, 5>, 3> FROBENIUS_COEFFS = {
     },
 };
 
-/// Verifies that value is in the proper prime field.
-constexpr bool is_field_element(const uint256& v)
-{
-    return v < Curve::FIELD_PRIME;
-}
-
 /// Verifies that affine point over Fq^2 field is on the twisted curve.
 constexpr bool is_on_twisted_curve(const evmmax::ecc::AffinePoint<E2>& p)
 {

test/state/precompiles.cpp

@@ -550,18 +550,21 @@ ExecutionResult ecpairing_execute(const uint8_t* input, size_t input_size, uint8
     pairs.reserve(input_size / PAIR_SIZE);  // TODO: may throw std::bad_alloc.
     for (auto input_ptr = input; input_ptr != input + input_size; input_ptr += PAIR_SIZE)
     {
-        const auto p =
-            evmmax::bn254::AffinePoint::from_bytes(std::span<const uint8_t, 64>{input_ptr, 64});
+        namespace bn = evmmax::bn254;
+        auto p = bn::AffinePoint::from_bytes(std::span<const uint8_t, 64>{input_ptr, 64});
         if (!p.has_value()) [[unlikely]]
             return {EVMC_PRECOMPILE_FAILURE, 0};
 
-        const evmmax::bn254::ExtPoint q{
-            {intx::be::unsafe::load<intx::uint256>(input_ptr + 96),
-                intx::be::unsafe::load<intx::uint256>(input_ptr + 64)},
-            {intx::be::unsafe::load<intx::uint256>(input_ptr + 160),
-                intx::be::unsafe::load<intx::uint256>(input_ptr + 128)},
-        };
-        pairs.emplace_back(*p, q);
+        // G2 EVM ABI feeds the imaginary coefficient before the real one for each Fq²,
+        // so swap the offsets when reading into (real, imaginary) order.
+        const auto qx_real = bn::Fq::from_bytes(std::span<const uint8_t, 32>{input_ptr + 96, 32});
+        const auto qx_imag = bn::Fq::from_bytes(std::span<const uint8_t, 32>{input_ptr + 64, 32});
+        const auto qy_real = bn::Fq::from_bytes(std::span<const uint8_t, 32>{input_ptr + 160, 32});
+        const auto qy_imag = bn::Fq::from_bytes(std::span<const uint8_t, 32>{input_ptr + 128, 32});
+        if (!qx_real || !qx_imag || !qy_real || !qy_imag) [[unlikely]]
+            return {EVMC_PRECOMPILE_FAILURE, 0};
+        bn::ExtPoint q{bn::Fq2({*qx_real, *qx_imag}), bn::Fq2({*qy_real, *qy_imag})};
+        pairs.emplace_back(std::move(*p), std::move(q));
     }
 
     const auto res = evmmax::bn254::pairing_check(pairs);

test/unittests/evmmax_bn254_pairing_test.cpp

@@ -24,39 +24,26 @@ TEST(evmmax, bn254_pairing)
     };
 
     const auto Q1 = ExtPoint{
-        {
-            0x04bf11ca01483bfa8b34b43561848d28905960114c8ac04049af4b6315a41678_u256,
-            0x209dd15ebff5d46c4bd888e51a93cf99a7329636c63514396b4a452003a35bf7_u256,
-        },
-        {
-            0x120a2a4cf30c1bf9845f20c6fe39e07ea2cce61f0c9bb048165fe5e4de877550_u256,
-            0x2bb8324af6cfc93537a2ad1a445cfd0ca2a71acd7ac41fadbf933c2a51be344d_u256,
-        },
+        Fq2({Fq(0x04bf11ca01483bfa8b34b43561848d28905960114c8ac04049af4b6315a41678_u256),
+            Fq(0x209dd15ebff5d46c4bd888e51a93cf99a7329636c63514396b4a452003a35bf7_u256)}),
+        Fq2({Fq(0x120a2a4cf30c1bf9845f20c6fe39e07ea2cce61f0c9bb048165fe5e4de877550_u256),
+            Fq(0x2bb8324af6cfc93537a2ad1a445cfd0ca2a71acd7ac41fadbf933c2a51be344d_u256)}),
     };
     // -Q1:
-    const auto nQ1 =
-        ExtPoint{Q1.x, {Curve::FIELD_PRIME - Q1.y.first, Curve::FIELD_PRIME - Q1.y.second}};
+    const auto nQ1 = -Q1;
     // -Q1 * 16:
     const auto nQ1_16 = ExtPoint{
-        {
-            0x14191bd65f51663a1d4ad71d8480c3c3260d598aab6ed95681f773abade7fd7a_u256,
-            0x299c79589dfb51fd6925fce3a7fc15c441fdafaa24f0d09b7c443befdddde4e5_u256,
-        },
-        {
-            0x1d710ac19a995c6395f33be7f3dcd75e0632a006d196da6b4c9ba78708b6bb78_u256,
-            0xcae1001513ae5ddf742aa6dc2f52457d9b14e17765dd74fc098ad06045d434e_u256,
-        },
+        Fq2({Fq(0x14191bd65f51663a1d4ad71d8480c3c3260d598aab6ed95681f773abade7fd7a_u256),
+            Fq(0x299c79589dfb51fd6925fce3a7fc15c441fdafaa24f0d09b7c443befdddde4e5_u256)}),
+        Fq2({Fq(0x1d710ac19a995c6395f33be7f3dcd75e0632a006d196da6b4c9ba78708b6bb78_u256),
+            Fq(0xcae1001513ae5ddf742aa6dc2f52457d9b14e17765dd74fc098ad06045d434e_u256)}),
     };
     // -Q1 * 17:
     const auto nQ1_17 = ExtPoint{
-        {
-            0x11eeb08db4fe0df9d7617f11f5f8f488d643510f825f3730ffb038c84c9260fd_u256,
-            0x12bf46039aa40a61762bf97b1bb028cebc6d42e46bbbe67f715eda54808b74c4_u256,
-        },
-        {
-            0x42b65e62de1fd24534db81fd72e7ee832637948c1c466ccb08171e503f23e72_u256,
-            0x197a5efb333448885788690df5af2211c1697dd8b7b1f8845b4e30a909d2b0f5_u256,
-        },
+        Fq2({Fq(0x11eeb08db4fe0df9d7617f11f5f8f488d643510f825f3730ffb038c84c9260fd_u256),
+            Fq(0x12bf46039aa40a61762bf97b1bb028cebc6d42e46bbbe67f715eda54808b74c4_u256)}),
+        Fq2({Fq(0x42b65e62de1fd24534db81fd72e7ee832637948c1c466ccb08171e503f23e72_u256),
+            Fq(0x197a5efb333448885788690df5af2211c1697dd8b7b1f8845b4e30a909d2b0f5_u256)}),
     };
 
     {
@@ -108,27 +95,16 @@ TEST(evmmax, bn254_pairing_invalid_input)
             0x22980b2e458ec77e258b19ca3a7b46181f63c6536307acae03eea236f6919eeb_u256,
             0x4eab993e2ba2cca2b08c216645e3fbcf80ae67515b2c49806c17b90c9d3cad3_u256,
         },
-        {
-            {
-                0x04bf11ca01483bfa8b34b43561848d28905960114c8ac04049af4b6315a41678_u256,
-                0x209dd15ebff5d46c4bd888e51a93cf99a7329636c63514396b4a452003a35bf7_u256,
-            },
-            {
-                0x120a2a4cf30c1bf9845f20c6fe39e07ea2cce61f0c9bb048165fe5e4de877550_u256,
-                0x2bb8324af6cfc93537a2ad1a445cfd0ca2a71acd7ac41fadbf933c2a51be344d_u256,
-            },
+        ExtPoint{
+            Fq2({Fq(0x04bf11ca01483bfa8b34b43561848d28905960114c8ac04049af4b6315a41678_u256),
+                Fq(0x209dd15ebff5d46c4bd888e51a93cf99a7329636c63514396b4a452003a35bf7_u256)}),
+            Fq2({Fq(0x120a2a4cf30c1bf9845f20c6fe39e07ea2cce61f0c9bb048165fe5e4de877550_u256),
+                Fq(0x2bb8324af6cfc93537a2ad1a445cfd0ca2a71acd7ac41fadbf933c2a51be344d_u256)}),
         },
     }};
 
     EXPECT_EQ(pairing_check(valid_input), false);
 
-    {
-        // Coordinate not a field element
-        auto input = valid_input;
-        input[0].second.x.second = Curve::FIELD_PRIME;
-        EXPECT_EQ(pairing_check(input), std::nullopt);
-    }
-
     {
         // Point P (G1) not on curve
         auto input = valid_input;
@@ -139,21 +115,17 @@ TEST(evmmax, bn254_pairing_invalid_input)
     {
         // Point Q (G2) not on curve
         auto input = valid_input;
-        input[0].second.x.first += 1;
+        input[0].second.x.coeffs[0] += Fq{1};
         EXPECT_EQ(pairing_check(input), std::nullopt);
     }
 
     {
-        // Q not in proper group. Q id a member of small subgroup on twisted curve over Fq^2
+        // Q not in proper group. Q is a member of small subgroup on twisted curve over Fq^2.
         const ExtPoint Q{
-            {
-                0x13d841ba7ff3c6efd6870c3fea13a3ecab0423af5e4db9c5d28a6b46a05cd57b_u256,
-                0x1a2b1eaa7b20faae36d26eff4db6e336c34434b66eded3cc5303d51ae353f478_u256,
-            },
-            {
-                0x2d3e8808aa7a7fffa8f871f10df8d59c6dd725889c46e9136e01cb2465b20723_u256,
-                0x1d5224817b8714531fc77e20b975178b1b3044f4b729fa3230db03dc0088ebdb_u256,
-            },
+            Fq2({Fq(0x13d841ba7ff3c6efd6870c3fea13a3ecab0423af5e4db9c5d28a6b46a05cd57b_u256),
+                Fq(0x1a2b1eaa7b20faae36d26eff4db6e336c34434b66eded3cc5303d51ae353f478_u256)}),
+            Fq2({Fq(0x2d3e8808aa7a7fffa8f871f10df8d59c6dd725889c46e9136e01cb2465b20723_u256),
+                Fq(0x1d5224817b8714531fc77e20b975178b1b3044f4b729fa3230db03dc0088ebdb_u256)}),
         };
 
         auto input = valid_input;
@@ -171,14 +143,10 @@ TEST(evmmax_bn254, evm_codes_example)
         0x2c0f001f52110ccfe69108924926e45f0b0c868df0e7bde1fe16d3242dc715f6_u256,
     };
     const auto q1 = ExtPoint{
-        {
-            0x22606845ff186793914e03e21df544c34ffe2f2f3504de8a79d9159eca2d98d9_u256,
-            0x1fb19bb476f6b9e44e2a32234da8212f61cd63919354bc06aef31e3cfaff3ebc_u256,
-        },
-        {
-            0x2fe02e47887507adf0ff1743cbac6ba291e66f59be6bd763950bb16041a0a85e_u256,
-            0x2bd368e28381e8eccb5fa81fc26cf3f048eea9abfdd85d7ed3ab3698d63e4f90_u256,
-        },
+        Fq2({Fq(0x22606845ff186793914e03e21df544c34ffe2f2f3504de8a79d9159eca2d98d9_u256),
+            Fq(0x1fb19bb476f6b9e44e2a32234da8212f61cd63919354bc06aef31e3cfaff3ebc_u256)}),
+        Fq2({Fq(0x2fe02e47887507adf0ff1743cbac6ba291e66f59be6bd763950bb16041a0a85e_u256),
+            Fq(0x2bd368e28381e8eccb5fa81fc26cf3f048eea9abfdd85d7ed3ab3698d63e4f90_u256)}),
     };
 
     // Pair 2
@@ -187,14 +155,10 @@ TEST(evmmax_bn254, evm_codes_example)
         0x30644e72e131a029b85045b68181585d97816a916871ca8d3c208c16d87cfd45_u256,
     };
     const auto q2 = ExtPoint{
-        {
-            0x091058a3141822985733cbdddfed0fd8d6c104e9e9eff40bf5abfef9ab163bc7_u256,
-            0x1971ff0471b09fa93caaf13cbf443c1aede09cc4328f5a62aad45f40ec133eb4_u256,
-        },
-        {
-            0x23a8eb0b0996252cb548a4487da97b02422ebc0e834613f954de6c7e0afdc1fc_u256,
-            0x2a23af9a5ce2ba2796c1f4e453a370eb0af8c212d9dc9acd8fc02c2e907baea2_u256,
-        },
+        Fq2({Fq(0x091058a3141822985733cbdddfed0fd8d6c104e9e9eff40bf5abfef9ab163bc7_u256),
+            Fq(0x1971ff0471b09fa93caaf13cbf443c1aede09cc4328f5a62aad45f40ec133eb4_u256)}),
+        Fq2({Fq(0x23a8eb0b0996252cb548a4487da97b02422ebc0e834613f954de6c7e0afdc1fc_u256),
+            Fq(0x2a23af9a5ce2ba2796c1f4e453a370eb0af8c212d9dc9acd8fc02c2e907baea2_u256)}),
     };
 
     const std::vector<std::pair<AffinePoint, ExtPoint>> pairs = {{p1, q1}, {p2, q2}};
@@ -212,14 +176,10 @@ TEST(evmmax_bn254, evm_codes_example_changed_order)
         0x2c0f001f52110ccfe69108924926e45f0b0c868df0e7bde1fe16d3242dc715f6_u256,
     };
     const auto q1 = ExtPoint{
-        {
-            0x1fb19bb476f6b9e44e2a32234da8212f61cd63919354bc06aef31e3cfaff3ebc_u256,
-            0x22606845ff186793914e03e21df544c34ffe2f2f3504de8a79d9159eca2d98d9_u256,
-        },
-        {
-            0x2bd368e28381e8eccb5fa81fc26cf3f048eea9abfdd85d7ed3ab3698d63e4f90_u256,
-            0x2fe02e47887507adf0ff1743cbac6ba291e66f59be6bd763950bb16041a0a85e_u256,
-        },
+        Fq2({Fq(0x1fb19bb476f6b9e44e2a32234da8212f61cd63919354bc06aef31e3cfaff3ebc_u256),
+            Fq(0x22606845ff186793914e03e21df544c34ffe2f2f3504de8a79d9159eca2d98d9_u256)}),
+        Fq2({Fq(0x2bd368e28381e8eccb5fa81fc26cf3f048eea9abfdd85d7ed3ab3698d63e4f90_u256),
+            Fq(0x2fe02e47887507adf0ff1743cbac6ba291e66f59be6bd763950bb16041a0a85e_u256)}),
     };
 
     // Pair 2
@@ -228,14 +188,10 @@ TEST(evmmax_bn254, evm_codes_example_changed_order)
         0x30644e72e131a029b85045b68181585d97816a916871ca8d3c208c16d87cfd45_u256,
     };
     const auto q2 = ExtPoint{
-        {
-            0x1971ff0471b09fa93caaf13cbf443c1aede09cc4328f5a62aad45f40ec133eb4_u256,
-            0x091058a3141822985733cbdddfed0fd8d6c104e9e9eff40bf5abfef9ab163bc7_u256,
-        },
-        {
-            0x2a23af9a5ce2ba2796c1f4e453a370eb0af8c212d9dc9acd8fc02c2e907baea2_u256,
-            0x23a8eb0b0996252cb548a4487da97b02422ebc0e834613f954de6c7e0afdc1fc_u256,
-        },
+        Fq2({Fq(0x1971ff0471b09fa93caaf13cbf443c1aede09cc4328f5a62aad45f40ec133eb4_u256),
+            Fq(0x091058a3141822985733cbdddfed0fd8d6c104e9e9eff40bf5abfef9ab163bc7_u256)}),
+        Fq2({Fq(0x2a23af9a5ce2ba2796c1f4e453a370eb0af8c212d9dc9acd8fc02c2e907baea2_u256),
+            Fq(0x23a8eb0b0996252cb548a4487da97b02422ebc0e834613f954de6c7e0afdc1fc_u256)}),
     };
 
     const std::vector<std::pair<AffinePoint, ExtPoint>> pairs = {{p1, q1}, {p2, q2}};