crypto/bn256: full switchover to cloudflare's code (#16301)

* crypto/bn256: full switchover to cloudflare's code

* crypto/bn256: only use cloudflare for optimized architectures

* crypto/bn256: upstream fallback for non-optimized code

* .travis, build: drop support for Go 1.8 (need type aliases)

* crypto/bn256/cloudflare: enable curve mul lattice optimization

1 files changed, 35 insertions, 0 deletions

diff --git a/crypto/bn256/bn256_slow.go b/crypto/bn256/bn256_slow.go
new file mode 100644
index 000000000..61373763b
--- /dev/null
+++ b/crypto/bn256/bn256_slow.go
@@ -0,0 +1,35 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// +build !amd64,!arm64
+
+// Package bn256 implements the Optimal Ate pairing over a 256-bit Barreto-Naehrig curve.
+package bn256
+
+import "github.com/ethereum/go-ethereum/crypto/bn256/google"
+
+// G1 is an abstract cyclic group. The zero value is suitable for use as the
+// output of an operation, but cannot be used as an input.
+type G1 = bn256.G1
+
+// G2 is an abstract cyclic group. The zero value is suitable for use as the
+// output of an operation, but cannot be used as an input.
+type G2 = bn256.G2
+
+// PairingCheck calculates the Optimal Ate pairing for a set of points.
+func PairingCheck(a []*G1, b []*G2) bool {
+	return bn256.PairingCheck(a, b)
+}