mirror of
https://github.com/codex-storage/nim-codex.git
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111 lines
3.4 KiB
Nim
111 lines
3.4 KiB
Nim
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## Nim-POS
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## Copyright (c) 2022 Status Research & Development GmbH
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## Licensed under either of
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## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
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## * MIT license ([LICENSE-MIT](LICENSE-MIT))
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## at your option.
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## This file may not be copied, modified, or distributed except according to
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## those terms.
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# Implementation of the BLS-based public PoS scheme from
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# Shacham H., Waters B., "Compact Proofs of Retrievability"
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# using pairing over BLS12-381 ECC
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import blscurve
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import blscurve/blst/blst_abi
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type
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ec_SecretKey* = blscurve.SecretKey
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ec_PublicKey* = blscurve.PublicKey
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ec_p1* = blst_p1
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ec_p2* = blst_p2
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ec_scalar* = blst_scalar
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ec_fr* = blst_fr
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ec_signature* = Signature
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# these need to be template as a workaround for const
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template EC_G1* : blst_p1_affine = BLS12_381_G1
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template EC_G2* : blst_p2_affine = BLS12_381_G2
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let
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ec_p1_from_affine* = blst_p1_from_affine
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ec_scalar_from_bendian* = blst_scalar_from_bendian
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ec_scalar_fr_check* = blst_scalar_fr_check
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ec_p2_from_affine* = blst_p2_from_affine
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ec_p2_mult* = blst_p2_mult
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ec_p1_mult* = blst_p1_mult
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ec_p1_add_or_double* = blst_p1_add_or_double
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ec_fr_from_scalar* = blst_fr_from_scalar
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ec_fr_mul* = blst_fr_mul
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ec_scalar_from_fr* = blst_scalar_from_fr
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ec_fr_add* = blst_fr_add
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ec_p1_on_curve* = blst_p1_on_curve
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ec_keygen* = blscurve.keyGen
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func ec_export_raw*(signature: Signature): array[96, byte] {.inline, noinit.} =
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blscurve.exportRaw(signature)
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proc ec_sign*[T: byte|char](secretKey: SecretKey, message: openarray[T]): Signature =
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blscurve.sign(secretKey, message)
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proc ec_hash_to_g1*[T,U,V: byte|char](dst: var blst_p1;
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msg: openArray[T];
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domainSepTag: openArray[U];
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aug: openArray[V]) =
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blst_hash_to_g1(dst, msg, domainSepTag, aug)
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proc pairing(a: ec_p1, b: ec_p2): blst_fp12 =
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## Calculate pairing G_1,G_2 -> G_T
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var aa: blst_p1_affine
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var bb: blst_p2_affine
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blst_p1_to_affine(aa, a)
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blst_p2_to_affine(bb, b)
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var l: blst_fp12
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blst_miller_loop(l, bb, aa)
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blst_final_exp(result, l)
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proc verifyPairingsNaive(a1: blst_p1, a2: blst_p2, b1: blst_p1, b2: blst_p2) : bool =
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let e1 = pairing(a1, a2)
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let e2 = pairing(b1, b2)
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return e1 == e2
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proc verifyPairingsNeg(a1: ec_p1, a2: ec_p2, b1: ec_p1, b2: ec_p2) : bool =
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## Faster pairing verification using 2 miller loops but ony one final exponentiation
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## based on https://github.com/benjaminion/c-kzg/blob/main/src/bls12_381.c
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var
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loop0, loop1, gt_point: blst_fp12
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aa1, bb1: blst_p1_affine
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aa2, bb2: blst_p2_affine
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var a1neg = a1
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blst_p1_cneg(a1neg, 1)
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blst_p1_to_affine(aa1, a1neg)
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blst_p1_to_affine(bb1, b1)
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blst_p2_to_affine(aa2, a2)
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blst_p2_to_affine(bb2, b2)
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blst_miller_loop(loop0, aa2, aa1)
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blst_miller_loop(loop1, bb2, bb1)
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blst_fp12_mul(gt_point, loop0, loop1)
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blst_final_exp(gt_point, gt_point)
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return blst_fp12_is_one(gt_point).bool
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proc verifyPairings*(a1: ec_p1, a2: ec_p2, b1: ec_p1, b2: ec_p2) : bool =
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## Wrapper to select verify pairings implementation
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verifyPairingsNaive(a1, a2, b1, b2)
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#verifyPairingsNeg(a1, a2, b1, b2)
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func ec_from_bytes*(
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obj: var (Signature|ProofOfPossession),
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raw: array[96, byte] or array[192, byte]
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): bool {.inline.} =
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fromBytes(obj, raw)
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func ec_verify*[T: byte|char](
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publicKey: PublicKey,
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message: openarray[T],
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signature: Signature) : bool =
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verify(publicKey, message, signature)
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