| ... | ... | @@ -4,6 +4,8 @@ const testing = std.testing; |
| 4 | 4 | |
| 5 | 5 | const Secp256k1 = @import("../secp256k1.zig").Secp256k1; |
| 6 | 6 | |
| 7 | const lambda: u256 = 0x5363ad4cc05c30e0a5261c028812645a122e22ea20816678df02967c1b23bd72; |
| 8 | |
| 7 | 9 | test "secp256k1 ECDH key exchange" { |
| 8 | 10 | const io = testing.io; |
| 9 | 11 | const dha = Secp256k1.scalar.random(io, .little); |
| ... | ... | @@ -138,6 +140,43 @@ test "secp256k1 double base multiplication" { |
| 138 | 140 | try testing.expect(pr1.equivalent(pr2)); |
| 139 | 141 | } |
| 140 | 142 | |
| 143 | test "secp256k1 public multiplication" { |
| 144 | const io = testing.io; |
| 145 | const n = Secp256k1.scalar.field_order; |
| 146 | const p = Secp256k1.random(io); |
| 147 | for ([_]u256{ 1, 2, n - 1, lambda, n - lambda, (1 << 128) - 1 }) |x| { |
| 148 | var s: [32]u8 = undefined; |
| 149 | std.mem.writeInt(u256, &s, x, .big); |
| 150 | for ([_]Secp256k1{ p, Secp256k1.basePoint }) |q| { |
| 151 | try testing.expect((try q.mulPublic(s, .big)).equivalent(try q.mul(s, .big))); |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | var s_n: [32]u8 = undefined; |
| 156 | std.mem.writeInt(u256, &s_n, n, .little); |
| 157 | try testing.expectError(error.NonCanonical, p.mulPublic(s_n, .little)); |
| 158 | } |
| 159 | |
| 160 | test "secp256k1 scalar split" { |
| 161 | const io = testing.io; |
| 162 | const Scalar = Secp256k1.scalar.Scalar; |
| 163 | const n = Secp256k1.scalar.field_order; |
| 164 | var lambda_s: [32]u8 = undefined; |
| 165 | std.mem.writeInt(u256, &lambda_s, lambda, .little); |
| 166 | const lambda_scalar = try Scalar.fromBytes(lambda_s, .little); |
| 167 | inline for (.{ .little, .big }) |endian| { |
| 168 | const k = Secp256k1.scalar.random(io, endian); |
| 169 | const split = try Secp256k1.Endormorphism.splitScalar(k, endian); |
| 170 | const r1 = try Scalar.fromBytes(split.r1, endian); |
| 171 | const r2 = try Scalar.fromBytes(split.r2, endian); |
| 172 | try testing.expect(r1.add(r2.mul(lambda_scalar)).equivalent(try Scalar.fromBytes(k, endian))); |
| 173 | for ([_][32]u8{ split.r1, split.r2 }) |r_s| { |
| 174 | const r = std.mem.readInt(u256, &r_s, endian); |
| 175 | try testing.expect(@min(r, n - r) < 1 << 128); |
| 176 | } |
| 177 | } |
| 178 | } |
| 179 | |
| 141 | 180 | test "secp256k1 scalar inverse" { |
| 142 | 181 | const expected = "08d0684a0fe8ea978b68a29e4b4ffdbd19eeb59db25301cf23ecbe568e1f9822"; |
| 143 | 182 | var out: [32]u8 = undefined; |
Frank Denis <124872+jedisct1@users.noreply.github.com> 2026-09-27 17:38:01+02:00