constantine/tests/support/ec_reference_scalar_mult.nim
Mamy Ratsimbazafy d376f08d1b
G2 / Operations on the twisted curve E'(Fp2) (#51)
* Split elliptic curve tests to better use parallel testing

* Add support for printing points on G2

* Implement multiplication and division by optimal sextic non-residue (BLS12-381)

* Implement modular square root in 𝔽p2

* Support EC add and EC double on G2 (for BLS12-381)

* Support G2 divisive twists with non-unit sextic-non-residue like BN254 snarks

* Add EC G2 bench

* cleanup some unused warnings

* Reorg the tests for parallelization and to avoid instantiating huge files
2020-06-15 22:58:56 +02:00

53 lines
1.9 KiB
Nim

# Constantine
# Copyright (c) 2018-2019 Status Research & Development GmbH
# Copyright (c) 2020-Present Mamy André-Ratsimbazafy
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
import
# Internals
../../constantine/config/[common, curves],
../../constantine/arithmetic,
../../constantine/elliptic/ec_weierstrass_projective
# Support files for testing Elliptic Curve arithmetic
# ------------------------------------------------------------------------------
iterator unpack(scalarByte: byte): bool =
yield bool((scalarByte and 0b10000000) shr 7)
yield bool((scalarByte and 0b01000000) shr 6)
yield bool((scalarByte and 0b00100000) shr 5)
yield bool((scalarByte and 0b00010000) shr 4)
yield bool((scalarByte and 0b00001000) shr 3)
yield bool((scalarByte and 0b00000100) shr 2)
yield bool((scalarByte and 0b00000010) shr 1)
yield bool( scalarByte and 0b00000001)
func unsafe_ECmul_double_add*(
P: var ECP_SWei_Proj,
scalar: openArray[byte],
) =
## **Unsafe** Elliptic Curve Scalar Multiplication
##
## P <- [k] P
##
## This uses the double-and-add algorithm to verify the constant-time production implementation
## This is UNSAFE to use in production and only intended for testing purposes.
##
## This is highly VULNERABLE to timing attacks and power analysis attacks
##
## `scalar` is in canonical representation in BigEndian (octet string)
var t0{.noInit.}, t1{.noInit.}: typeof(P)
t0.setInf()
t1.setInf()
for scalarByte in scalar:
for bit in unpack(scalarByte):
t1.double(t0)
if bit:
t0.sum(t1, P)
else:
t0 = t1
P = t0