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blscurve.nim
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blscurve.nim
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# Nimbus
# Copyright (c) 2020-2024 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
# http:https://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
# http:https://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed except
# according to those terms.
import blscurve/bls_backend, stint
import blscurve/blst/[blst_lowlevel]
type
BLS_G1* = blst_p1
BLS_G2* = blst_p2
BLS_FP* = blst_fp
BLS_FP2* = blst_fp2
BLS_SCALAR* = blst_scalar
BLS_FE* = blst_fp
BLS_FE2* = blst_fp2
BLS_ACC* = blst_fp12
BLS_G1P* = blst_p1_affine
BLS_G2P* = blst_p2_affine
func fromBytes*(ret: var BLS_SCALAR, raw: openArray[byte]): bool =
const L = 32
if raw.len < L:
return false
let pa = cast[ptr array[L, byte]](raw[0].unsafeAddr)
blst_scalar_from_bendian(ret, pa[])
true
func fromBytes(ret: var BLS_FP, raw: openArray[byte]): bool =
const L = 48
if raw.len < L:
return false
let pa = cast[ptr array[L, byte]](raw[0].unsafeAddr)
blst_fp_from_bendian(ret, pa[])
true
func toBytes(fp: BLS_FP, output: var openArray[byte]): bool =
const L = 48
if output.len < L:
return false
let pa = cast[ptr array[L, byte]](output[0].unsafeAddr)
blst_bendian_from_fp(pa[], fp)
true
func pack(g: var BLS_G1, x, y: BLS_FP): bool =
let src = blst_p1_affine(x: x, y: y)
blst_p1_from_affine(g, src)
blst_p1_on_curve(g).int == 1
func unpack(g: BLS_G1, x, y: var BLS_FP): bool =
var dst: blst_p1_affine
blst_p1_to_affine(dst, g)
x = dst.x
y = dst.y
true
func pack(g: var BLS_G2, x0, x1, y0, y1: BLS_FP): bool =
let src = blst_p2_affine(x: blst_fp2(fp: [x0, x1]), y: blst_fp2(fp: [y0, y1]))
blst_p2_from_affine(g, src)
blst_p2_on_curve(g).int == 1
func unpack(g: BLS_G2, x0, x1, y0, y1: var BLS_FP): bool =
var dst: blst_p2_affine
blst_p2_to_affine(dst, g)
x0 = dst.x.fp[0]
x1 = dst.x.fp[1]
y0 = dst.y.fp[0]
y1 = dst.y.fp[1]
true
func nbits(s: BLS_SCALAR): uint =
var k = sizeof(s.l) - 1
while k >= 0 and s.l[k] == 0: dec k
if k < 0: return 0
var
bts = k shl 3
c = s.l[k]
while c != 0:
c = c shr 1
inc bts
result = bts.uint
func add*(a: var BLS_G1, b: BLS_G1) {.inline.} =
blst_p1_add_or_double(a, a, b)
func mul*(a: var BLS_G1, b: BLS_SCALAR) {.inline.} =
blst_p1_mult(a, a, b, b.nbits)
func add*(a: var BLS_G2, b: BLS_G2) {.inline.} =
blst_p2_add_or_double(a, a, b)
func mul*(a: var BLS_G2, b: BLS_SCALAR) {.inline.} =
blst_p2_mult(a, a, b, b.nbits)
func mapFPToG1*(fp: BLS_FE): BLS_G1 {.inline.} =
let z: ptr blst_fp = nil
blst_map_to_g1(result, fp, z[])
func mapFPToG2*(fp: BLS_FE2): BLS_G2 {.inline.} =
let z: ptr blst_fp2 = nil
blst_map_to_g2(result, fp, z[])
func pack(g: var BLS_G1P, x, y: BLS_FP): bool =
g = blst_p1_affine(x: x, y: y)
blst_p1_affine_on_curve(g).int == 1
func pack(g: var BLS_G2P, x0, x1, y0, y1: BLS_FP): bool =
g = blst_p2_affine(x: blst_fp2(fp: [x0, x1]), y: blst_fp2(fp: [y0, y1]))
blst_p2_affine_on_curve(g).int == 1
func subgroupCheck*(P: BLS_G1P): bool {.inline.} =
blst_p1_affine_in_g1(P).int == 1
func subgroupCheck*(P: BLS_G2P): bool {.inline.} =
blst_p2_affine_in_g2(P).int == 1
func millerLoop*(P: BLS_G1P, Q: BLS_G2P): BLS_ACC {.inline.} =
blst_miller_loop(result, Q, P)
proc mul*(a: var BLS_ACC, b: BLS_ACC) {.inline.} =
blst_fp12_mul(a, a, b)
func check*(x: BLS_ACC): bool {.inline.} =
var ret: BLS_ACC
ret.blst_final_exp(x)
ret.blst_fp12_is_one().int == 1
# decodeFieldElement expects 64 byte input with zero top 16 bytes,
# returns lower 48 bytes.
func decodeFieldElement*(res: var BLS_FP, input: openArray[byte]): bool =
if input.len != 64:
return false
# check top bytes
for i in 0..<16:
if input[i] != 0.byte:
return false
res.fromBytes input.toOpenArray(16, 63)
func decodeFE*(res: var BLS_FE, input: openArray[byte]): bool =
const
fieldModulus = StUint[512].fromHex "0x1a0111ea397fe69a4b1ba7b6434bacd764774b84f38512bf6730d2a0f6b0f6241eabfffeb153ffffb9feffffffffaaab"
if not res.decodeFieldElement(input):
return false
var z: StUint[512]
z.initFromBytesBE(input)
z < fieldModulus
func decodeFE*(res: var BLS_FE2, input: openArray[byte]): bool =
if input.len != 128:
return false
if res.fp[0].decodeFE(input.toOpenArray(0, 63)) and
res.fp[1].decodeFE(input.toOpenArray(64, 127)):
result = true
# DecodePoint given encoded (x, y) coordinates in 128 bytes returns a valid G1 Point.
func decodePoint*(g: var (BLS_G1 | BLS_G1P), data: openArray[byte]): bool =
if data.len != 128:
return false
var x, y: BLS_FP
if x.decodeFieldElement(data.toOpenArray(0, 63)) and
y.decodeFieldElement(data.toOpenArray(64, 127)):
result = g.pack(x, y)
# EncodePoint encodes a point into 128 bytes.
func encodePoint*(g: BLS_G1, output: var openArray[byte]): bool =
if output.len != 128:
return false
var x, y: BLS_FP
if g.unpack(x, y) and
x.toBytes(output.toOpenArray(16, 63)) and
y.toBytes(output.toOpenArray(64+16, 127)):
result = true
# DecodePoint given encoded (x, y) coordinates in 256 bytes returns a valid G2 Point.
func decodePoint*(g: var (BLS_G2 | BLS_G2P), data: openArray[byte]): bool =
if data.len != 256:
return false
var x0, x1, y0, y1: BLS_FP
if x0.decodeFieldElement(data.toOpenArray(0, 63)) and
x1.decodeFieldElement(data.toOpenArray(64, 127)) and
y0.decodeFieldElement(data.toOpenArray(128, 191)) and
y1.decodeFieldElement(data.toOpenArray(192, 255)):
result = g.pack(x0, x1, y0, y1)
# EncodePoint encodes a point into 256 bytes.
func encodePoint*(g: BLS_G2, output: var openArray[byte]): bool =
if output.len != 256:
return false
var x0, x1, y0, y1: BLS_FP
if g.unpack(x0, x1, y0, y1) and
x0.toBytes(output.toOpenArray(16, 63)) and
x1.toBytes(output.toOpenArray(80, 127)) and
y0.toBytes(output.toOpenArray(144, 192)) and
y1.toBytes(output.toOpenArray(208, 255)):
result = true